The basic Hydroponic System types

How hydroponic systems work may seem complicated at first, but once you understand them, you'll see how they work is actually really quite simple. There are six types of hydroponic systems (Drip System, Ebb & Flow, N.F.T., Water Culture, Aeroponics, and Wick). The plants roots need 3 things, water/moisture, nutrients, and oxygen. What makes the six types of hydroponic systems different is simply how they deliver these three things to the plants roots. Each type of system is described in the detail in the links (by name) to the left and below.

Regardless of what they may choose to call them, all hydroponic systems are based on these six types, and are either one of these types of systems, or a combination of two or more of the six types. There are thousands of ways to make variations, as well as alter any aspect of any of the six types of systems. So once your familiar with how each of the three roots needs (water, nutrients, and oxygen) are delivered in each type of hydroponic system, you'll quickly be able to identify what type of system any hydroponic system is.

See Our List of Free Build Your Own Hydroponic system Design Plans

The Six Types of Hydroponic Systems

1. Drip System

2. Ebb- Flow (Flood & Drain)

3. N.F.T. (Nutrient Film Technique)

4. Water Culture

5. Aeroponics

6. Wick System

What about Aquaponics? Some may argue that aquaponics is another type of hydroponic system. But aquaponics isn't really a 7th type of hydroponic system, simply because what makes aquaponics different is how the nutrients are formulated. Not how the nutrients (or even water and oxygen) are delivered to the roots. The technique of aquaponics and supplying the nutrients from decomposing fish waste can be used in any of the 6 types of hydroponic systems. Simply by replacing the regular nutrient reservoir with a fish tank reservoir.

There's a lot more to aquaponics than that because your trying to control specific nutrient levels naturally with microorganisms, bacteria, and micro flora living in the fish water to decompose the fish waste into the nutrients the plants can use. Simply put, aquaponics is a process of making nutrients out of fish waste, basically your making your own nutrients. But that doesn't affect how water, nutrients, or oxygen are delivered to the plants roots.

Before Designing and Building a Hydroponic System

Before building a hydroponic system, it's important to first consider the type of plants you want to grow in it, as well as the space you have to grow them in. Then you'll want to make sure to design the system to be able to accommodate the plants needs (plant size, root size, oxygen to the roots, water consumption, etc. etc.) even after they reach full size. While one type of hydroponic system may be well suited for growing some types of plants, it may not be the best choice for growing others.

Some basic things that you want to keep in mind when designing and building (even buying) any hydroponic system are; First, you will probably want to use it more than once, so you should think about things like how hard it will be to break it down and take it apart to clean it thoroughly between plantings. Also, should you have a problem while the plants are still growing, you should think about how hard will it be to fix the problems without doing damage to the plants or system.

You can grow most any type of plants in any type of hydroponic system if you design the system to accommodate the plants needs, even when they reach full size. However it still might be easier, take less maintenance, as well as be cheaper to grow them in another type of hydroponic system instead. Also, when growing many types of plants, it's often much better to grow them in different systems designed for those specific crops, rather than trying to grow them all in one large system.

Hydroponic System Only Need a Few Basic Parts to Build

Growing Chamber (or tray), The growing chamber is the part of the hydroponic system where the plants roots will be growing. Simply put, the growing chamber is the container for the root zone. This area provides plant support, as

well as is where the roots access the nutrient solution. It also protects the roots from light, heat, and pests. It's important to keep the root zone cool and light proof. Prolonged light will damage the roots, and high temps in the root zone will cause heat stress to your plants, as well as fruit and flower drop as a result of heat stress.

The size and shape of the growing chamber really just depends on the type of hydroponic system your building, as well as the type of plants you'll be growing in it. Bigger plants have bigger root systems, and need more space to hold them in. The designs here are endless. Almost anything can be used as the growing chamber, you just don't want to use anything made of metal or it could corrode or react with the nutrients. If you look around you'll get lots of ideas of what and how you can easily use many different things for building the growing chamber of your hydroponic system.

Reservoir, The reservoir is the part of the hydroponic system that holds the nutrient solution. The nutrient solution consists of plant nutrients that are mixed in water. Depending on the type of hydroponic system, the nutrient solution can be pumped from the reservoir up to the growing chamber (root zone) in cycles using a timer, as well as continually without a timer, or the roots can even hang down into the reservoir 24/7, making the reservoir the growing chamber also.

You can make a reservoir out of just about anything plastic that holds water. As long as it doesn't leak, holds enough water, and is cleaned out well first it can be used as reservoir. Read this article for more about how big your nutrient reservoir should be. A reservoir also needs to be light proof. If you can hold it over your head and see light coming through it, it's not light proof. But it's easy to make any container light proof by painting it, covering it, or wrapping something like bubble wrap insulation around it. Algae and microorganisms can begin growing with even low light levels.

Submersible Pump,Most hydroponic systems use a submersible pump to pump the water (nutrient solution) from the reservoir up to the growing chamber/root zone for the plants. Submersible pumps can easily be found at hydropnic supply shop, or most home improvement stores with garden supplies as fountain and/or pond pumps. They will also come in a wide variety of sizes. Read this page for how to decide what size pump you need for your hydroponic system?

The submersible pumps are basically nothing more than an impeller that uses a electromagnet to spin it. They can also easily be taken all apart to be cleaned thoroughly. If it doesn't come with a filter, you can easily make one by cutting a piece of furnace filter screen or similar material to fit. You should clean both the pump and filter regularly to keep them clean.

Delivery system, A hydroponic systems water/nutrient solution delivery system is really quite simple, as well as extremely customizable when building your own hydro systems. Besides the pump, it's really nothing more than just the pluming the water/nutrient solution goes through to get to the plants roots in the growing

chamber, and back to the reservoir again. Typically the simplest and best materials to use for the nutrient delivery system are a combination of standard PVC tubing and connectors, standard garden irrigation tubing and connectors, as well as blue or black vinyl tubing.

Depending on the type of hydroponic system you build, you may want to use drip emitters or sprayers as part of your nutrient solution delivery system. While they can be useful, they also can clog. So if you do, make sure you have extras you can quickly swap out while you clean the clogged ones. We try to avoid using emitters because they do clog, as well as cost extra money.

Simple Timer,Depending on the type of hydroponic system you build, and where you place the system to grow your plants. You may need one or two simple timers. If you use artificial lighting to grow the plants instead of natural sunlight, you'll want a timer to control the on/off times for the lighting system. For flood and drain, drip, and aeroponic systems you'll need a timer to control the on/off times for the submersible water pump. Some types of aeroponic systems may need a special timer. Visit the aeroponic systems page to find out more about the types of aeroponic systems, and timers for them.

Standard everyday light timers work fine for both the lights as well as the submersible pumps. However we do recommend making sure the timer is rated for 15 amps rather than 10 amps. Fifteen amp timers are often called heavy duty, if not just check the back of the package or timer for the 15 amp rating. Also try and get one for outdoor use, they usually have a cover and are usually water resistant.

We don't recommend the more expensive digital timers over the analogue dial type. Simply because digital timers will loose all memory, as well as your settings if they loose power or get unplugged, even for one second for any reason (unless you find one with a battery backup). They often don't have any more actual on/off settings than the analogue type as well. Just make sure the timer you get has pins all the way around the dial.

Air Pump,Other than in water culture systems, air pumps are optional in hydroponic systems. But using them has benefits, and air pumps are relatively inexpensive. Air pumps can be found anywhere they sell aquarium supplies. Air pumps simply just supply air and oxygen to the water and roots. Air is pumped through an air line to air stones that create a bunch of small bubbles that rise up through the nutrient solution.

In water culture systems the air pump helps keep the plants roots from suffocating while their submerged in the nutrient solution 24/7. For any other type of hydroponic system, the air pump is typically used in the reservoir. It helps to increase dissolved oxygen levels in the water up and keep the water oxygenated. Visit this page for more aboutdissolved oxygen levels.

Other advantage's of using air pumps are that as the air bubbles rise, they keep the water and nutrients moving and circulating, this keeps the nutrients evenly mixed all the time. The circulating oxygenated water also helps reduce pathogens from gaining a foothold in the reservoir.

Grow Lights,Grow lights are an optional part of hydroponic systems. Depending on where you plan to put your hydroponic system, and grow your plants. You could choose to either use natural sunlight, or artificial light to grow your plants with. If you can make use of it we prefer natural sunlight, it's is free and doesn't require any extra equipment. However if there just isn't enough natural sunlight where you put your hydroponic system, or at that time of year, you'll need to use at least some artificial light to grow your plants.

Grow lights are different than most standard household lights. Grow lights are designed to emit certain color spectrums that mimic natural sunlight. The plants use these color spectrums (wavelengths) of light to conduct photosynthesis. The plants need to conduct photosynthesis in order to grow and produce fruit and flowers. So the type, as well as the amount of light a plant gets will greatly affect the plants ability to photosynthesize, and thus grow. Visit our page on lighting and grow lights for hydroponic plants for more about the different types of artificial lights used to grow plants.

Hydroponic Drip Systems

Drip systems are one of the most widely used types of hydroponic systems around the world, both for home growers as well as commercial growers alike. That's mainly because it's an easy concept and needs few parts, but yet it's a very versatile and effective type of hydroponic system. Even though it's an easy concept, it won't limit your imagination when building your own systems. The way a drip system works is just like it sounds, you simply drip nutrient solution on the plants roots to keep them moist.

Hydroponic drip systems can easily be designed in many ways, as well as from small to large systems. But their especially useful for larger plants that take a lot of root space. That's because you don't need large volumes of water to flood the system, and the drip lines are easy to run over longer spaces. As well as when using a larger amount of growing media for larger plants, more growing media retains more moisture than smaller amounts, and that's particularly beneficial to large plants because it's more forgiving to the plants. Forgiving meaning that the plants arent as sencitive to watering times, so they don't stress imeditaly if they don't get waterd on time for one reason or another.

What you'll need to build a drip system is:

A container for the plant's roots to grow in.

A container (reservoir) to hold the nutrient solution.

A submersible fountain/pond pump.

A light timer to turn the pump on and off.

Some tubing to run from the pump in the reservoir to the plants (and/or the drip lines if you use different sizes).

Tubing (PVC or flexible tubing) to run the return lines for the extra nutrient solution from the plants back to the to the reservoir.

(optional) You can use drip emitters, or you can just poke small holes in the tubing with a hot paper clip for the nutrient solution to drip out of like we like to do.

Growing media for the plants roots to grow in and help support the plants weight.

How a hydroponic drip system operates is simple. Water (nutrient solution) is pumped up from the reservoir through tubing to the top of the growing media (where the plants roots are), from there it drips out of the tubing onto the growing media. The nutrient solution drains down soaking both the roots and growing media all the way to the bottom of the container. From there the nutrient solution flows through an opening/s, and gravity allows the nutrient solution to flow downhill through tubing all the way back to the reservoir. It's important to remember that the plants growing container needs to be at least 6-8 inches or so above the top of the reservoir, so that gravity can drain the excess water back do the to it (water wont flow uphill without a pump).

There are really two types of hydroponic drip systems

Recirculating/recovery drip systems For home growers the recirculating drip systems are by far the most commonly used. The recirculating drip systems is like it sounds, it simply refers to reusing/cycling the used nutrient solution after it has wet the roots back to the reservoir where it can be recirculated through the system, and used over and over again. Recirculating systems are also called recovery systems because it refers to recovering the used nutrient solution so it can be recirculated through the system again.

Like any hydroponic system that recirculates, a recirculating drip system's nutrient solution can change in both the pH as well as nutrient strength levels as the plants use up the nutrients in the water when it circulates over and over. Because of this, recirculating systems require that you periodically check and adjust the pH as needed, as well as change the nutrient solution regularly to maintain a balanced nutrient solution for the plants.

Non-recirculating/non-recovery drip systems For commercial growers the non-recirculating/non-recovery drip systems are most common. While it sounds like a waist of water and nutrients not to recover and reuse it, commercial growers actually waist very little. They do this by precisely timing their watering cycles. Using special "cycle timers" they can adjust the watering times down to the minute, or even second if they need to. They water just long enough to wet the growing media. So the water (nutrient solution) they drip onto the plants is absorbed and held in the growing medium where the plants roots access it, and very little if any runs off. From time to time they flush the growing medium with plain fresh water to avoid nutrient build up in the growing medium over time.

The nutrient solution in non-recirculating/non-recovery drip systems tend to be less maintenance, mainly because of the fact that none of the used nutrient solution is recycled back into the reservoir. This means that you can fill the reservoir with a balanced, pH adjusted nutrient solution and it won't change, so you don't need to keep monitoring it. As long as you keep the water in the reservoir slowly moving/circulating so that the heavier mineral elements don't settle at the bottom, it will remain a balanced pH adjusted nutrient solution.

Ebb & Flow - (Flood and Drain) System

Flood and Drain (Ebb and Flow) systems are very popular with home hydroponic growers for many reasons. Besides how easy they are for anyone to build, you can use almost any materials you have laying around to build them with, so you don't need to spend much money to grow plants hydroponically. Also they can be built to fit in any available space you might have (both indoors or outdoors), and there is no limit to the different and imaginative ways to design them for that space. Along with being inexpensive and easy to build, plants grow very well in flood and drain systems. The flood and drain system works basically like it sounds, by simply flooding the plants root system with nutrient solution. Only periodically rather than continuously.

How a hydroponic flood and drain system operates quite simple. The main part of the flood and drain system holds the containers the plants are growing in. It can be just one plant, or many plants/containers in series. A timer turns on the pump, and water (nutrient solution) is pumped through tubing from the reservoir up into the main part of the system using a submersible fountain/pond pump. The nutrient solution continues to fill (flood) the system until it reaches the height of the preset overflow tube so that it soaks the plants roots. The overflow tube should be set to about 2 inches below the top of the growing media.

When the water filling/flooding the system reaches the overflow tube height, it drains back down to the reservoir where it recirculates back through the system again. The overflow tube sets the water level height in the flood and drain system, as well as makes sure the water (nutrient solution) doesn't spill out

the top of the system while the pump is on. When the pump shuts off, the water siphons back down into the reservoir through the pump (draining the system).

What you need to build a Flood and Drain (Ebb and Flow) system:

A container for the plant's roots to grow in.

A container (reservoir) to hold the nutrient solution.

A submersible fountain/pond pump.

A light timer to turn the pump on and off.

Some tubing to run from the pump in the reservoir to the system to be flooded.

An overflow tube set to the height you want the water level.

Growing medium of some kind.

There are many different ways to build a flood and drain system, and they are very good for growing small to medium size plants. Even for growing large plants with larger flood and drain system designs. You can use just about anything to build one including buckets, tubes, 2 liter bottles, storage totes, water bottles, an old ice chest, trash cans etc.. Just about anything that can hold water can be used. The imagination doesn't stop there either, there are many ways to flood and drain the roots in the system too. Below are some examples of how the three most common ways used to flood and drain the systems work.

(Tip 1) Make sure there is a way air can get in the top of the overflow without spilling water out. A "T" connector with an extension that is a few inches above the water line will work nicely. This will keep air pockets from forming in the system and make sure it floods and drains properly.

(Tip 2) Make sure the overflow tube is bigger than the water inlet tube from the pump. Otherwise because the water is only going out through gravity, and water is coming in through pressure from the pump, you could wind up pumping in more water than what is going out the overflow. That would lead to water building up and spilling out the top of your system, unless you reduce the pressure (volume) from the pump.

There are basically three main types of flood and drain system setups

Plant containers in series designThis type of setup is most commonly used when many different containers with plants are being watered (flooded) at the same time. It's important to remember that the system

with the plants (containers) to be flooded (watered) needs to be above the reservoir, like on a table top or bench. That way the water can flow back to the reservoir by simple gravity, and thus drain the system correctly.

First multiple containers are all connectedtogether through tubing so that when the system is flooded, they all flood evenly, and all at the same time. For simplicity, instead of having a separate overflow for each container being flooded, there's usually only one overflow tube. It connects to the system at the base where all the containers are connected to. And when the water height reaches the top of the overflow, it spills

over and goes back to the reservoir to be pumped through the system again. The height of this one overflow tube will set the height of the water level in all of the connected containers with the plants in them (as long as it's level). You can change the water height in all of the connected containers by simply adjusting the height of the single overflow tube.

Flooding tray designThe flooding table/tray flood and drain (ebb and flow) system type setup is useful when you want to place plants in the system temporarily, need to be moving them around a lot,

or starting plants to be placed in another larger system. Instead of flooding separate containers with plants in it, this method only floods one container. Usually a shallow square or rectangle container that sets on top of a table. The reservoir usually sits directly underneath with easy access.

Water is pumped up from the reservoir into the flooding tray on one side, and the overflow is on the other side of the flooding tray. That makes sure the water actually circulates from one side of the tray/table to the other. Like any flood and drain (ebb and flow) system, the overflow tube height sets the water height during the flooding cycle, and can be adjusted as needed.

The plants are grown in regular plastic pots or baskets, and placed in the flooding tray like regular potted plants. However, unlike regular potted plants, hydroponic growing media is used to pot the plants instead of using potting soil. Once the plants get big enough, they can be transferred into a permanent hydroponic system.

One downside to using the flooding table is the algae growth, and should be cleaned out regularly. Because the top of the tray is usually left open, light is allowed to get in to the nutrient solution in the bottom of the tray, That allows algae to grow. The algae alone isn't really bad for the plants, but it does use up dissolved oxygen in the water.

Serge tank flood and drain (ebb and flow) system design

The serge tank type of flood and drain setup is useful when more vertical space is needed. Typically with flood and drain systems, the reservoir is always lower than the

hydropnic system. That's so the water (nutrient solution) can drain out of the system through gravity back into the reservoir through the overflow, and when the pump is off. But you can still set up a flood and drain system even when the water level in the reservoir is higher than the hydroponic system it's supposed to flood and drain back from. That is with the use of a serge tank.

The serge tank type of flood and drain system costs more to build because there are many more parts

needed. It works on the principal that water seeks it's own level. In other words, the water height in one container will be the same in another container when they are connected below the water line. The serge tank serves as a temporary reservoir that controls the water height in all the containers with the plants in them, and is only full during the flooding cycle.

The serge tank flood and drain (ebb and flow) system operates by pumping water (nutrient solution) from the much larger main reservoir into the serge tank when the pump timer goes on. As the water level rises in the serge tank, the water level rises evenly in all the connected plant containers at the same time. When the water level gets high enough, a float

valve in the serge tank turns on a pump in the serge tank. The pump in the serge tank then pumps water back into the main reservoir. At this time both the pumps are on (pump in main reservoir, and serge tank).

After the timer for the pump in the main reservoir shuts off, the pump in the serge tank is still on. The pump in the serge tank continues pumping all the water back into the main reservoir (draining the system) until the water level gets low enough. At that point a second float valve shuts off the pump in the serge tank.

N.F.T. (Nutrient Film Technique) System

The N.F.T. system (Nutrient Film Technique) is quite popular with home hydroponic growers as well. Mainly because of it's fairly simple design. However N.F.T. systems are best suited for, and most commonly used for growing smaller quick growing plants like different types of lettuce. Along with growing lettuce, some commercial growers also grow different types of herbs and baby greens using N.F.T. systems.

While there are a lot of different ways design an N.F.T. system, they all have the same characteristic of a

very shallow nutrient solution cascading downward through the tubing. Where the bare roots of the plants come in contact with the water, and can absorb the nutrients from it. The major downside to an N.F.T. systems is that the plants are very sensitive to interruptions in the flow of water from power outages (or whatever reason). The plants will begin to wilt very quickly any time the water stops flowing through the system.

What you need to build a N.F.T. system:

Container to hold the nutrient solution (a reservoir)

Submersible fountain/pond pump

Tubing to distribute water from the pump to the N.F.T. growing tubes

Growing tubes for the plants to grow in (also called a gully/channel)

starter cubes, or small baskets and growing media to start seedlings in

Return system (tubing, channels) to guide the used nutrient solution back to the reservoir

How a hydroponic N.F.T. system operates is fairly simple. Nutrient solution is pumped up from the reservoir, usually to a manifold that connects the larger tubing to a number of smaller ones. Each one of these smaller tubes runs nutrient solution to one side of each one of the growing channels/gully's with the plants in it. A thin layer (film) of the nutrient solution flows through each of the channel's with the plants in it to the other side, passing by each plant and wetting the roots on the bottom of the channel as it does. The nutrient solution flows from one side to the other because the channel is sloped slightly so the water flows down hill.

The plants in the growing tubes (channel/gully) are typically suspended above the water by placing seedlings started in starter cubes or small one inch baskets of growing media into small holes in the top of the tube. The roots of the seedlings hang down to the bottom of the tube/channel where they get nutrients from the shallow film of nutrient solution flowing by. The excess nutrient solution flowing out of the low end of each of the channels drains into another channel or tube, and guided back to the reservoir where it is recirculated through the system again.

While the nutrient solution flowing through the channels is very shallow, the entire plants root mass remains moist from the roots being able to wick up moisture on the outside of the roots, as well as through humidity that's kept within the tube/channel. The roots that are suspended between the base of the plant and the water level in the channel not only have moisture to access, but are also able to get plenty oxygen from the air surrounding them within the tube/channel as well.

Commercial growers typically use specially made channels/gully's for N.F.T. systems that have flat bottoms with grooves running lengthwise along the channel. These grooves allow water to flow underneath the root mass and help keep it from pooling or damming up. Home growers often use vinyl rain gutter down spouts for their channels. These vinyl down spouts have similar grooves, but cost just a fraction of what the commercially made channels/gully's cost. Home growers also often use round ADS (Advanced Drainage System) irrigation tubing for N.F.T. systems. The ADS tubing doesn't have grooves, but with increasing the slope to compensate, the round tubing works well also.

N.F.T. system Flow rate, and channel slopeHow deep should the water be, and how fast should the water be flowing are the two most common questions asked about this type of system. First the slope of the channel controls how fast the water goes through the tube/channel (not the water pump or).

The recommended slope for a N.F.T. system is typically a 1:30 to 1:40 ratio. That is for every 30 to 40 inches of horizontal length, one inch of drop (slope) is recommended. We recommend when designing your N.F.T. systems, you design it so you can adjust the slope while the plants are still growing. That's because as the root systems get bigger, they may cause it to pool and dam up the water flow. If it's adjustable you can tilt it more to compensate if needed. Also when building your N.F.T. systems, try and keep the channels/gully's as true as possible. If they sag in spots, water will pool up in those areas.

The recommended flow rate for a N.F.T. system is typically between 1/4 gallon to 1/2 gallon per minute (1 to 2 liter's) for each grow tube (channel/gully). Or between 15 gallons to 30 gallons per hour (60 to 120 liter's). While the plants are just seedlings the recommended flow rate can be cut in half, and then increased as the plants get bigger. Flow rates much higher or lower than these have sometimes been associated with nutrient deficiencies. Also nutrient deficiencies have sometimes been seen when growing tubes (channel/gully) are longer than 30 to 40 feet (10 to 15 meters). However it's been shown that having a second nutrient feed line half way down the growing tube (channel/gully) eliminates that issue.

Water Culture System

Water Culture systems are about the simplest of all six types of hydroponic systems. While technically simple, they are still very effective for growing plants hydroponiclly. Not only do

a lot of home hydroponic growers really like using water culture systems, but many commercial growers use this type of system on a large scale as well. Mainly because the water culture systems is a simple and easy concept. It's also a very inexpensive type of system to build, and another reason why it's popular with home growers as well. Even though the concept is simple, there are plenty of imaginative ways to use and build water culture systems out of different materials.

What you need to build a Water Culture system:

Container to hold the nutrient solution (reservoir)

Aquarium air pump

Air line/hose

Air stones (or soaker hose) to create the small bubbles

Baskets, pots, or cups to hold the plants

Some type of growing media

How a hydroponic Water Culture system operates is easy. The plant is actually suspended in baskets right above the nutrient solution in the reservoir. Usually by styrofoam

floating on top, or through holes cut in the lid covering the reservoir. The roots hang down from baskets the plants are in, and hang down directly into the nutrient solution where they are submerged. The roots remain submerged all the time 24/7. The roots don't suffocate because they get the air and oxygen they need from air bubbles rising through the nutrient solution, as

well as from dissolved oxygen in the water itself.

The more air bubbles the better for water culture systems. The bubbles rising should make the water look like water boiling at a heavy rolling boil. The bubbles should be rising up through, and making direct contact with the roots as they rise to the top of the water to be most effective for the plants. There are actually two ways of providing aeration and dissolved oxygen to the nutrient solution.

Types of aeration

Air bubblesAn aquarium air pump and air stones are typically used to provide air bubbles to the nutrient solution for water culture systems, as well as other types of hydroponic systems. The air pump provides the air volume, and is connected to air stones with an air line/tubing. The air stones are made of a porous rock like material, the small pores create small individual air bubbles that rise to the top of the water (nutrient solution).

Soaker hose can be used in place of air stones to create the air bubbles as well. The soaker hose creates even smaller air bubbles. The smaller the air bubbles, the better for aerating the nutrient solutions. Smaller air bubbles provide more contact surface with the water. The contact between the air bubbles and water helps to replace the dissolved oxygen taken up by the plants roots.

Falling waterThough not typical in water culture systems for home growers, surface agitation from falling water splashing around is another very good way of aerating the nutrient solution. The higher the water is falling from, and/or the more volume of water falling, the more downward force it has when it hits the waters surface. The more downward force, the deeper the agitation and more aeration (dissolved oxygen) provided. This method of aeration is more common in commercial water culture systems because they use large volumes of water compared to home growers.

Recirculating Water Culture systemsAnother variation of the typical water culture system is a recirculating water culture system. The recirculating system works like a flood and drain system but never drains. You can have as many growing containers (water culture reservoirs) as you want connected to one central reservoir. Each growing container has its own fill line, as well as a drain/overflow tube that drains back to the central reservoir.

Some growers will use buckets instead of wide shallow containers. Each bucket with their own plant in it, and of coarse filled with nutrient solution. They may have a row of these buckets. Using a fountain/pond pump to pump the nutrient solution up to each of the buckets. As the water fills the buckets, the excess water spills over into the overflow tube and flows back to the reservoir where it's recirculated back through the system again.

Most growers that recirculate the nutrient solution like this for their water culture systems only use an

air pump in the central reservoir, rather than in each individual bucket (mainly to save money). They let the water pump run 24/7 all the time. However if you have air bubbles running in each bucket like a typical water culture system, you can vary the on time for the water pump. Also the plants would benefit from the direct contact with the rising air bubbles contacting the roots.

Recirculating the water allows you to be able to utilize falling water as a source of aeration in the system. Also you don't need to keep checking the water level in each container to replace the water the plants drank up (you just check and replace it in the central reservoir), a nice benefit when you are growing large, or many plants in the same system. Just about all the large commercially operated water culture systems recirculate water through the system.

DWC (Deep Water Culture)

The term "DWC" is often used incorrectly when describing water culture systems. So what is "DWC," and why isn't "DWC" one of the six types of hydroponic systems? Well, that's because it's simply not a different type of hydroponic system at all. As you can see by the full name "Deep Water Culture," it's just a variation of the already existing type of hydroponic system called a water culture system. The word "Deep" in front is only used to describe some water culture systems when the water depth in the system is deeper than 8-10 inches, then it can be defined as an actual DWC system. However regardless of the water depth, DWC systems are still water culture systems.

Most of the time the water/nutrient solution depth doesn't need to be deeper than 8 inches. That's really only needed for larger plants that have larger root systems that need more space, and/or drink up a lot more water. Or when using a container like a bucket that needs to be filled high enough to reach the plants main root ball near the top sufficiently. Plants like the size of most varieties of lettuce can easily be grown using only 4-6 inches of water in water culture systems.

Now with that said, their's no difference between how a typical water culture system and a DWC (deep water culture) system works or functions. Their exactly the same, the only difference between the two is the depth of the water in the system. Regardless of whether it's a typical water culture system, an actual DWC system, or even a recirculating standard water culture or true DWC system, you still want to make sure you have enough water volume, and good oxygenation to the root system to support the plants. Even when they reach full size.

Water volume is different than water height. If you take a gallon of water and pour it in a wide bucket, the water height may only be a inch or two high, but you pour the same gallon of water in a 3 inch wide tube, the water height will be closer to 2 feet high. So water volume and height are two completely different things. There's more about how much water volume you should be using per plant in this article "What size reservoir do I need"

Should the water level be above or below the baskets?

There's often confusion and sometimes maybe even debate on where the water/nutrient solution level should be in water culture systems. Should the basket be touching the water, or hanging just above it? There are pros and cons for both, but there is no right or wrong, it can be either. The water level is also very quick and easy to change in a water culture system by simply adding more water, or taking some out.

When the air bubbles reach the top of the water, they pop on the waters surface. When they pop they splash tiny little water droplets an inch or two above the water's surface. How much of these tiny water droplets get splashed around depends largely on how much air is actually being supplied, and thus how many air bubbles are rising to the surface from the air stones.

When the basket is not touching the water and hanging just above it, these tiny splashing water droplets help keep the growing media near the bottom of the baskets damp. How damp depends on how many air bubbles there are popping and splashing on the water's surface near the basket. A good comparison is comparing it to boiling water (heavy rolling boil, a rolling boil, boiling, just simmering). With a heavy rolling boil being best, and just simmering being minimal. Another factor is the type of growing media that's being used. Some growing media will absorb and hold moisture quicker and easier than others, and that will make a big difference as well.

When the basket's are touching the water, the growing media in the baskets can absorb/wick up more water than if they were hanging above it, and this can sometimes be beneficial. But here again the type of growing media is going to make a big difference because some growing media will absorb and hold moisture quicker and easier than others. Thus can become completely water logged near the bottom of the baskets if it's in constant contact with the water. If it does, just lower the water level so the baskets are hanging above the water instead, or use a different type of growing media.

It's also important to mention that how big the plant is makes a difference as well. The plants roots will fallow the water/nutrient solution. Meaning they will go, and grow anywhere that has moisture. If the plant is small and the roots haven't grown out the bottom of the basket yet, it may be beneficial to have the baskets touching the water. At least until the roots are growing out the bottom and long enough to remain submerged.

Even when the bottom of the baskets are nice and moist from plenty of tiny water droplets splashing around by the popping air bubbles while hanging above the water. The extra moisture close to the plants main root ball from the growing media directly wicking up water/nutrient solution while the baskets are touching the water, can speed up root growth while the plants and root mass are still small.

The Kratky Method

To begin with I first need to say the called Kratky method is not a new or different type of hydroponic

system. I say "so called" because it's really just variation of a standard water culture system, but has sometimes been commonly referred to by a person's name (renaming it) instead. As far as I can tell, the variation was dubbed the Kratky Method after B.A. Kratky at the University of Hawaii who teaches non-recirculating hydroponic methods.

Non recirculating hydroponic systems (also referred to as "run to waste" systems) don't circulate water/nutrient solution from the reservoir to the plants and back again to the reservoir. They still pump water from the reservoir to the plants, but then allow the water/nutrient solution to drain off onto the ground, or into a drain system to discard any runoff. It sounds wasteful, but non recirculating systems can be very efficient and have very little runoff if done right. Water culture systems by definition are non-recirculating, but can be modified to be circulating systems as well.

The hydroponic system sometimes referred to as the Kratky method is simply a water culture system without the air pump, as well as part NFT system. It's a water culture system because the plants hang above the water/nutrient reservoir the roots hang down into. It's also part NFT system because like NFT systems, there is a gap between the basket holding the plant and water the roots sit in. This gap is an air pocket and is supposed to replace the air pump in a standard water culture system.

While the plants are small the basket is supposed to touch the water so the roots can begin growing out the bottom. As the plants grow and the roots get longer, the plant drinks up some of the water as well. That lowers the water level leaving a air gap. Without the air pump to replace the dissolved oxygen and oxygenate the water, the plant's need the air gap to be able to get the oxygen from. This type of system design is useful in places where electricity is non existent or unreliable.

However this methods does have it's distinct drawbacks. The air pump does more than just supply dissolved oxygen in water culture systems. The rising bubbles also keep the water moving around. When the water/nutrient solution is stagnant, the mineral salts (nutrients) settle near the bottom. As a result the nutrient balance becomes uneven (very strong near the bottom, and very weak near the top). The rising air bubbles from the air pump create movement in the water that keeps the nutrient solution mixing all the time, and thus nutrients evenly distributed throughout the water as well.

Also, while the plants roots are able to get oxygen when using the Kratky method, the roots above the water line cant get nutrients, and the roots below the water line cant get oxygen because they have already depleted the dissolved oxygen in the water early on, and there is nothing to replace it. That's a source of stress for the plant. Think of it like being in swimming pool and not being able to move while having your nose above water so you could breath, and having your mouth below the water line and able to drink water so you don't dehydrate. You can survive this way if you had to, but it would be very uncomfortable.

Plants are adaptable and will always try to adapt to their environment and surroundings as best they can. But the conditions provided when using the Kratky method are far from ideal conditions. While they are far from ideal conditions, and the cost to run an air pump 24/7 and/or otherwise replace the

dissolved oxygen is extremely low. In areas where the electricity is very unreliable or nonexistent, the Kratky method can be a beneficial and useful option.

Aeroponic System

While the concept of the aeroponic system is quite simple, it's actually the most technical of all 6 types of hydroponic systems. However it's still fairly easy to build your own basic aeroponic system, and a lot of home growers like growing in them as well, and even get really good results using this type of hydroponic system.

Like with any other type of hydroponic system, you can use many different kinds of materials to build it, as well as many different types of design setups to fit in your space. Your really only limited by the space you have, and your imagination.

Some advantages to using an aeroponic systems are they typically use little to no growing media. The roots get maximum oxygen, and the plants grow more rapidly as a result. Aeroponic systems also generally use less water than any other type of hydroponic system (especially true aeroponic systems). Also harvesting is usually easier, especially for root crops.

However there are a few downsides to aeroponic systems as well. Besides being a bit more expensive to build. The mister/sprinkler heads can clog from build up of the dissolved mineral elements in the nutrient solution. So make sure to have extras on hand to swap out when they do clog while you clean them. Also because the plants roots are hanging in mid air by design in aeroponic systems, the plants roots are much more vulnerable to drying out if there is any interruption in the watering cycle. Therefor, even any temporary power outage (for any reason) could cause your plants to die much more quickly than any other type of hydroponic system. Also there's a reduced margin for error with the nutrient levels in aeroponic systems, especially the true high pressure systems.

What you'll need to build your own basic Aeroponic system:

Container to hold the nutrient solution (a reservoir).

Submersible fountain/pond pump.

Tubing to distribute water from the reservoir pump to the mister heads in the growing chamber.

Enclosed growing chamber for the root zone.

Mister/sprinkler heads.

Water tight container for the growing chamber where the plants root systems will be.

Tubing to return the excess nutrient solution back to the reservoir.

Timer (preferably a cycle timer) to turn on and off the pump.

How the aeroponic system operates is a fairly easy concept. First the purpose of the roots hang in mid air is so they can get the maximum amount of oxygen that they can get. The high volume of oxygen the roots get allows the plans to grow faster than they would otherwise, and the main benefit to this type of hydroponic system.

Second, there is typically very little if any growing media is used, exposing all the plants roots. The plants are suspended either by small baskets, or closed cell foam plugs that compress around the plants stem. These baskets or foam plugs fit in small holes at the top of the growing chamber. The roots hang down inside the growing chamber where they get sprayed with nutrient solution from mister heads at regular short cycles. The regular watering cycles keep the roots moist and from drying out, as well as provides the nutrients the plants need to grow. The growing chamber the roots are in should be light proof, and almost air tight. It does need to allow fresh air in so the roots can get plenty of oxygen, but you don't want water to spill out, or pests to get in. Also you want the root chamber to hold in humidity. Ultimately what you want is the roots to get plenty of moisture, fresh oxygen, and nutrients. A a well designed aeroponics system provides a good balance of all three of those elements to the roots at the same time.

Lastly, a major factor in aeroponic systems is the water droplet size. Roots sprayed with a fine mist will grow much faster, bushier, and with more surface area to absorb nutrients and oxygen with than roots sprayed with small streams of water like from small sprinkler heads. That translates into the plant canopy growing more rapidly as well. Aeroponic system types are categorized by the water droplet size.

There are three types of Aeroponic Systems

Low pressure Aeroponic Systems (soakaponics)Also termed "soakaponics" low pressure aeroponic systems are what most people are familiar with when they think of aeroponics. That's mainly because most all aeroponic systems sold at stores selling hydroponics supply's are low pressure systems. While the low pressure systems work very nicely, the large water droplet size is much different than in the high pressure systems.

The main reason the low pressure aeroponic systems are so popular is that they don't require much more in the way of cost or special equipment than other types of hydroponic systems. The simplicity and

low cost of low pressure systems makes this type of aeroponic system very attractive to many home growers.

While you don't need any special equipment or a special water pump. The standard fountain/pond pumps will do just fine. You do however want a pump that's stronger than you would for any other type of hydroponic system. That's the main and most important difference. That's because the pressure in the system will drop some with each sprinkler head you add. Fountain and pond pumps don't give a psi (pressure) rating, but the more GPH (gallons per hour) it can put out closer to the "max head height" the stronger (more pressure) the pump has.

You will want enough sprinkler heads that the spray overlaps, and completely covers the entire root zone. Even as the plants get bigger and the root mass gets bigger. As the root mass gets big, it's often hard for the spray from the sprinkler heads to penetrate the thick root mass. If you design your low pressure aeroponic system so the roots are sprayed from above the root mass or near the top of it, the water will trickle down through the root mass much better than trying to spray them from below.

High pressure Aeroponic Systems (true aeroponic systems)While the low pressure systems are the most common, high pressure aeroponic systems are the "true aeroponic" systems. That's because it takes the higher pressure (60-90 psi) to properly atomize the water into a fine mist with a very small water droplet size. This fine mist allows the roots to get a lot more oxygen than in low pressure systems. However it's more complicated and expensive to build a high pressure aeroponic system.

What you'll need to build your own true high pressure Aeroponic system:

Accumulator tank (to act as the pressurized reservoir tank).

Solenoid valve (to open and close the feed line to the mister heads).

Cycle timer (to open and close the solenoid valve).

Fine spray mister heads (to spray the roots with a fine mist).

Small air compressor (to pressurize the accumulator tank).

Enclosed growing chamber for the root zone.

A collection reservoir to collect the runoff if you plan to recirculate the nutrient solution.

While the basic design of the growing chamber and plant support can remain the same as with low pressure systems. The water (nutrient solution) delivery system is much different. Because of how often a pump would need to turn on and off (100's to 1,000's of times a day) it would ware out very quickly. So the water pump is eliminated in high pressure aeroponic systems.

To do that they pressurize the reservoir. The easiest way to do that is by using an accumulator tank

similar to the type used in RO (reverse osmosis) water systems. It's basically nothing more than a tank with a rubber divider/diaphragm in the center, creating two sides. Water (nutrient solutions) goes in one side, and compressed air goes in the other. The air is filled until the pressure reaches about 60 to 90 psi. That pressure pushes against the rubber diaphragm and pressurizes the reservoir side with the nutrient solution in it to the same psi.

A water line runs from the reservoir to the mister heads in the enclosed growing chamber to mist the roots. A Solenoid valve is used to open and close the water flow through the line to the mister heads. The Solenoid valve open and close timing is controlled by a cycle timer. The cycle timer can open and close the Solenoid for as little as one second, to as long as the grower wants. Typically it's open/on for just a few seconds at a time, and off for only minutes before it sprays again. The cycle timer opens and closes the solenoid watering the plants roots with mist on this type of "on/off cycle" all day long.

Ultrasonic foggersUltrasonic foggers have also been used to create a mist in aeroponic systems, however with mixed results. Ultrasonic foggers are most commonly used to create visual displays in ponds, as well as on stage. They are also often sold around halloween with the halloween decorations too. While they do create a mist with a very small water droplet size, there is very little actual moisture in the mist/fog.

The mist created from ultrasonic foggers also tends to drop to the bottom of the container. Making it hard to make sure the roots are completely covered by the mist all the time. Another issue with using foggers is that the plates tend to clog with mineral build up. The only plates that have shown to work with any reliability are the more expensive Teflon heads. They can sometimes be cleaned using white vinegar, or water and pH down, and wiping them off with a Q-tip. Some growers have combined using ultrasonic foggers along with the low pressure aeroponic design in the same system. .

Wick System

The wick system is the simplest of all six types of hydroponic systems. That's because traditionally it doesn't have any moving parts, thus it doesn't use any pumps or

electricity. However some people still like using an optional air pump in the reservoir. Because it doesn't need electricity to work, it's also quite useful in places where electricity cant be uses, or is unreliable.

The wick system is an easy type of system to build when first learning about hydroponics, and/or you just your want to get your feet wet first. This type of hydroponic system is also often used by teachers in classrooms as experiments for kids. Both to help explain how plants grow, as well as getting them interested in hydroponics.

What you need to build a wick system:

A bucket or container for the plant.

A bucket or container for the reservoir.

A good wicking growing media like coco coir, Vermiculite, or perlite.

Some strips of material like felt or good wicking rope.

How a wick system operates is like it sounds, it basically just wicks up nutrient solution from the reservoir to the plants using the process of capillary action. Meaning it sucks

up water to the plants through the wick like a sponge. Typically good wick systems will have at least two or more good size wicks to supply enough water (nutrient solution) to the plant. The bucket/container with the plant in it basically sits right above the container used for the reservoir. That way the water doesn't need to travel up very far to get to the growing media with plants.

Downside of wick systemsThe biggest downside's to a hydroponic wick systems is that they don't really work well for larger plants that need to drink up more water. Their really more suited to grow smaller non-fruiting plants, like lettuce and herbs. While the wick does suck up (wick up) moisture to the plants roots, the larger the plant is, the more water it will need to drink up. If they are fruiting plants, they will need even more water to support the growth of all the water absorbing fruit as well.

Wick systems also have the disadvantage of being less efficient at delivering nutrients. Heavier feeding plants may need nutrients faster than the wicks can supply them to the roots. Lettuce and herbs are generally light feeders, while plants like tomato's, peppers and most fruiting plants are heavier feeders. Another downside to wick systems is that plants don't absorb nutrients and water evenly, and the wick cant tell what nutrients the plant needs. The plants take the nutrients and water it needs, and leaves the rest of the nutrients in the growing medium. This can eventually cause a toxic buildup of mineral salts in

the growing media. So flushing the excess nutrients from the root zone (growing media) with plain fresh water should be done regularly, like once a week or so.

WicksThe wick itself is probably the most important part of the wick system, because without a good absorbent wick the plants would not get the moisture and nutrients it needs. You will likely need to do some testing of different materials to see what works best for you. When looking for a good wicking material, you'll want to use something that's absorbent, but is still resistant to rotting. Then washing the wick good first before you use it, can significantly improve the wicking ability of most materials.

Some common materials people have used for wick systems are things like, fibrous rope, propylene felt strips, tiki torch wicks, rayon rope or mop head strands, braided polyurethane yarn, wool felt, wool rope or strips, nylon rope, cotton rope, stripe of fabric from old clothing or blankets etc. etc.

Make sure to use enough wicks to support the plants water usage. That will depend greatly on how you build your wick system, type of plant your growing, and growing medium you use. You'll likely need at least 2-4 wicks unless it's a real small system. Also the shorter up the wick the water has to go from the reservoir to the growing media and roots, the more water it can transport to the growing media.

Once the nutrient solution makes it up the wick to the growing media, you want to use a very absorbent growing media to further wick up and hold moisture. Some of the most commonly used growing media's for wick systems are things like coco coir, Vermiculite or perlite. And in some cases, even water absorbing polymer crystals have been used too. The Reservoir The wick system reservoir can be large or small, you just don't want it to ever run dry. Also you want the water level to remain high enough so the water (nutrient solution) doesn't need to travel up very far to get to the growing media and root zone. You'll want to top off the reservoir with fresh nutrient solution as needed, as well as clean it out and change it completely once in a while too. Simply because algae and/or microorganisms can begin growing in the food rich water, especially if it's not light proof.

Because the wick sucks up water and nutrients evenly, and the plants don't use or absorb them evenly, a build up of excess nutrient salts can build up in the growing media over time. So you'll want to flush it with plain fresh water regularly as well. Probably something like about every couple weeks. That will reduce the likelihood of the nutrient salts building up and reaching toxic levels for the plants.

Optional air pumpUsing an air pump and air stone to aerate the water in a wick system isn't necessary, however it can be beneficial. While the roots should be able to get oxygen from the small air pockets in the growing medium, they also absorb dissolved oxygen directly from the water itself as well. Along with helping to aerate the water, the moving, and rising bubbles keep the water circulating. Keeping the nutrient solution water moving around keeps the nutrients in it evenly mixed up all the time. If the water is still,

the nutrients can settle toward the bottom over time. However if you are going to use an air pump anyway, you may want to just build a water culture system instead.

Nutrients for Hydroponic systems

Hydroponic nutrients can be a complex issue or as simple as mixing and pouring. Anyone not familiar with hydroponic nutrients should just stick with a proven formula from a reputable manufacture, and simply fallow the directions on the container. This will let you learn the basics of growing hydroponically before experimenting.

However a lot of off the shelf hydroponic nutrients can be expensive, costing upwards of $0.30 +cents per gallon of nutrient solution, or more. But there are nutrient manufactures that sell cost effective nutrients. Even down to as low as less than 2 cents per gallon of nutrient solution. We have a list of some of these cost effective nutrient manufactures for you. Feel free to contact us if you know of more we can add to the list so we can share them as well.

Nutrients are one of the basics of any hydroponic system. In order for a fertilizer to be incorporated into a hydroponic system it must be soluble in water. If not, the plant cannot access it. With Hydroponics the grower has complete control over the implementation of fertilizer, regarding type and concentration. They also have the ability to immediately monitor and maintain a relative consistency, provided a nutrient meter is available. The composition of the nutrients is important and there are over twenty elements that are needed for a plant to grow. Carbon, hydrogen and oxygen are absorbed from the air and water.

The rest of the elements, called mineral nutrients, are dissolved in the nutrient solution and need to be in the correct ratios. Any good Hydroponic nutrient should contain all of these elements; Nitrogen (N), Potassium (K), Phosphorous (P), Calcium (Ca),Magnesium (Mg), Sulphur (S), Iron (Fe), Manganese (Mn), Copper (Cu), Zinc (Zn),Molydenum (Mo), Boron (B), Chlorine (Cl). For the most part, this is taken care of with any pre-formulated commercial hydroponic nutrients. Often, these pre-made nutrients come in 1, 2, 3, or even more “parts” so the grower can change the ratio of the mineral elements to allow for either vegetative or fruiting and flowering growth, or for different crops. It is best for the beginner to just fallow the general directions before experimenting with changing the ratios.

Be sure to use nutrients designed for Hydroponics in a Hydroponic system. The composition of elements in nutrients designed for soil are very different from that for Hydroponics because soil grown plants get most of these elements from the soil. With Hydroponics there is no soil to get the elements from, so the two are very different in composition because they are not designed to be a complete plant food and they may not water-soluble. For example, Nitrogen in the form of urea is not immediately available to a plant in hydroponics because urea is not soluble in water. For this reason Nitrogen must be delivered in its Nitrate form in order to be utilized in hydroponics.

One thing that is often over looked when it comes to nutrients is the temperature. The roots of plants grow underground in nature and to duplicate what they would receive in nature it is very important to keep the root zone to 68-72 degrees. That's not to say if the nutrient temp reaches 73 or 74 the plants will die, but it should be kept as close to 68-72 degrees as you can. Plants with nutrient tempters too high can have problems including (but not limited to) flowers turning yellow and falling off, damaged fruits and a lack of new growth.

pH/TDS/PPM levels for Hydroponic plants

The pH scale is a way to measure the Acid or Basic (alkaline) in nutrient solution. The official definition of pH is: a unit of measure that describes the degree of acidity or alkalinity of a liquid solution. It is measured on a scale of 0 to 14. Acids are in a range from 0 to 7, with lower numbers being a stronger acid. Alkaline is in the range from 7 to 14, with the higher numbers being a stronger base.

The pH of the nutrient solution is essential to the plants hearth because it will affect how well each element can pass through the root cell wall and nourish the plant. When the pH of the nutrient solution is out of balance the plants are not able uptake the nutrients in the water, basically starving them, even when there is plenty of food.

The pH requirements for plants are not the same for all plants and you should not grow plants with different pH requirements in the same nutrient solution. You will wind up feeding one plant and starving the other, no mater what pH level you keep it at.

We have listed some plant requirements and categorized them by Fruit, Vegetables,Herbs and Flowers for your convenience. Exact plant requirements can very depending on many variables, so it is much more important to be in the ballpark rather than on the decimal point in regards to pH.

Measuring and adjusting the pH of your nutrient solution is quite simple to do, but should be done daily to insure a constant pH level. Testing can be done inexpensively (under $10) using a pH testing kit that generally consist of a small vial that you put some of the solution in. Then you just add some drops to it and shake it up and compare the resulting color to a color chart to get the results. Also you can use pH testing strips. They work basically the same but it's a small strip of paper you dip in the nutrient solution then compare to the color chart.

If you are looking to be more accurate you can use a pH testing meter. They are electronic and measures down to the decimal point. These pH testing meters can vary in price but are usually under $100.

When measuring the pH you want to mix your nutrients with the water completely first to ensure a true reading. If the reading is not at the proper level you need to adjust it using pH adjusters called "pH up" and "pH down," Depending on weather your reading is to high or to low. If it's too high use the pH

down, and if it's too low use the pH up. The pH adjusters can come in a dry or liquid form, either will work fine but make sure you mix it completely before taking another reading. The adjusters vary in price depending on manufacture but are not that expensive

Artificial lighting for Hydroponic Plants

Metal Halide Bulbs Many gardeners recommend metal halide grow lights above all others. The reason being it's excellent spectral distribution. Metal halide bulbs emulate bright summer sunlight and contain all the energy peaks at wavelengths of the visible spectrum. To plants this means quality simulated sunlight and photosynthesis at a level much higher than that which fluorescent lamps can achieve.

Also, metal halide grow lights have good lumen maintenance and long life expectancy. Having good lumen maintenance means that as a lamp ages, its decline in lumen output is very gradual. After 12 months of use at 18 hours per day, a 1000 watt metal halide lamp should be replaced as it is only about 85% as bright as the day you bought it. Halide is the best bulb technology available for achieving the highest level of plant and flower growth. They allow the flexibility of multi-crop, multi-season indoor gardening.

High Pressure Sodium Bulbs (HPS) growlights are the only growlights comparable to metal halide bulbs. They have good spectral distribution, but sodium lights cannot compare to halide in the blue end of the spectrum. Just in the same way, Metal Halide lights can’t compete with Sodiums in the red end of the spectrum.

Sodium grow lights are particularly high in the yellow and red regions of the spectrum. This is the type of light fruiting and flowering plants like best. Because of the focus on red light, some varieties of plants grown with sodium lights alone can become elongated and leggy.

Sodium grow lights do, on the other hand, stimulate flower and fruit production more efficiently than metal halide bulbs, making them an important light source best used in conjunction with metal halide either in addition to, or cycled together. High Pressure Sodium bulbs also have a much longer life expectancy than metal halides, lasting up to two (2) years!

LED Grow Lights Plants seem respond to LED lights similar to T5 fluorescent fixtures. They result in tight inter-nodal growth, and short stocky, strong plants. The plants do look a little different - the leafs tend to curl down. But the leaves are thicker and a more healthy shade of green. Vegetative growth is a little slower compared to a 400 watt HPS light but are healthy and progress normally.

Fruiting and flowering is also slightly slower but healthy and strong, with surprisingly dense development. The fruit and flowers are more realistic in color and are beautiful. One LED UFO will come very close to the best results you could achieve with a 400 watt HPS and it uses only 1/4 of the electricity, plus it doesn't generate any heat. LED's are NOT the best choice for really big plants, or

anyone that wants a seriously productive garden, but for a nice hobby garden (or heat-free summer garden), they work really well.

High Output Fluorescents T5 high output fluorescent tubes produce very little heat which lets you position them closer to your plants to raise the light levels. T5 high output fluorescents are great for seedlings and cloning! T5 high output fluorescents put out 5000 lumens per tube and have solid state electronic ballasts that do not emit heat, noise or vibration.

Compact Fluorescent lights (CFL's) work best in small spaces as they do not produce much heat or use much electricity. For fruiting or flowering plants, the 2700K warm bulb is best. For plants taller than a foot, regular fluorescent tubes can be supplemented on the plant sides. (Note: When using CFL's you should remember to use the actual wattage NOT their wattage equivalents when calculating how many watts you need for your hydroponic system.)

Growing Mediums and Hydroponics

In hydroponics, the growing medium takes the place of the dirt/soil. Not to provide nutrients, but so the roots can support the plants weight and hold it upright. Just about any inert material can be used as a growing media. Inert meaning that it cant/wont decay or break down quickly, thus providing nutrients to the plants. Hydroponic growing media is simply a soil-less material that is generally porous so it can hold the moisture and oxygen that the root system requires to grow. Non porous materials can be used

as well, but watering cycles would need to be more frequent so the roots don't dry out between watering's. See the List of different types of growing media for hydroponics

The growing medium won't be able to grow anything on its own. If you placed plants in hydroponic growing media, and watered it with plain water, the plants would starve from nutrient deficiency. It's simply there to help support the plants weight as well as the moisture and oxygen the roots need. The nutrients the plants need are provided by the nutrient solution, and is what the growing media is watered and moistened with.

Some of the most widely used growing media's include Rockwool, Lightweight Expanded Clay Aggregate (called, Hydrocorn or Grow Rock), Coconut Fiber/Coconut chips, and Perlite or Vermiculite. While there are a lot of materials that can be used as growing media in hydroponics, they can all have very different property's than another type of media. We have even seen the use of hay bales as growing medium to grow tomatoes, using a drip lines on top to drip the nutrient solution onto the hay bales and tomato plant roots.

There isn't one growing media that is better than the rest. Especially with so many different hydroponic system designs possible. However many growers eventually favor one type over others. There are a lot of things to consider when choosing what to use as a growing media. The type of system your growing in, and how you design and build that system is the biggest factor.

While there is no one best growing media for all situations, some growing media's work better than others in different systems. With any hydroponic system, and/or any type of growing media, the goal is still the same. You just need the roots to be moist, not soggy and saturated. If the growing media is saturated and soggy, the roots will suffocate from lack of oxygen. That situation can easily lead to roots dying, and root rot.

Things to consider about growing media foreach type of hydroponic system

Drip systemsDrip systems are fairly easy to control moisture in. As long as you design it so it has good drainage, and limit water pooling at the bottom you should be able to keep your growing media from being too soggy. We like to use river rock at the bottom to aid drainage, and keep the growing media from sitting in a pool of water at the bottom.

NFT systemsNFT systems use a very shallow, but continuous stream of water at the bottom of a channel where the roots wick up moisture. Most NFT systems either use small starter cubes or small 1 inch baskets, then let the roots just hang down into the flowing water. If these cubes or baskets are to close to the water supply, and your growing media can become saturated easily, that combination can lead to "stem rot" if the growing media around the stem is always saturated.

Ebb-Flow (flood and drain) systems Flood and drain systems can vary quite a bit in design. But generally you would want to stay away from any growing media that floats like Perlite and Vermiculite. Each time the system cycles on for the flooding stage the growing media will become weightless, then your plants will loose all their support and want to tip over. Depending on your system you could lower the flood level so floating is minimal, as long as the root-ball can still get plenty of moisture and you don't loose much plant support. Plant support may not be as much of a factor if growing vine type plants like tomato's, peas or melons that would be tied to a trellis as well.

Also with flood and drain systems, and depending on the type of growing media you choose, you want to make sure you have good drainage so that the growing media isn't continually saturated. Grow rocks won't wick up much moisture, but we like using coco chips a lot because they are inexpensive, but coco chips wick up water if they are sitting in it. So a layer of river rock at the bottom keeps it from sitting in the water.

Water culture systemsWater culture systems don't generally use much if any growing media because it is designed so the plants roots are submerged into the nutrient solution itself. So plants are generally started using small starter cubes or small baskets. Starter cubes typically are suspended above the water line, while baskets can suspended either just above or just below the water line. The growing media you choose and how much it absorbs moisture will make a difference. You don't want it to become saturated, you just want it to be moist at the bottom, the top should be dry. The roots will grow downward into the nutrient solution.

Now you may be wondering if it's so bad if the growing media becomes saturated, why won't the roots become suffocated if their under water all the time in a water culture system. First not all plants do well in water culture systems. Second and most important, a water culture system uses an air pump to generate a lot of air bubbles to the roots under water. The plants get oxygen from these air bubbles directly, as well as the air bubbles increase the dissolved oxygen levels in the water itself.

Aeroponic systemsAeroponic systems typically don't use much growing media at all. Aeroponic systems are designed to allow the roots hang in the air while getting frequently getting misted with nutrient solution so the roots don't dry out. Seeds are started in either small starter cubes small baskets, then when their big enough their planed in the aeroponic system. You'll want to make sure the cubes or growing media in the baskets don't become saturated. While almost all the roots will be hanging in air with no chance of becoming suffocated, wet growing media around the plants steam can lead to "stem rot."

Wick systemsWick systems are the least used type of system, but with no moving parts, motors or pumps, they rely on wicking up moisture into the growing media and to the plants roots through a piece of fabric. With wick systems you'll want to use a growing media that absorbs and holds onto moisture easily. You can control the amount of water getting to the plant by using a larger/wider wick, or more than one.

List of different types of growing media for hydroponics

Rockwool

Rockwool is one of the most common growing media's used in hydroponics. Rockwool is a sterile, porous, non degradable medium that is composed primarily of granite and/or limestone which is super heated and melted, then spun into a small threads like cotton candy. The rockwool is then formed into blocks, sheets, cubes, slabs, or flocking. Rockwool sucks up water easily so you'll want to be careful not to let it become saturated, or it could suffocate your plants roots, as well as

lead to stem rot and root rot. Rockwool should be pH balanced before use. That's done by soaking it in pH balanced water before use.

Grow Rock (Hydrocorn)

Grow rock is a Lightweight Expanded Clay Aggregate (L.E.C.A.), That is a type of clay which is super-fired to create a porous texture. It's heavy enough to provide secure support for your plant's, but still light weight. Grow rocks are a non-degradable, sterile growing medium that holds moisture, has a neutral pH, and also will wick up nutrient solution to the root systems of your plants. Hydrocorn grow media is reusable, it can be cleaned, sterilized, then reused again. Although on a large scale, cleaning and sterilizing large amounts of grow rocks can be quite time consuming. Grow rock is one of the most popular growing medium used for hydroponics, and just about every store selling hydroponics supplies carries it.

Coco Fiber Coco Chips

"Coco coir" (Coconut fiber) is from the outer husk of coconuts. What was once considered a waste product, is one of the best growing mediums available. Although coco coir is an organic plant material, it breaks down and decomposes very slowly, so it won't provide any nutrients to the plants growing in it, making it perfect for hydroponics. Coco coir is also pH neutral, holds moisture very well, yet still allows for good aeration for the roots. Coco fiber comes in two forms, coco coir (fiber), and coco chips. Their both made of coconut husks, the only difference is the particle size. The coco fiber particle size is about the same as potting soil, while the coco chips particle size is more like small wood chips.

The larger size of the coco chips allows for bigger air pockets between particles, thus allowing even better aeration for the roots. Also if your using baskets to grow your plants in, the chips are to big to fall through the slats in the baskets. Both the fiber and chips come in compressed bricks, and once soaked in water it expands to about 6 times the original size. Coco fiber does tend to color the water, but that diminishes over time. And you can leach out most of the color if you soak it in warm/hot water a few times before use.

Perlite

Perlite is mainly composed of minerals that are subjected to very high heat, which then expand it like popcorn so it becomes very light weight, porous and absorbent. Perlite has a neutral pH, excellent wicking action, and is very porous. Perlite can by used by itself, or mixed with other types of growing media's. However because perlite is so light that it floats, depending on how you designed your hydroponic system, perlite by itself may not be the best choice of growing media for flood and drain systems.

Perlite is widely used in potting soils, and any nursery should carry bags of it. However perlite is sometimes also used as an additive added to cement. You may find it for a better price with the building supply's, and/or at places that sell concrete mixes and mixing supply's. When working with perlite be careful not to get any of the dust in your eyes. Rince it off to wash out the dust, and wet it down before working with it to keep the dust from going airborn.

Vermiculite

Vermiculite is a silicate mineral that like perlite, expands when exposed to very high heat. As a growing media, vermiculite is quite similar to perlite except that it has a relatively high cation-exchange capacity, meaning it can hold nutrients for later use. Also like the perlite, vermiculite is very light and tends to float. There are different uses and types of vermiculite, so you'll want to be sure what you get is intended for horticulture use. The easiest way to be sure is to get it from a nursery.

Oasis Cubes

Oasis Cubes are similar to Rockwool cubes, and have similar property's. But oasis cubes are more like the rigid green or white floral foam used by forests to hold the stems in their flower displays. Oasis cubes are an open cell material which means that the cells can absorb water and air. The open cells wick moisture throughout the material, and the roots can easily grow and expand through the open cell structure. While oasis cubes are usually used as starter cubes for hydroponically grown plants, they also have bags you can fill your growing containers with. While oasis cubes are similar to rockwool, Oasis cubes don't become waterlogged as easily as rockwool cubes. Even so don't let it stay in constant contact with the water supply, or you'll still have water logging issues.

Floral foam

Floral foam can be used as a growing media in hydroponics as well, and is similar to the oasis cubes, though the cell size is larger in the floral foam. Depending on the type of hydroponic system your using, and how you designed it, you may notice a couple of problems with using floral foam. First it can crumble easily and that can leave particles in your water. Second you'll want to be sure it doesn't get water logged. Floral foam absorbs water easily, so make sure it isn't in constant contact with the water supply.

Growstone Hydroponic Substrate

Growstones are made from recycled glass. They are similar to grow rocks (hydrocorn) but are made of clay and shaped marbles. Growstones are light weight, unevenly shaped, porous, and reusable, they provide good aeration and moisture to the root zone. They have good wicking ability and can wick water up to 4 inches above the water line. So you'll want to make sure it has good drainage or is deep enough so it doesn't wick water all the way to the top. Otherwise like with the growing media in any hydroponic system, if the top of the growing media is continually wet, you may have problems with stem rot. While they are made from recycled glass, their not sharp and you wont get cut from it, even if they break.

River rock

River rock is common and easy to find in home improvement stores, as well as even pet supply's stores (with the fish and aquariums). River rock is fairly inexpensive (depending on where you get it from), and comes in many different sizes. River rock is rounded with smooth edges from tumbling down the river. Though manufactured river rock is rounded using large mechanical tumblers, it has the same end result with smooth edges.

You can use regular rocks from your back yard in hydroponic systems as well if you don't mind the jagged edges. Just make sure to clean and sanitize them before using it. Just spray all the dirt off of the rock using the jet spray from your hose to clean it, then soak it overnight in bleach water to sanitize it. Then just rinse and use. Though using rock as a growing media is inexpensive and easy, it will get heavy quickly, so you wont want to move it later.

River rocks are not porous, therefor it doesn't hold and retain moisture in the root zone of hydroponic

systems. Rock is uneven so it has a lot of air pockets between the rocks so the roots can get plenty of oxygen, but water easily drains down to the bottom. Rock won't wick up moisture either, so you will need to adjust your watering schedules so the roots don't dry out between watering's. You can mix in some coco chips or other growing media that holds moisture with your rock to aid it in holding onto moisture longer.

Because of the good drainage property's of rock, it's very good to use to aid in the drainage of other hydroponic growing media's that might otherwise become saturated from sitting in water. A layer of rock at the bottom of the growing container will keep your growing media from sitting in water at the bottom of the container, keeping it from being saturated.

Pine shavings

Pine shavings are an inexpensive hydroponic growing media as well, and a lot of commercial growers use it. Generally for large scale hydroponic drip irrigation systems. Don't confuse pine shavings with saw dust. Saw dust will become compact and water logged easily. You'll want to make sure your pine shavings were made from kiln dried wood, and does "NOT" contain any chemical fungicides. Kiln dried to burn off all the sap in the wood that is bad for the plants. Most pine shaving products would be kiln dried to begin with.

Good source to find pine shavings are pet supply stores. Its used for things like hamster and rabbit bedding. Just make sure to read the package to be sure it doesn't have any chemical additives like fungicides or odor inhibitors. You should be fine if it states it's organic. Another good cheep source for pine shavings is at feed stores, it's also used as bedding in horse stalls and they sell it by cubic yard. If you have a choice get the largest partial size you can. The larger the air pockets between the shavings, the better aeration to your roots.

Pine shavings are a wood product, so they absorb water easily, thus can become water logged easily. So make sure you have good drainage so the shavings don't sit in water. If there is a possibility of it sitting in water, a layer of rocks at the bottom will aid drainage greatly.

Composted and aged Pine bark

Pine bark is one of the first growing media's used in hydroponics. It was generally considered a waste product, but has found uses as a ground mulch, as well as substrate for hydroponicaly grown crops. Pine bark is considered better than other types of tree bark because it

resists decomposition better, and has less organic acids that can leach into the nutrient solution than others. Bark is generally referred to as either fresh, composted, or aged.

Fresh bark uses up more nitrogen as it begins to decompose, so commercial growers generally compensate by adding extra nitrogen to the nutrient solution. During the composting process, nitrogen is added to the bark, and mixing it in while breaks down. So nitrogen issues are far less of a concern with composted pine bark. Ageing is a similar process, but has less nitrogen added to it, so it's better than using fresh bark, but not as easy as the composted bark. Pine bark can be found at places that sell ground mulch, as well as ground mulch for playgrounds.

Poly (Polyurethane) foam insulation

Polly foam is not commonly used in hydroponics, and hydroponics stores don't carry it. But has been used as an alternative to using rockwool or oasis cubes as starter cubes with great results. Polly foam is cheap and easy to find. Any hobby store or place that sells fabrics should carry it. It's most commonly used as furniture foam, and is also referred to as "foam batting." It comes in sheets or rolls of different sizes and thickness. You can make your own starter cubes for about one penny each using the poly foam if you get the one or two inch thick sheets/rolls and cut them into cubes.

Water absorbing crystals (water-absorbing polymers)

Water absorbing polymer crystals have been around for quite a while, and are used in many industry's. Everything from baby diapers, to the sports industry where they are used in cloth rags they can where on the head or neck to keep cool. They are also used in gardening where the crystals are mixed into the soil to help retain moisture in the soil. Florists use them in vases to keep flowers fresh, and the colored ones make for a nice decorated display.

The crystals expand to many times their size as they soak up water. One pound of the crystals can hold as much as 50 gallons of water. The crystals come in many sizes, everything from a powder, to marble and even golf ball size. Depending on the size of the crystals they can take more than an hour or two to fully absorb. When they are full of water they look and feel like a glob of jello. Once they dry out, they can be stored and reused again over and over.

The water absorbing polymer crystals are not a common hydroponic growing media, but like everything else, it's growing in popularity. Mostly due to their increased availability. They are quite inexpensive, and reusable. However used alone by themselves they don't allow the roots to get much oxygen/air. Being

like jello they pack together and fill the air pockets. The larger size crystals are better suited for use in hydroponics. The larger size helps retain some of the air pockets between the crystals. Also by mixing some river rock or other similar growing media with the crystals will help increase the air pockets between the crystals.

Using the polymer crystals for hydroponics allows for some of the simplest hydroponic system designs. Even on the slimmest of budgets. Simply soaking some water absorbing crystals in nutrient solution, then setting them in a container and placing your seedling's in it, you've got a hydroponically grown plant. You don't need any pumps. Just make sure there are holes in the bottom of your container, and just place your container in nutrient solution once or twice a week to re-hydrate the crystals.

You won't find water absorbing polymer crystals in hydroponic shops, but they are easy to find. Because of their popularity, most large nursery's carry them as soil amendments. Also if you do a search for them online, you'll fine hundreds of places selling them.

Sand

Sand Is actually a very common growing media used in hydroponics. It's the main growing media used at the Epcot Center Hydroponic Greenhouse in Florida. Mainly for their large hydroponically grown plants and trees. Sand is like rock, just smaller in size. Because the particle size is smaller than regular rock, moisture doesn't drain out as fast. Sand is also commonly mixed with Vermiculite, Perlite, and or coco coir. All help retain moisture as well as help aerate the mix for the roots.

When using sand as a growing media you will want to use the largest grain size you can get. That will help increase aeration to the roots by increasing the size of the air pockets between the grains of sand. Mixing Vermiculite, Perlite, and or coco coir with the sand will also help aerate. You will also want to rinse the sand well before use to get as much of the dust particles out of it as you can. One big downside to using sand as a growing media for hydroponics is that it is very heavy. 3-4 gallons of wet sand can weigh up to 50lbs. So you won't want to be moving it once you get it set up. Or use it in a ratio of something like 20%-30% sand and the rest Vermiculite, Perlite, or another type of growing media to reduce weight.

Rice Hulls

Depending on your location, rice hulls may be readily available. It's a byproduct of

the rice industry. Even though they are an organic plant material, they break down very slowly like coco coir, making them suitable as a growing media for hydroponics. Rice hulls are referred to as either fresh, aged, composted and parboiled, or carbonized. Fresh rice hulls are typically avoided as a hydroponic growing media because of the high probability of contaminants such as rice, fungal spores, bacteria, decaying bugs, and weed seeds. Parboiled rice hulls (PRH) is done by stemming and drying the rice hulls after the rice has been milled from them. This kills any spores, bacteria, and microorganisms, leaving a sterile and clean product.

Rice hulls are also often used as part of a mix of growing media such as 30%-40% rice hulls and pine bark mix. The overall pH of parboiled and composted rice hulls range from 5.7 to 6.5, which is right in the pH range for most hydroponically grown plants. Fresh and/or composted rice hulls tend to have a high Manganese (Mn) content. But problems with Manganese toxicity can be avoided as long as the pH is above 5. Which is below normal range for hydroponics anyway.

Nutrients for Hydroponic Systems

Why and when to test and adjust pH in hydroponics

pH test kits versus electronic pH test meters

Using pH adjusters

Pump timers

When you need to use timer for the water pump

How often to water the plants in your hydroponic systems

Water level in your hydroponic system

What size reservoir to use in your hydroponic system

Water quality

Artificial lighting used for hydroponics

Water Temperatures and Oxygen for the roots

Nutrients for Hydroponic Systems

Hydroponic nutrients are different than nutrients for growing plants in soil. Soil nutrients don't contain all the micro-elements the plants need. They don't because the micro-elements are in abundance in the soil, so there not added to nutrients designed for soil grown plants. You'll need nutrients designed for

growing plants in hydroponic systems. There are many brands and types on the market to choose from, and most are just over priced. While liquid fertilizers tend to be easier to use, dry fertilizers are much cheaper to use because your not paying for the to ship all that water in the liquid fertilizers to the stores. For more information about finding economical hydroponic nutrients, and hydroponic nutrients in general, visit this page; Nutrients for Hydroponic systems

Why and when to test and adjust pH in hydroponics

The plants can only absorb the nutrients in your hydroponic nutrient solution if the pH of that nutrient solution is within a range the plants can use. If the pH is out of that range, it won't mater how good your nutrient solution is, the plants will still suffer from malnutrition. You should also test pH daily until you are familiar with how it can change.

pH Test Kits versus Electronic pH test Meters

There are many different electronic pH test meters on the market. However good electronic pH test

meters expensive and often wind up giving you false readings, even if they are calibrated often and stored properly. General Hydroponics makes very good pH drops (pictured right).

The pH test drops wont give you false readings, they don’t need to be calibrated, you don't need to buy calibration fluid for pH drops, don't need special care to store properly, and only cost between $6 and $8 depending on where you get them. Even of you buy an electronic pH test meter, make sure to have some pH test drops on hand so you can verify the readings your electronic test meter is giving you if there is any question about it's accuracy.

Most hydroponic supply stores will want to sell you the electric meters, and do so saying that they are more accurate, or the pH drop kits are hard to read. But the truth is you simply don't need to measure the pH down to the nearest tenth of a point. And they are very easy to read the results. The plants just need to be within a range like 5.5 to 6.5, not down to a specific tenth like 6.2. The drops will last a long

time as well, they don't expire. The directions say to fill the vile ½ way and add 3 drops. But if you just fill the vial about ¼ inch and use just one drop, you'll get the same color, and they’ll even last three times longer.

pH adjusters

pH adjusters are what you will need to adjust the pH if it isn’t within range. Make sure you get pH adjusters designed for hydroponics. Don't try using pH adjusters for soil, or household products like white vinegar or backing soda. Anything other than pH adjustors designed for hydroponics wont be stable, and constantly adding different things to your nutrient solution is a bad thing. For a list of pH ranges for different types of plants visit these pages:

Fruit RequirementsVegetable RequirementsHerb RequirementsFlowering plant Requirements

Fruit Requirements

The pH and electro-conductivity values specified here are given as a broad range. It should be noted that specific plant requirements will vary according to regional climatic conditions, and from season to season within that region. These values are intended for Hydroponic plants only (soil grown plants will differ). Electro-Conductivity (EC) or Conductivity Factor (cF) can be expressed as either milliSiemens (mS), cF, or parts per million (PPM) 1 mS = 10cF = 700ppm.

Fruit

Plants pH cF EC PPM

Banana 5.5-6.5 18-22 1.8-2.2 1260-1540

Black Currant 6.0 14-18 1.4-1.8 980-1260

Blueberry 4.0 -5.0 18-20 1.8-2.0 1260-1400

Melon 5.5-6.0 20-25 2.0-2.5 1400-1750

Passionfruit 6.5 16-24 1.6-2.4 840-1680

Paw-Paw 6.5 20-24 2.0-2.4 1400-1680

Pineapple 5.5-6.0 20-24 2.0-2.4 1400-1680

Red Currant 6.0 14-18 1.4-1.8 980-1260

Rhubarb 5.0- 6.0 16-20 1.6-2.0 840-1400

Strawberries 5.5-6.5 18-22 1.8-2.2 1260-1540

Watermelon 5.8 15-24 1.5-2.4 1260-1680

As a general rule, plants will have a higher nutrient requirement during cooler months, and a lower requirement In the hottest months. Therefore, a stronger nutrient solution should be maintained during winter, With a weaker solution during summer when plants take up and transpire more water than nutrients.

Vegetable Requirements

The pH and electro-conductivity values specified here are given as a broad range. It should be noted that specific plant requirements will vary according to regional climatic conditions, and from season to season within that region. These values are intended for Hydroponic plants only (soil grown plants will differ). Electro-Conductivity (EC) or Conductivity Factor (cF) can be expressed as either milliSiemens (mS), cF, or parts per million (PPM) 1 mS = 10cF = 700ppm.

Vegetables

Plants pH cF EC PPM

Ambra radicchio 5.5-6.5

Artichoke 6.5-7.5 8-18 0.8-1.8 560-1260

Asparagus 6.0-6.8 14-18 1.4-1.8 980-1260

Bean (Common) 6.0 20-40 2-4 1400-2800

Beans (Italian bush) 6.0-6.5

Beans (Lima) 6.0-6.5

Beans (Pole) 6.0-6.5

Beetroot 6.0-6.5 8-50 0.8-5 1260-3500

Broad Bean 6.0-6.5 18-22 1.8-2.2 1260-1540

Broccoli 6.0-6.5 28-35 2.8-3.5 1960-2450

Brussell Sprout 6.5-7.5 25-30 2.5-3.0 1750-2100

Cabbage 6.5-7.0 25-30 2.5-3.0 1750-2100

Capsicum 6.0-6.5 18-22 1.8-2.2 1260-1540

Carrots 6.3 16-20 1.6-2.0 1120-1400

Cauliflower 6.0-7.0 5-20 0.5-2.0 1050-1400

Celery 6.5 18-24 1.8- 2.4 1260-1680

Collard greens 6.5-7.5

Cucumber 5.8-6.0 17-25 1.7-2.5 1190-1750

Eggplant 5.5-6.5 25-35 2.5-3.5 1750-2450

Endive 5.5 20-24 2.0-2.4 1400-1680

Fodder 6.0 18-20 1.8-2.0 1260-1400

Garlic 6.0 14-18 1.4-1.8 980-1260

Leek 6.5-7.0 14-18 1.4-1.8 980-1260

Lettuce 5.5-6.5 8-12 0.8-1.2 560-840

Marrow 6.0 18-24 1.8-2.4 1260-1680

Okra 6.5 20-24 2.0-2.4 1400-1680

Onions 6.0-6.7 14-18 1.4-1.8 980-1260

Pak-choi 7.0 15-20 1.5-2.0 1050-1400

Parsnip 6.0 14-18 1.4-1.8 980-1260

Pea 6.0-7.0 8-18 0.8-1.8 980-1260

Peas (Sugar) 6.0-6.8

Pepino 6.0-6.5 20-50 2.0-5.0 1400-3500

Peppers 5.8-6.3 20-30 2.0-3.0 1400-2100

Bell peppers 6.0-6.5 20-25 2.0-2.5 1400-1750

Hot Peppers 6.0-6.5 30-35 3.0-3.5 2100-2450

Potato 5.0-6.0 20-25 2.0-2.5 1400-1750

Pumpkin 5.5-7.5 18-24 1.8-2.4 1260-1680

Radish 6.0-7.0 16-22 1.6-2.2 840-1540

Spinach 5.5-6.6 18-23 1.8-2.3 1260-1610

Silverbeet 6.0-7.0 18-23 1.8-2.3 1260-1610

Sweet Corn 6.0 16-24 1.6-2.4 840-1680

Sweet Potato 5.5-6.0 20-25 2.0-2.5 1400-1750

Swiss chard 6.0 6.5

Squash (Summer) 5.0-6.5

Squash (Winter) 5.0-6.5

Taro 5.0-5.5 25-30 2.5-3.0 1750-2100

Tomato 5.5-6.5 20-50 2.0-5.0 1400-3500

Turnip 6.0-6.5 18-24 1.8-2.4 1260-1680

Zucchini 6.0 18-24 1.8-2.4 1260-1680

As a general rule, plants will have a higher nutrient requirement during cooler months, and a lower requirement In the hottest months. Therefore, a stronger nutrient solution should be maintained during winter, With a weaker solution during summer when plants take up and transpire more water than nutrients.

Herb Requirements

The pH and electro-conductivity values specified here are given as a broad range. It should be noted that specific plant requirements will vary according to regional climatic conditions, and from season to season within that region. These values are intended for Hydroponic plants only (soil grown plants will differ). Electro-Conductivity (EC) or Conductivity Factor (cF) can be expressed as either milliSiemens (mS), cF, or parts per million (PPM) 1 mS = 10cF = 700ppm.

Herbs

Plants pH cF EC PPM

Basil 5.5-6.5 10-16 1.0-1.6 700-1120

Chicory 5.5-60 20-24 2.0-2.4 1400-1600

Chives 6.0-6.5 18-22 1.8-2.4 1260-1540

Fennel 6.4-6.8 10-14 1.0-1.4 700-980

Lavender 6.4-6.8 10-14 1.0-1.4 700-980

Lemon Balm 5.5-6.5 10-16 1.0-1.6 700-1120

Marjoram 6.0 16-20 1.6-2.0 1120-1400

Mint 5.5-6.0 20-24 2.0-2.4 1400-1680

Mustard Cress 6.0-6.5 12-24 1.2-2.4 840-1680

Parsley 5.5-6.0 8-18 0.8-1.8 560-1260

Rosemary 5.5-6.0 10-16 1.0-1.6 700-1120

Sage 5.5-6.5 10-16 1.0- 700-1120

Thyme 5.5-7.0 8-16 0.8-1.6 560-1120

Watercress 6.5-6.8 4-18 0.4-1.8 280-1260

As a general rule, plants will have a higher nutrient requirement during cooler months, and a lower requirement In the hottest months. Therefore, a stronger nutrient solution should be maintained during winter, With a weaker solution during summer when plants take up and transpire more water than nutrients.

Flowering plant Requirements

The pH and electro-conductivity values specified here are given as a broad range. It should be noted that specific plant requirements will vary according to regional climatic conditions, and from season to season within that region. These values are intended for Hydroponic plants only (soil grown plants will differ). Electro-Conductivity (EC) or Conductivity Factor (cF) can be expressed as either milliSiemens (mS), cF, or parts per million (PPM) 1 mS = 10cF = 700ppm

Flowers

Plants pH cF EC PPM

African Violets 6.0-7.0 12-15 1.2-1.5 840-1050

Anthurium 5.0-6.0 16.20 1.6-2.0 1120-1400

Antirrhinim 6.5 16-20 1.6-2.0 1120-1400

Aphelandra 5.0-6.0 18-24 1.8-2.4 1260-1680

Aster 6.0-6.5 18-24 1.8-2.4 1260-1680

Begonia 6.5 14-18 1.4-2.4 980-1260

Bromeliads 5.0-7.5 8-12 0.8-1.2 560-840

Caladium 6.0-7.5 16-20 1.6-2.0 1120-1400

Canna 6.0 18-24 1.8-2.4 1260-1680

Carnation 6.0 20-35 2.0-3.5 1260-2450

Chrysanthemum 6.0-6.2 18-25 1.8-2.5 1400-1750

Cymbidiums 5.5 6-10 0.6-1.0 420-560

Dahlia 6.0-7.0 15-20 1.5-2.0 1050-1400

Dieffenbachia 5.0 18-24 1.8-2.0 1400-1680

Dracaena 5.0-6.0 18-24 1.8-2.4 1400-1680

Ferns 6.0 16-20 1.6-2.0 1120-1400

Ficus 5.5-6.0 16-24 1.6-2.4 1120-1680

Freesia 6.5 10-20 1.0-2.0 700-1400

Impatiens 5.5-6.5 18-20 1.8-2.0 1260-1400

Gerbera 5.0-6.5 20-25 2.0-2.5 1400-1750

Gladiolus 5.5-6.5 20-24 2.0-2.4 1400-1680

Monstera 5.0-6.0 18-24 1.8-2.4 1400-1680

Palms 6.0-7.5 16-20 1.6-2.0 1120-1400

Roses 5.5-6.0 15-25 1.5-2.5 1050-1750

Stock 6.0-7.0 16-20 1.6-2.0 1120-1400

As a general rule, plants will have a higher nutrient requirement during cooler months, and a lower requirement In the hottest months. Therefore, a stronger nutrient solution should be maintained during winter, With a weaker solution during summer when plants take up and transpire more water than nutrients.

Like with the nutrients, liquid pH adjustors are more expensive than the dry adjustors. Both General

Hydroponics and Earth Juice make very good andinexpensive dry adjustors. A little goes a long way. Depending on how much you grow and the water quality you use, one pound of the dry adjustors will probably last you between 6 months to 2 years. Make sure to get both pH up and pH down, even if you don't think you will need both. There will be times when you over adjust, and you'll need to bring the pH back the other way.

Pump Timers

For most hydroponic systems you will need a timer to run the water pump. A general purposes heavy duty (15 amp) light timer works fine. We recommend 15 amp timers because in our experience we have had the 10 amp timers burn out, and the 15 amp timers don't cost but a dollar or so more depending on where you get it. Manufactures generally call timers that can handle 15 amps “heavy duty.” Though it isn’t always necessary, we prefer to use indoor-outdoor timers as well, their grounded and help protect against electrical shorts. Basically their safer to use around water.

Also we would recommend using the less expensive dial (mechanical) timers, rather than the more expensive digital timers. Unless your digital timer takes a separate battery to hold memory when the power goes out. It's happened to us in the past when even a short 2 second power outage wipes out any memory in the digital timer, then nothing gets watered, even after the power comes back on. Besides the possible power outage, the same thing happens whenever you unplug it for any reason. Like just taking it into the other room to change the settings. Mechanical timers will just pick right back up when the power is restored, and don’t have memory to loose.

Not all timers are the same, make sure the one you get has many settings. Some timers come with only a few pins around the dial. That will severely limit your options for on/off cycles. We wouldn’t even consider a timer unless it has pins all the way around the dial like the one in the picture on the right. Preferably with 15 minute minimum on/off times rather than the more common 30 minute minimums. 30 minute minimum on/off time settings will usually be fine, but 15 minute minimums will give you more flexibility.

When you need to use timer for the water pump

You'll need a pump timer for any Ebb & Flow (Flood and Drain) system, Drip system, Aeroponic system, and sometimes some people use them in NFT systems as well. Water Culture systems use an air pump which is left running 24/7 (so no timer is used in water culture systems), and Wick systems don't use any pumps at all.

For Ebb & Flow, Drip, and NFT systems the general purposes heavy duty light timers are fine. While NFT systems don't use a pump timer by definition because the water is left continuously flowing through the system 24/7. Some growers still like to use timers in their NFT systems.

For aeroponic systems true aeroponic system uses high water pressure to spray a fine mist (around 60-90 psi), and a true aeroponic systems use a special type of timer called a “cycle timer” that is designed to go on and off frequently, the timer is usually set to a specific “cycle.” As an example, it might only be set to go on for 30 seconds, but set to spray the roots every 5 minutes. So the cycle would be 30 seconds on, and 5 minutes off, cycling on and off all 24 hours a day like that.

Most people use low pressure in their aeroponic systems. Mainly because it's much cheaper to use a low pressure pump. If your pump doesn’t have a psi rating, it's a low pressure pump. You still spray the roots with spray heads, however they are more like sprinkler heads, and the water droplet size is much larger because of the lower pressure. Although you can still use a cycle timer in a low pressure aeroponic system, a regular general purposes heavy duty light timer can work as well, as long as it has enough settings. Usually a timer with pins all the way around the dial, and with 15 minute on/off times. Then setting it for 15 min on and 15 off all day.

How often to water the plants in your hydroponic system

How often to water the plants in a hydroponic system is one of the most asked questions. But both the easiest and hardest question to answer at the same time. Simply because the only real specific answer to that question that fits every situation is the general rule of thumb, “long enough to get the roots wet, but not so long they suffocate.”

Everybody’s situation is different, as well as the type of system their growing in, how they built the system, type of growing media their using, how much of it, type of plants their growing, their temperature and humidity levels etc. etc.. There are just to many variables to give a one size fits all answer to that question, other than a general rule of thumb.

Most new growers tend to try and over-think how much to water their plants, and if they stick to the general rule of thumb (“long enough to get the roots wet, but not so long they suffocate”), they will be fine. That's why having a timer that gives you flexibility in your settings is beneficial.

If the growing media and roots seem to be getting to dry between watering, increase the frequency that you water them. If they always seem to be very wet, cut back on your watering times and see what happens. You can always increase or decrease it again. Every grower will quickly learn what's best for their situation, type of system their growing in, growing media, etc., as well as develop their own preferences. Plants are highly adaptable, so don't over-think it.

WateringHow often and how long to water is a good question, but has so many variables like air temperature, water temp, type of growing medium used, type of plants (do they mind wet feet), how big the plants are, humidity etc. etc. etc.. That there's simply no real straightforward answer, except to say the goal is to water long enough to get the roots (and growing medium) wet, but not so long that the roots suffocate from lack of air/oxygen. Also to water often enough that they never dry out. If you see sings of wilting they are either well past dry, or to wet and suffocating.

Basically speaking, the roots just need enough moisture that they can absorb enough water to support the plants foliage. Bigger plants need more moisture (because they have a lot more foliage to support). Plants growing in dry conditions use more water than those growing in more humid conditions. Some growing medias hold moisture much better than others, thus don't need to be watered as often etc. etc. etc.. So just keep the growing media moist/damp.

Depending on the time of year (daily highs and lows), for this system I let it water for 30 minutes on, and between one and two and a half hours off. Just check the moistness of the growing medium. You will probably want to try setting the timer for different settings to find what works best for your plants, as well as your local conditions. Watering at night (during hours of darkness) is not typically necessary, because plants only suck up water during light periods. But I typically water a couple of times during the night in any system anyway, just to keep things moist

Water level in your hydroponic system

The water level of your hydroponic system will vary depending on the type of system your growing in, as well as the type of growing media your using. The type of growing media makes a difference because some will absorb and hold moisture better than others. In any hydroponic system the goal is to keep the roots moist, but not let the stem stay wet so the plant develops stem rot.

Flood and Drain SystemsWith a flood and drain system where the water floods the plants container from the bottom, you generally want the water level to be about two inches below the top of the growing media when the system is flooded. If your using a growing media like rockwool that becomes saturated easily, you may want it even lower. Basically the very top of the growing media should be almost dry to avoid stem rot, but a couple inches down where the plants main root-ball is should be moist.

NFT Systems

NFT systems typically just run a continuous thin layer of water along the bottom of a trough or tube. Just a millimeter or two deep. But depending on how you set up your NFT system, type of plants, and if your using much growing media the, your water depth may vary. If the roots are able to wick up enough moisture to keep the growing media slightly moist, your fine. But if the the growing media is saturated, you may need to reduce the water flow through the tube/trough, or tilt it more to get the water to flow faster. Or even do something to keep the roots from blocking the water flow through the system.

Drip SystemsThe water depth in a drip system isn’t really a concern because the water is supposed to drip/trickle down from the top of the growing media to the bottom of the plant container, then back to the reservoir. So when working properly, the water never actually builds up in the plants growing container, the water just moistens the growing media as it drips downward.

But depending on how you designed your drip system, and if the roots begin to clog your drain lines, you may get water pooling in the bottom of the plants container or even overflowing because it can't drain back properly. Make sure you check your drain lines regularly for clogging roots. Especially when they get big, and unclog them before the roots can build up to much. Just a quick disconnect from the container, then cut and poke through the opening is all that's needed.

If your plants container is deep enough, an inch or so of water pooling in the bottom wont be a problem saturating the growing media. If your concerned about the growing media becoming saturated from pooling water, you can fill the bottom of the container with a couple of inches of river rock to aid drainage and keep it from touching the water in the bottom.

Water Culture systemsIn water culture systems the roots remain submerged under water 24/7, but not quite all of them. The baskets or cubes holding the plants are suspended above the water. Usually on floating Styrofoam rafts,

or through holes in a stationary lid of a container. In either case you want the basket positioned so the growing medium can wick up a little moisture so it remains slightly moist, but wont become saturated. So the type of growing media makes a big difference. The splashing of the air bubbles as they break the surface of the water sprays little water droplets on the bottom of the baskets/grow cubes. If you have enough air bubbles going, that should be enough to keep the bottom of most types of growing media moist without actually touching the water.

The underwater roots in water culture systems get oxygen from all the air bubbles from the air pump and air stones in two ways, that way they wont suffocate. Some of the fresh air bubbles will rise up through the roots as they rise to the top of the water, in doing so making direct contact with the roots as they do (the more the better). Also as the air bubbles rise, they transfer oxygen molecules directly into the water itself, called “dissolved oxygen” that the plants can absorb through roots as well.

Aeroponic systemsThe water level in aeroponic systems doesn’t really apply. Basically because the roots are hanging in mid air, and are never actually submerged. The timing of how frequently you water the roots so they never have a chance to dry out is what's important in aeroponic systems.

Wick SystemsWith wick systems the water level in the plants container doesn’t really apply, other than you always want the wick to be submerged in water. Moisture is wicked up into the plants growing container through a wick. Usually some type of felt fabric. The water never gets a chance to build up and saturate the growing media. But the moisture level in the growing media can be controlled. Simply by using a larger or smaller felt wick, or using more than one to get even more water to wick up. Also using a good moisture absorbing growing media like coco fiber or coco chips will aid in moisture retention in wick systems as well.

What size reservoir to use in your hydroponic system

Using the right size reservoir is very important to growing successfully in hydroponic systems. If your reservoir is to small, that could cause you a number of problems. So sizing a reservoir for the type of plants your growing, as well as how many your growing in your system is key. The general rule of thumb for smaller plants like lettuce or strawberry’s etc. is a minimum of ½ gallon of nutrient solution per plant in the system. For larger mid range size plants like herbs or bush varieties of peppers etc., a minimum of 1 to 1.5 gallons of nutrient solution per plant in the system. And for large plants like tomato’s, larger varieties of peppers, melons, cucumbers, squash etc., a minimum of 2.5 gallons of nutrient solution per plant in the system.

Now those are just minimum recommendations. We always try and double the minimum recommendations. You don't need to fill the reservoir all the way up while the plants are small, but you'll need the full water volume when the plants get bigger and begin to reach full size. Starting with a reservoir that will be big enough to begin with is much easier (and cheaper) than replacing one that is to

small with a bigger one later.

If your reservoir is to small for the plants as they get bigger, you'll wind up dealing with problems you don't need to. Problems like large pH swings, needing to replace water to your reservoir daily as the plants drink it up, constant nutrient concentration fluctuations, even temperature fluctuations. All of which can lead plant stress and deficiency’s.

Water Quality

Save yourself the potential for a lot of headaches, and use a good quality filtered water from the beginning. Don't underestimate the importance of the water quality you use for your hydroponic systems, it can make a big difference in the health of your plants. Tap water, well water, stream water, rain water all have the potential for problems. Even though water filtered through a water

softener is basically pathogen and bacteria free, as well as most of the dissolved minerals have been taken out. It has trace amounts of salt (sodium chloride) that is toxic to plants, even in trace amounts. Some plants will tolerate it better than others, but the salt will build up in your hydroponic systems over time.

Tap water can contain any number of chemicals, minerals, and even that can build up to toxic levels. It can even have pathogens and fungi spores in it. Using tap water cause many diseases, mineral toxicity, and wide pH swings. Rain water can contain all sorts of pathogens, bacteria, fungi, chemicals from smog,

and even salt from places near the ocean. Well and stream water not only can contain all kinds of unwanted minerals, but it also can contain a ton of microorganisms, soil borne diseases, bacteria and fungi etc. that you could introduce to your plants. Once you do they can be just about impossible to get rid of.

So do yourself a favor and start with a good quality filtered water to begin with. RO water would be the best choice. If you don't have a RO system, then invest in a good

water filtration system. You can even build your own filtration system like we did using the water filter canisters that take replaceable filter cartridges. We even added quick connect couplers to make it quick and easy to connect to the hose when we needed it.

If you do, make sure to have at least 3 filters. First, a sediment filter. Second, a activated charcoal filter, Third an "absolute one micron" filter (0.5 microns). The better filters you use, the better your water quality will be. If you cant afford a filtration system, you can buy water from the machines at the grocery

store. You don't know how often they change their filters and if they keep up the maintenance on them. But at least it went through a filtration system and better than the other options.

Artificial Lighting used for Hydroponics

If you cant grow your hydroponic plants in natural sunlight, you'll need artificial lighting to grow them. Electricity isn't free, so we try and use natural sunlight as much as possible. But if weather conditions, space issues etc.. prevent you from being able to do so, artificial lighting would be necessary. There are a wide variety of lighting available for hydroponic plants. Some being better for some plants, and other lighting better for others. But that's an entire subject all by itself, you can find out a lot more about artificial lighting types for hydroponics, as well as growing plants with them on our page lights for hydroponic plants.

Water Temperatures and Oxygen for the roots

The nutrient solution is more than just a simple mix of elements in water that feed the root systems. It's also part of the environment for the root system (root zone). The root system environment is just as important as the above ground environment of the foliage, if not even more important.

Along with the mineral elements, the nutrient solution will also contain microorganisms (both good and bad ones). They get in there both through the air, as well as from anything that has been placed in it that wasn't sterilized first, even from your hands. Microscopic microorganisms, bacteria, fungi spores etc. are on everything and in the air everywhere, and their just looking for a nice place to grow and multiply (like in your nutrient solution).

The optimum water temperature is between 68 and 72 degrees Fahrenheit. That's optimum, if it's a little above or below that you should still be fine. When the water (and root zone) temperature gets in the low 80's and higher, Some negative things begin to happen. Pathogens (bad microorganisms) like and thrive in warm water, then they begin to outnumber the good ones. Bacteria and fungi thrive in warm water as well. Another problem with high water temps is the plant itself begins to suffer from heat stress, and generally abort fruiting just trying to stay alive. Also the higher the water temperature, the less of an ability the water itself has to hold onto dissolved oxygen molecules. The plant needs to absorb these oxygen molecules for plant growth, as well not to suffocate. Especially important in water culture systems where the roots are submerged in the nutrient solution 24/7.

Using an aquarium air pump with the air stone in your nutrient solution can help in two ways. First it replaces the oxygen molecules that the plants absorb. The bigger the plant the more oxygen the plant absorb, and you can never get to much oxygen to the root systems. Second is that pathogens are reduced in the oxygen rich water, but beneficial microorganisms thrive.

Low water temperatures aren't as bad for your plants, but will stunt and slow the plants growth. Once the temp gets in the 50's it will become noticeable, and in the 40's the plants growth gets really slow. If your water temps are getting to low, you can use an aquarium heater to warm it up. But make sure it doesn't come in contact with a plastic surface or it could melt a hole in it, also make sure it remains submerged all the time. If not, the glass can crack and break.