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Cultural Practices and Cultivar Selections for Commercial
Vegetable GrowersBrad Bergefurd
OSU South Centers
Piketon, Ohio
Cultural Practices to Consider…
• Location• Soil types • Types of crops• Garden Layout
• Rotation of crops• Planting Methods• Weed Control• Pest Control
Location
• Near water supply for easy access
• Full sun- some plants will grow in shady areas (leafy greens, pumpkins)
• Away from trees- rob nutrients from veggies
• Flat land to prevent runoff and erosion
Soil Types
• Best garden soil is loam= equal amount of sand, silt, and clay– Good drainage so oxygen is available for roots– Organic matter to hold moisture and provide
plants with nutrients– pH range should be from 6.3-7.0 for most
veggies
Loam soil is ideal
Earthworms are a sign of good soil health
• Stimulate microbial activity
• Mix and aggregate soil • Increase infiltration • Improve water-
holding capacity • Provide channels for
root growth • Bury and shred plant
residue
Soil Management Practices…
• Clay Soils– Work up in the fall of the year– This allows drier soil in spring for earlier
planting– Prepare “raised beds” to plant early in season– Work manure, residue, and leaves into soil to
increase organic matter
Soil Management Practices…
• Sandy Soils– Best when planted with a fall cover crop, rye or
vetch and the worked in early spring– This adds organic matter– Helps to hold on to moisture and residual
nutrients– Soil tests should be done each year to
determine nitrogen, phosphorus, and potassium levels as well as pH level.
Soil Management Practices…
• pH is too high (alkaline)– Add sulfur to recommended amounts from soil
test
• pH is too low (basic)– Add lime to recommended amounts– How much to apply? Don’t guess soil test!– Beans, peas, onions require high pH levels
Feed the Soil• Plant get their essential nutrients from soil – either
mineral or from organic matter. Soil fauna is essential to this process;
• Plants don’t require a season’s worth of nutrients all at once, like we don’t eat all our meals at once;
• Synthetic fertilizers are typically salts, which dissolve rapidly in soil solution– Can aggravate a soil salinity problem;– Nutrients may be lost before plants use them;– Nutrient level fluctuation can negatively affect soil
microbial ecosystem.
Composting
Compost Ingredients
Get compost analyzed• Will need to know the elemental makeup of the
compost to determine amounts to use to meet the crop nutrient requirements
• Should be tested by a laboratory for moisture and nutrient content.
• Nutrient analysis should include: total nitrogen (N), ammonium-N, phosphate (P2O5), and potash (K2O).
• Accurate manure or compost analysis requires that a representative sample be submitted; so several subsamples should be collected and composited to make up the sample.
• If manure or compost is being purchased, request a nutrient analysis from the seller for N, P2O5, and K2O content.
Fertilizing• Plant Food Elements analysis is needed
(even for organic fertilizers)
N-P-KNitrogen % Phosphorus %
Potassium %
5-10-5
Fertilizing
• Why important to know % of elements?• For you know how much to feed your crops.• Like a diet calculator for your plants• Applying rates that are too low can lead to
nutrient deficiency and low yields. • Too high of nutrient rates can lead to nitrate
leaching, phosphorus runoff, accelerated eutrophication of lakes, and excessive vegetative growth of some crops.
Fertilizing Continued
• High Nitrogen Crops– Leafy veggies and corn
• High Phosphorus Crops– Pod and fruit crops
• High Potassium Crops– Root crops
Applying Fertilizers
• Broadcasting- spread amount of fertilizer equally over the entire garden and mix into soil before planting
• Sidedressing- Mix half into the soil before planting and apply the rest later in the season on top of the soil on each side of the rows about 3-4 inches from the stem.
Applying Fertilizers continued
• Banding- place the fertilizer in rows dug 3 inches from each side of the row of seeds or plants and slightly deeper than the depth planted.
• Plowing Under- if soil is very low in “P” and “K”, then add nutrients and plow under. Top dressing does not allow nutrients to be leached into soil fast enough.
Season Extension
• Interplanting method- plant a short term crop with a longer term plant so more crop can be grown in a smaller space. (i.e radishes and carrots, corn and pumpkins)
• Succession Planting- if using short term varieties, plant-harvest and replant another crop quickly to get maximum use of garden space.
Season Extension
• Crops can be planted at intervals of every two weeks so that they can be harvested throughout the season- less disease and insect pressure
• Replant areas where early crops, such as peas and lettuce are harvested with fall crops, such as kale or turnips. (succession)
• Use black plastic or mulch to cover ground to warm the soil and to keep weeds down.
Vegetable Crops: Increased Revenue and Cash Flow is our Goal
• Season Extension- early and late field plantings as well as mid season
• Increased early and late season market demand
Vegetable Crops: Increased Revenue and Cash Flow is our Goal
• High $ fall market especially last 2 years due to hurricanes in the south
• May have better size/quality, less disease/insect pressure in several plantings compared to continued harvest of main season plantings
Plasticulture Production Techniques
Season Extension- Zip House Performance
Floating Row Covers for freeze/frost protection
Staking and tying
• Prevent plant lodging under heavy fruit load
• Prevent plant lodging under wet soil conditions
• Prevents plant breakage under heavy fruit load
• Prevents wind damage to plant
• VERY LABOR INTENSIVE
Use of landscape fabric or weed matt
High Tunnels
High tunnel production
• Earlier harvest
• Higher fruit quality
• Dry plants= less disease
• Season extension
Sweet Corn Plastic Mulch Systems
• Potential benefits of clear plastic mulch
– Crop may mature 7-10 days earlier than unmulched
– May retain soil moisture (any mulch)
Crop Rotation
• Decreases insect/disease problems• Utilize nutrients already in soil provided by
previous crop• Example rotation
– Green, manure crops– High nitrogen crops, corn– Root crops– Solanaceous
• Back to beginning
Planting Methods
• Use fresh seeds from a reputable source
• Pay attention to last frost date in your area
• Plant according to directions on package
• Build “mini greenhouse” to protect seedlings from frost, increase germination rate/date, and increase temperature from sun so gardening can be started early in season.
Weed Control
• Don’t delay! Remove weeds when they are less than 1” tall and remove roots, too!
• Mulching/cover crops- straw, leaves, black polyethylene plastic, grass clippings, wood chips (nontreated) work well to control weeds and keep crops clean
Weeds• Annual weeds:
– Don’t delay! Cultivate before or soon after soil emergence roots and all!
– Smother with mulch (before or after weed seedling emergence);
– Flame weeding can work well but BE CAREFUL especially during the current drought.
• Mulching/cover crops- straw, leaves, black polyethylene plastic, grass clippings, wood chips (nontreated), newspapers, etc. work well to control weeds and keep crops clean
• In general: – Young weeds are easier to control by whatever
method.– Weeds can be composted, or used for mulch, if
they haven’t set seed.– If they have set seed, dispose of by burning,
burying, or similar solution.– Some weeds can harbor diseases.– Soil solarization can kill weeds and seeds at the
soil surface.
Soil Solarization with clear plastic:• Till soil, wet up real well;• Cover with heavy-duty clear plastic, anchored along
all edges;• Leave in the sun for several weeks to heat sterilize
upper inches.• Kills insects, eggs, seeds in the heated soil.• Poor control into deeper soil profile
Perennial Weeds
• Harder to control, as a rule
• Mulching can help
• Repeated cultivation and/or flaming can help
• Crop rotation, green manuring, etc. can help.
Don’t park the cultivator!!
Black Plastic Mulch• Warms soil earlier
• Suppresses weed growth
• Holds soil moisture
• Prevents soil splashing
• Cleaner fruit
• Can reduce disease
Raised beds, black plastic mulch & drip irrigation
Staking and Tying
• Florida Weave System
Staking Peppers
• Bell peppers should be staked to create a more upright canopy and reduce the risk of wind lodging
• Similar to tomatoes
Why use cover crops?• Add OM back to soil…• Reduce erosion…• Control weeds…• Conserve soil
moisture…• Control soil-borne
disease…• Increase fruit
cleanliness / quality at harvest…
Loss of SOM as CO2
Conventional agriculture is related to soil, air and water quality degradation
Acceleratednutrientsrelease(e.g. N)
Leaching, runoff andvolatilization of Nutrients with Conventional soil tillage
Chemical fertilizers dilemma
• Environmental crossroads
• Fossil fuelsAvailabilityCostPolitics
• N fertilizer production cost
Croprotation
Covercrops
No till
Cover Crops• Common types of cover crops
– Winter sown rye (annual)• Excellent biomass, sown in Fall
– Perennial rye grass• Good biomass, sown in Fall
– Hairy Vetch• Legume (+N), can be hard to kill
– Spring sown oats• Fall sown = very little biomass, spring sown = ok
biomass
• Not so common– Medics (annual legume from Australia)
• Fall seeded deteriorate over winter, spring seeded competes with crop
Benefits of cover crops
Common Mistake…Common Mistake…Seed is not placed in soilSeed is not placed in soilStrategy for success…Strategy for success…Plant to correct depthPlant to correct depthRoll before cover lodgesRoll before cover lodges
We have evaluated 32 different cover crops at OSU South Centers at Piketon for their suitability for:
-Biomass and nutrient management
-Biomass N contribution
-Nutrient recyclers
• Other characteristics
Cow peas
Alfalfa-timothy
Clover
Crimson clover
Austrian winter peas
Hairy vetch
Hairy Vetch- Fertilizer equivalent biomass N contribution ~ 80.6 + 4 lbs ac-1
Sudan-sorghum grass
Cereal rye
Sesame
Buckwheat-annual rye
Annual ryegrassFantasticStarfire
Cover cropsCpeas CClov HVetch LClov RClov Rgrass Rye Wpeas
Bio
mas
s (lb
s ac
-1)
0
5000
10000
15000
20000
25000
Fresh Dry
Cover cropsCpeas CClov HVetch LClov RClov Rgrass Rye Wpeas
N c
onte
nt (%
)
0
1
2
3
4
Cover cropsCpeas CClov HVetch LClov RClov Wpeas Rgrass Rye
N fe
rtili
zer
equi
v. (l
bs a
c-1
)
0
50
100
150
200
250
Total N fertilizer equivalent Biological N fixation
Soil
dept
h (in
)
Nitrate conc. (ppm)Hemphill and Hart (1993)
No cover crops Annual rye grass
Cover crops killing
5% vinegar @35 gallons ac-1
Roll over
Roundup
Challenges with cover crops:
Not a “Magic bullet”
Unable to replace chemical N fertilizers
Delay planting/poor germination
Initial lower crop yields (Transitional effect)
Challenges…..
Difficult to establish good stands
Compete with crops for nutrients
Immobilize soil N
Right combination (allelopathy)
Poor stand and persistence of hairy vetch as cover crops
Soil heaving effect onlarge seeded wintercover crops
Example: Austrian winter peas
Cons of using cover crops…
• Having field available in fall.• Extra costs and labor needed.• Chemicals will still need to
be used.• Cooler, wetter soils• Increased chance of
herbicide injury? • Longer production
schedules.• Vertebrate damage increases
Continue to look for appropriatecover crops for your farm
Vegetable Crop Disease Management
• Use IPM approach - multiple tactics• Manage water properly
– Trickle/drip irrigation better than overhead– Use raised beds
• Select best possible site– Open (good air movement), well-drained
• Improve soil quality– Organic amendments– Cover crops
• Practice appropriate rotations– Rotate away from similar crops at least three years
• Choose varieties with best resistance available– “Mountain” series: moderate resistance to early blight
(Mountain Pride, Supreme, Gold, Fresh and Belle) – Clean Seed
Disease Triangle
Disease Management
• Use IPM approach - multiple tactics• Select best possible site
– Open (good air movement), well-drained
• Improve soil quality– Organic amendments– Cover crops
• Practice appropriate rotations– i.e Tomatoes- Rotate away from solanaceous crops at
least three years
Pest Control/Prevention
• Dispose of crop residue (leftovers)
• Rotate Crops
• Use “treated” seeds
• Use “resistant” varieties
• Purchase healthy transplants
• Use limited chemicals if necessary– STAY SAFE…READ the DIRECTIONS!
In the Field - Cultural Tactics
• Mulches– Plastic or plant-based
• Reduce splash dispersal of pathogens• Protect fruit from soilborne pathogens
• Row orientation– Maximize air movement– Minimize leaf wetness periods
In the Field - Sanitation
• Destroy plant tissue post-season– Removes sources of inoculum
• Remove diseased plants and weeds in-season– esp. for late blight, bacterial diseases
• Sterilize plant stakes between crops• Clean tools, equipment frequently• Prohibit tobacco use
Watering and Irrigation
• Timeliness is important• Mother Nature does not always provide
moisture in a timely manner• Rule of Thumb= 1 inch of water per week• More or less required at different stages of
crop growth• Need to account for evapotransporation and
rainfall
Drip Irrigation
• Low volume requirements• Low pressure requirements• Put the water where the plant needs it the
most
Overhead Irrigation• Easy to manage
• Plant wettness
• Good for evaporative cooling of plants
• Large water volume required
• Large pressure and horsepower requirements
Direct seeding or transplanting?• Some plants don’t take transplanting well
(cucurbits, root crops, beans and peas).
• Some do (tomato, pepper, eggplant, greens of all types, early corn).
• Can gain 2 to 4 weeks by transplanting, depending on soil temperatures and crop.
• Cost, hassle trade-offs.
• May help get ahead of weed problems.
Use Clean Seed
• To control bacterial diseases
• Tomato seed are acid treated during processing/de-fuzzing– Not fully effective in sanitizing seed
• Other options– Clorox treatment (surface sanitation)– Hot water treatment (surface & internal)
Produce Clean Transplants
• Practice good sanitation in the greenhouse– Use new or sanitized
plug trays or flats and pathogen-free mixes
– Sanitize equipment– Install solid flooring;
raise seedling trays– Limit movement of
personnel and equipment between greenhouses
– Clean benches, greenhouse structure thoroughly after the crop
• Do not raise exotic or experimental vegetable varieties, or plants from saved seed, in the same greenhouse with commercial seedlings unless all seeds are treated
• Avoid raising or holding ornamental plants and vegetables in the same greenhouse
• Exclude insects (may carry viruses)
Produce Clean Transplants
• Maintain conditions in the greenhouse that do not favor disease development
– Maintain relative humidity as low as possible• Good air circulation• Proper temperatures
– Do not overwater
– Handle plants as little as possible
Produce Clean Transplants
Transplants
Larger cell size=earlier harvest
Vegetable Variety Selection
• The most important grower decision
• Grower experience is the best
• Variety evaluation is VERY TIME CONSUMING
• Consider all the factors
• Start with new varieties on a small trial scale first
Variety Selection• Use of “Adapted Varieties” or those have been proven to
grow well in this region– unadapted can lead to loss of 20% yield
• Study data from 3 years or more using regional variety trial results and your own on farm testing
• Agriculture Experiment Station field days and trials– summaries released yearly
• Private Seed Companies field days and trials• It takes 8-10 years for variety development, 2-3 more for
commercial production
On farm variety testing
Variety Adoption
• Market Acceptability: plant product must have characteristics desired by the buyer including size, shape, color, flavor, and nutritional quality
• Adaptability: Varieties must perform well under the range of environmental conditions usually encountered on the farm (drought, heat, cold, wet, wind)
Variety Adoption (cont.)
• Horticultural Quality: characteristics of the plant habit as related to climate and production practices of the plant product
• Concentrated set for machine harvest pickles, tomato, sweet corn, green bean.
Variety Adoption (cont.)
• Disease Resistance or tolerance: this is the most effective means of pest management (less costly than chemicals)
• Genetic resistance or tolerance to disease or insect• Virus masking in squash• When all other factors are equal it would be prudent to
select for resistance or tolerance
Variety Adoption (cont.)
• Yield
• The variety should have the potential to produce crops at least equivalent to those varieties already being grown
• Harvested yield may be much less than potential yield because of market constraints
Horticultural Quality Characteristics
• Quality traits of crop may be more important than yield characteristic
• “Super Sweet” sweet corn varieties
• Fruit size, color
• Spineless in squash
• Thornlessin blackberry
Want to Learn More? University trials and Field Days
Seed Company Field Days
Midwest Vegetable Variety Trial Report
•Reports from Illinois, Indiana, Iowa, Kentucky, Michigan, Missouri, North Dakota, and Ohio are included.
• Online:. http://www.hort.purdue.edu/fruitveg/reports.shtml
• To purchase:Purdue University Media Distribution Department. Tel: 1-888-398-4636.A new bulletin is published each year reflecting current season's trials from Midwestern states. Past issues are sometimes available.
Full reports of this and past years results:
• Brad BergefurdExtension Educator, HorticultureOSU South Centers1864 Shyville RoadPiketon, Ohio [email protected]://southcenters.osu.edu/hort/1-800-860-7232
• (614) 292-4900