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Sydney Park Brown UF Consumer Horticulture
Extension Specialist
Today’s Objective: To discuss organic gardening principles, techniques, products, and tips Healthy Soil Crop Selection and Management Nutrition Management Pest Management
Dr. Danielle Treadwell UF Hort Science Dept Organic and Sustainable Production
Dr. Jeff Gillman
U. of Minn. Hort Science Dept Nursery Management
…let’s distinguish organic gardening from organic farming
Organic farming falls under USDA - NOP NOP - created in the 1990 Farm
Bill; implemented in 2002 NOP established certifications
Organic farms are certified. Agricultural products derived from
those systems can bear the USDA (NOP) organic label.
Agricultural inputs are not “certified
organic.” They are “approved for use in organic production.”
Gardeners, by definition, are not required to be certified.
The spectrum: Too cheap/ Limit pesticides/ Purist
too lazy build soil
Rely on: - Soil building through
organic soil amendments
- Wise crop selection and management
- Natural products for fertility
- Reduced reliance on pesticides
Part I. Healthy Soil
Soil Management
Cultural Management
Curative Products
Strategies: Increase organic matter Enhance physical properties Enhance soil biodiversity Prevent erosion
Soil is a matrix of minerals (sand, silt, clay), water and gases, organic matter and organisms.
OM - the single most important indicator of soil quality
Sources: Compost Plant residues (cover crops & green
manures) Animal manures Commercial soil mixes
Compost: once-living things Requires prolonged microbial decomposition Microbes need oxygen, moisture and “food” Carbon:Nitrogen ratio - 25:1 to 40:1 for rapid
composting Temperature must reach 131º – 170º F to kill
weed seeds and pathogens
“Compost Tips for the Home Gardener” http://edis.ifas.ufl.edu/ep323
Compost Add 1-3 inches of compost to the soil surface
(25 lbs/ 100 sq feet or ¼ lb/ sq foot). Mix to a depth of 4-6 inches. Apply two to three weeks before planting. Only a small quantity? Mix into the soil along
each planting furrow or at each hill site.
Green Manure Crop – plants are grown on garden site and turned into the soil Cover Crop – grown when usual crop is absent;
may not be returned to the soil
So…all green manures are cover crops; not all cover crops are considered green manure.
Rye Cover Crop/Green Manure in Home Garden
Benefits: Prevent erosion Increase OM in soil Provide food for soil microbes Some are “nematicidal” cowpea, sunn hemp, marigold, sorghum,
velvet bean, rye, bahia
“Soil OM, Green Manures, and Cover Crops for Nematode Management” http://edis.ifas.ufl.edu/vh037
Between seasons: Buckwheat
Winter: Cereal rye (‘FL 401’), crimson clover*, Austrian
winter pea* Summer: Cowpea*, velvet bean*, soybean*, sunflower
(short varieties), pearl millet (NOT proso millet) * Legumes that fix atmospheric nitrogen and return it
to the soil. Incorporate < 2 weeks before crop.
Managing the cover crop/green manure Choose a rapidly growing CC/GM Plants should take time to develop seeds Cut at maximum succulence and growth Don’t allow set seed
Crimson Clover
Similar to compost (once-living things) Offers more nutrients than compost Raw (fresh) manure:
contains ammonia which can burn can contain human pathogens compost before using
Human pathogens include: E. coli (can live in un-composted manure
for 21 months!) Salmonella spp. Listeria Strepococcus spp. Clostridium spp. Giardia Cryptosporidium
Raw Manure - NOP 90/120 Day Rule*
If manure does not touch edible portion, apply 90 days in advance of harvest If manure does touch, apply 120 days
ahead of harvest
*National Organic Production
Manure Source
% Water
% N % P % K Application
Cow 86 0.55 0.15 0.50 Mix 25 pounds + 2-3 pounds rock phosphate per 100 square feet. Sidedress with up to 5 pounds per 100 feet.
Horse 80 0.65 0.25 0.50
Sheep 68 1.0 0.75 0.40 Mix 12 pounds per 100 square feet . Sidedress with up to 3 pounds per 100 feet.
Duck 61 1.10 1.45 0.50 Goose 67 1.10 0.55 0.50 Hen 73 1.10 0.90 0.50 Turkey 74 1.30 0.70 0.50
Poultry litter: Contains zinc, copper and phosphorus
Stall litter: Too high in carbon? Ties up nitrogen
Grazing manure: Often contains weed seeds
Part II. Crop Selection and
Management
Organic Strategies: Use untreated or organic
seeds & transplants Crop selection Adapted to Florida Pest resistant Observe planting dates
Crop rotation
Florida Vegetable Gardening Guide http://edis.ifas.ufl.edu/vh021
Organic Seed Source Databases: http://seeds.omri.org http://attra.ncat.org/attra-
pub/altseed_search.php
Seed retailers: Johnny’s Selected Seeds Seeds of Change Peaceful Valley Farm Supply Southern States others
Growing Organic Transplants: Sanitation: Bleach Avoid synthetic wetting agents or starter
fertilizer Soil Recipe: Mix 1 part each of peat, perlite, compost Add 1.5 c blood meal, bone meal,
greensand, and superfine dolomitic lime
Alternate: Families Nutrient demands Short/long season
Group 1 Cucurbit Family
Group 2 Brassica Family
Group 3 Solana-ceous Family
Group 4 Beet Root Family
Group 5 Pea and Bean Family
Group 6 Onion Family
Group 7 Other
Watermelon Cabbage Pepper (all types) Beets Beans Onions Sweet
corn
Cucumber Cauliflower Tomato Swiss chard
English peas Shallots Sweet-
potato
Squash Broccoli Eggplant Spinach Snow peas Garlic
Cantaloupe Brussels sprouts Irish potato Southern
peas Leek
Pumpkin Mustard
Gourds Turnips
Collards
Rotation Groups
Part III. Plant Nutrition
Organic Strategies: Provide sufficient nutrition Adjust pH (2-3 months ahead of planting) Use natural fertilizers Combine fast- and slow-release fertilizers Prevent run-off
Test soil pH after OM is applied Sulfur and lime considered organic
amendments Reapply after one or two years Synthetic amendments: iron sulfate,
aluminum sulfate, magnesium sulfate approved for organic production by USDA
UF/IFAS Soil Testing Lab http://soilslab.ifas.ufl.edu/ESTL
Dry and liquid formulations Plant and animal meals (alfalfa,
soybean, bone, feather, fish and blood meal) Fish emulsion Kelp (seaweed extracts) Dehydrated and pelletized manures Compost Formulated, balanced fertilizers
Reuse nutrients from other living sources Offer a wide range of nutrients (micros too) Offer nutrients at a low concentration Are less likely to burn roots Deliver nutrients slowly over
a long time N
Fe
K
P
Mg
Mn
Soil microorganisms transform organic nutrients into forms plants can use
Nitrobacter winogradskyi uses nitrite to grow and produces nitrate.
W.J. Hickey, Univ. Wisconsin
SLOW (controlled release): depends on temperature, moisture and microorganisms. Urea & polymer coated fertilizers (synthetic) Feather meal Compost - 25 lbs/100 sq ft = .0375 lbs N per
100 sq ft * Un-composted plant material (leaves,
mulch) Green manures and cover crops
FAST (soluble; nutrients release <1-4 wks): Water-soluble fertilizer (synthetic) Blood meal Soybean meal Fish emulsion Kelp Succulent legumes soil incorporated
< 2 weeks before crop
25 lb bag = $28 33 lb bag = $15
A water extraction of microbes and nutrients.
Does not consistently suppress disease pathogens.
Does not provide a measureable amount of nutrition to plants.
Raw manure tea prohibited - does not follow the “90-120 Day Rule.”
Part IV: Pest Management
(Weeds, Insects, Diseases)
Organic Strategies: 3-step approach 1. Prevention Sanitation, exclusion, crop rotation, resistant
cultivars 2. Cultural Practices Observe planting dates, introduce/nurture
beneficials, use mulch, trouble-shoot frequently (1-2x/wk)
3. Pesticides Use only as a last resort
Refer to the “National List” Look for OMRI label Look for NOP/EPA label Contact your county extension office
Prevention Strategies: Limit weed seed production Limit weed seed dispersal Limit weed seed introduction
One Pigweed Plant 13,000-35,000 seeds
It’s all about… Managing the weed “seed bank”
One year-old FL Pusley seeding = 7 years of weeding!
Cultural Strategies: Don’t water/fertilize weeds Flaming Hand pulling Shallow cultivation Mulch Use Cover crops Solarize soil in summer
The “Hula-Hoe”
Herbicide Strategies Burn –off products (garlic oil, clove oil,
vinegar, pelargonic acid) Corn Gluten Meal
(pre-emergence)
Prevention Strategies: Turn soil well in advance
of planting (30 days) Purchase pest-free
transplants Intercrop – confuses
insects Row covers Traps/Lures
Cultural Strategies Keep plants vigorously
growing Scout often for first signs of
pests Hand pick pests Harvest frequently Create refugia/nectaries Avoid broad-spectrum
pesticides (synthetic or natural) that kill beneficials
Cucumber Beetle Eggs
Insecticide Strategies:
Organic does not mean completely safe (Ex: nicotine, rotenone, pyrethrum)
Good choices: Bt – Bacillus thuringiensis Beauvaria bassiana Repellents – Capsaicin, Garlic Neem Oils Soaps Spinosad
Prevention Strategies: Sanitation Crop rotation Resistant cultivars Ample air circulation Solarization in summer
Crop Resistance
…the cheapest, easiest, safest, and most effective way to manage disease … especially important
for soil-borne diseases e.g. verticillium wilt (V), fusarium wilt (F) and nematodes (N)
Cultural Strategies: Keep plants vigorous Keep plant foliage dry Intercrop Remove infected foliage/fruit Remove finished crops
Tomato bacterial spot (Xanthomonas) (R)
“Down Time” - Crop free time periods
Downy Mildew on Basil
Downy Mildew - Must have a live plant to survive. Remove infected plants.
Spores of DM on Basil
Fungicide Strategies: Spray fungicides preventatively
or soon after infection Good choices: Bacillus subtilis (Serenade or
Rhapsody) Copper compounds Sulfur Baking Soda
Organic gardening is more than just substituting synthetic inputs for natural ones.
Commercial organic products are expensive. Natural organic products are cheap, but can
be labor intensive. An organic garden takes time to develop.
Disclaimer: Mention of certain products should not be construed as an endorsement of that name brand.
Questions? Comments?
K is supplied from breakdown of soil minerals and clays
Sul-po-mag (potassium magnesium sulfate – 18% Mg, 22% S)
Potassium sulfate
Gluconate or greensand (0-0-7)
(0-0-22)
Synthetic P is not allowed Rock and colloidal
phosphate have low availability and are not practical amendments.
Fish meal, bat guano and poultry litter are high in P.