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.