Sydney Park Brown UF Consumer Horticulture Extension Specialist

Transcription

1 Sydney Park Brown UF Consumer Horticulture Extension Specialist

2 Today s Objective: To discuss organic gardening principles, techniques, products, and tips Healthy Soil Crop Selection and Management Nutrition Management Pest Management

3 Dr. Danielle Treadwell UF Hort Science Dept Organic and Sustainable Production Dr. Jeff Gillman U. of Minn. Hort Science Dept Nursery Management

4 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

5 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.

6 The spectrum: Too cheap/ Limit pesticides/ Purist too lazy build soil

7 Rely on: - Soil building through organic soil amendments - Wise crop selection and management - Natural products for fertility - Reduced reliance on pesticides

8 Part I. Healthy Soil

9 Curative Products Cultural Management Soil Management

10 Strategies: Increase organic matter Enhance physical properties Enhance soil biodiversity Prevent erosion

11 Soil is a matrix of minerals (sand, silt, clay), water and gases, organic matter and organisms.

12 OM - the single most important indicator of soil quality

13 Sources: Compost Plant residues (cover crops & green manures) Animal manures Commercial soil mixes

14 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

15 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.

16 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

17 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

18 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.

19 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

20 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

21 Human pathogens include: E. coli (can live in un-composted manure for 21 months!) Salmonella spp. Listeria Strepococcus spp. Clostridium spp. Giardia Cryptosporidium

22 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

23 Manure Source % Water % N % P % K Application Cow Mix 25 pounds Horse pounds rock phosphate per 100 square feet. Sidedress with up to 5 pounds per 100 feet. Sheep Mix 12 pounds per 100 Duck square feet. Sidedress Goose with up to 3 pounds per Hen feet. Turkey

24 Poultry litter: Contains zinc, copper and phosphorus Stall litter: Too high in carbon? Ties up nitrogen Grazing manure: Often contains weed seeds

25 Part II. Crop Selection and Management

26 Organic Strategies: Use untreated or organic seeds & transplants Crop selection Adapted to Florida Pest resistant Observe planting dates Crop rotation Florida Vegetable Gardening Guide

27 Organic Seed Source Databases: Seed retailers: Johnny s Selected Seeds Seeds of Change Peaceful Valley Farm Supply Southern States others

28 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

29 Alternate: Families Nutrient demands Short/long season

30 Rotation Groups Group 1 Cucurbit Family Group 2 Brassica Family Watermelon Cabbage Cucumber Group 3 Solanaceous Family Pepper (all types) Cauliflower Tomato Group 4 Beet Root Family Group 5 Pea and Bean Family Group 6 Onion Family Beets Beans Onions Swiss chard Squash Broccoli Eggplant Spinach English peas Snow peas Shallots Garlic Group 7 Other Sweet corn Sweetpotato Cantaloupe Brussels sprouts Irish potato Southern peas Leek Pumpkin Mustard Gourds Turnips Collards

31 Part III. Plant Nutrition

32 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

33 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

34 UF/IFAS Soil Testing Lab

35 Formulated, balanced fertilizers 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

36 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 Mg Mn P

37 Soil microorganisms transform organic nutrients into forms plants can use W.J. Hickey, Univ. Wisconsin Nitrobacter winogradskyi uses nitrite to grow and produces nitrate.

38 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

39 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

40 25 lb bag = $28 33 lb bag = $15

41 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 Day Rule.

42 Part IV: Pest Management (Weeds, Insects, Diseases)

43 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

44 Refer to the National List Look for OMRI label Look for NOP/EPA label Contact your county extension office

45 Prevention Strategies: Limit weed seed production Limit weed seed dispersal Limit weed seed introduction One Pigweed Plant 13,000-35,000 seeds

46 It s all about Managing the weed seed bank One year-old FL Pusley seeding = 7 years of weeding!

47 Cultural Strategies: Don t water/fertilize weeds Flaming Hand pulling Shallow cultivation Mulch Use Cover crops Solarize soil in summer The Hula-Hoe

48 Herbicide Strategies Burn off products (garlic oil, clove oil, vinegar, pelargonic acid) Corn Gluten Meal (pre-emergence)

49 Prevention Strategies: Turn soil well in advance of planting (30 days) Purchase pest-free transplants Intercrop confuses insects Row covers Traps/Lures

50 Cucumber Beetle Eggs 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

51 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

52 Prevention Strategies: Sanitation Crop rotation Resistant cultivars Ample air circulation Solarization in summer

53 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)

54 Cultural Strategies: Keep plants vigorous Keep plant foliage dry Intercrop Remove infected foliage/fruit Remove finished crops Tomato bacterial spot (Xanthomonas) (R)

55 Down Time - Crop free time periods Downy Mildew on Basil Spores of DM on Basil Downy Mildew - Must have a live plant to survive. Remove infected plants.

56 Fungicide Strategies: Spray fungicides preventatively or soon after infection Good choices: Bacillus subtilis (Serenade or Rhapsody) Copper compounds Sulfur Baking Soda

57 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.

58 Questions? Comments?

59

60 K is supplied from breakdown of soil minerals and clays Sul-po-mag (potassium magnesium sulfate 18% Mg, 22% S) Potassium sulfate (0-0-22) Gluconate or greensand (0-0-7)

61 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.