Comprehensive Guide to Soil Nutrition for Vegetable Gardening

1. Introduction to Vegetable Gardening • What is a Vegetable? • What is a Fruit?

2. What is a Vegetable? • A vegetable is, typically, an herbaceous plant used for the main part of a meal • A vegetable is defined by use of the plant part and not some common botanical characteristic

3. What is a fruit? • A botanical definition for fruit is themature ovary of the plant, consisting of the seeds and their coating • A more general definition for fruit is the reproductive part of a plant; the seed of plants or the part that contains the seed

4. A quick review of soils and nutrition • Plants get the majority of the elements (nutrients) from the soil • Two stages to improving the soil in your garden • Create or rebuild a fertile and friable soil • Maintain fertility despite the drain of year-in, year out losses from leaching, erosion and vegetable harvest

5. Nutrients needed by plants

6. Nutrients needed by plants • The way to determine if the soil contains adequate levels of nutrients is through a soil test • Make sure that your sample(s) for the soil test are representative of the garden • You can send the sample to a commercial laboratory or you can purchase and use a home soil testing kit

7. Major plant nutrients • Nitrogen (N) • The nutrient most likely to be deficient • Most soil nitrogen is contained in the organic matter • Is the essential building block of proteins and chlorophyll • Generally is in the nitrate or ammonium form or in organic matter in the soil

8. Nitrogen • Nitrate • Form used by the plants • Leaching losses • Denitrification- in waterlogged soils, N can be converted by microbes into atmospheric nitrogen • Nitrogen deficiency • Symptoms: Yellowing of the leaves, especially the older leaves • Treatment: apply a material high in nitrogen • Legumes, manures, animal byproducts, synthetic fertilizers

9. Nitrogen (N) • Excess nitrogen • Easy to over apply nitrogen • Will cause: • Delayed maturity • Uneven ripening • Overly succulent growth – can lead to pest problems

10. Phosphorus (P) • Generally considered to be in the form of phosphate (P2O5) • Most soils contain large amounts of P but not in forms available to the plant • Functions • It is important for the distribution and storage of energy in forms of sugars and starches • Is important for root growth • Stimulates flower, fruit, and seed development

11. Phosphorus (P) • Phosphorous deficiency • Symptoms: Slight stunting of the plant, older leaves will be purplish, and undeveloped root system • Treatment: • Apply bone meal • Apply a synthetic fertilizer containing a high level of phosphorous • Phosphorous does not move very much in the soil

12. Potassium or Potash (K) • Where did the name potash originate? • Considered to be in the form of K2O • Not leached readily • Is essential for synthesis of proteins and carbohydrates • Is needed in higher amounts by root crops • Organic fertilizers are often low in potassium

13. Potassium • Potassium deficiency • Symptoms: • Small inferior flowers and fruits and stunted plants. • Yellowing along the edges of older leaves • Leaves become bronzed • Treatment is to apply a fertilizer high in K

14. Calcium • Calcium • Plays an important role in cell wall development • Calcium deficiency problems: • Sometimes calcium is present, but plants cannot adequately distribute it (uneven irrigation practices…)

15. Calcium • Symptoms • Tipburn in lettuce and cabbage • Blossom-end rot in tomatoes • Treatment • There is no immediate “cure” for calcium deficiency problems • Adding materials high in calcium will not solve the problem • Maintain even watering • Mulch the plants • Maintains more even soil moisture

16. Secondary Nutrients • Magnesium • Magnesium deficiency • Symptoms: yellowing starting between the veins of the older leaves • Sulfur • Generally not a problem • Used for making soils more acidic and is found in compost and manures

17. Micronutrients • Are needed in very small quantities • Generally all micronutrients are available in organic materials you apply to the garden • Best treatment is to prevent the problem from occurring in the first place • Availability is determined by soil pH

18. Soil pH: Acidity and Alkalinity • What is pH? • pH is –log[H+] • pH is a scale from 1 to 14 • Why is pH important? • Because nutrients are more or less available depending on the soil’s pH • The ideal range is 6.2 to 6.8

19. Soil pH • Influences disease problems • Acid soils promote club root disease of cabbage • Adjusting the pH • Lime is used to raise the pH • Sulfur is used to lower the pH

20. Soil amendments/ Fertilizers • Animal manures • Are intermediate between a soil amendment and a fertilizer • Vary greatly in their nutrient composition • Caused by: • Animal • Feed used • Type of litter or bedding • Degree of composting or decomposition • Must be composted before use with minor exceptions

21. Animal Manures • Problems with manures • May contain harmful or undesirable contaminants • E coli and other harmful bacteria may be in fresh manure • Manures are low in nutrients compared to synthetic fertilizers • The most common commercially available types of manures • Cow manure • Chicken (Poultry) manure • Bat guano • Seabird guano

22. Animal Manures

23. Table: Typical Composition of Manures

24. Starting your vegetable garden Seeds vs transplants

25. Starting Plants from Seeds • Introduction • Definition:A seed is a dormant, undeveloped plant • A seed contains all the genetic material necessary for the development of a mature plant • Basic parts • Seed coat • Embryo • Food supply in either endosperm or cotyledons

26. Factors Determining Seed Quality • Disease-free seed • You do not want to use contaminated seed because it may be very difficult to eliminate the disease from your garden • Generally seedborne diseases are a problem when gardeners collect their own seed • Ways diseases can be carried • On the seed coat • Seed treatments can eliminate • Within the seed • Hot water treatments can eliminate

27. Factors Determining Seed Quality • Disease-free seed • Some commercial seed companies treat their seeds with fungicides • Fungicide treated seed is not acceptable in organic gardening • Seed packet should contain warning if seed is Treated • If seed is pink or has powdery substance on it then it was treated with a fungicide • Wear gloves when handling

28. Factors Determining Seed Quality • Viability • Definition:viability is the percentage of vegetable seed which will germinate • Viability refers to is the seed living or respiring • Vegetable seed viability is tested by seed companies and on seed packets the germination percentage and test date are listed • Factors affecting viability • Vegetables naturally differ in their viability • Age of the seed will affect viability

29. The Viability and Longevity ofVegetable Seed

30. Factors Determining Seed Quality • Seed Purity • Definition:seed purity means that the seed is true-to-type and does not contain undesirable contaminants • The seed are what the package says it is • Contaminants that may occur in seed packets • Seed of the wrong cultivar • Seed of the wrong vegetable species • Weed seed • Soil particles or plant parts

31. Factors Determining Seed Quality • Seed purity and noxious weeds • Definition: noxious weeds are plants that federal, state, or local governments want to prevent from spreading to and establishing in a particular area • These seed are prohibited from being contaminants in seed that are commercially sold • Examples • Field bindweed • Canada thistle

32. Factors Determining Seed Quality • Seed purity and collecting your own seeds • It is important to maintain the cultivar genetically pure when collecting your own seed • Maintaining genetically pure seeds only works for self-pollinated cultivars that are open pollinated • You can not maintain pure seed when: • The parents are hybrids • Wind pollinated vegetables • They can be pollinated by related plants from a distance away • Insect pollinated vegetables readily cross pollinate, if required distances are not kept

33. Factors to consider whenplanting seed • Germination requirements • Soil temperature • Soil moisture • Light / dark • Planting depth

34. Germination requirements • Soil temperature • Plant processes including seed germination and vegetative growth are temperature dependent • Soil temperature and moisture are closely interrelated • Wet soils are cooler than dry soils • In cold soils seedlings emerge slowly and are prone to attack by soilborne pathogens

35. Germination requirements cont. • Each vegetable crop has: • An optimum temperature for germination • Temperatures below or above which germination will not occur • The response of most biological processes such as germination to temperature is a sigmoidal (bell-shaped) curve

36. Germination Requirements • Soil Moisture • Soil moisture ranges from the permanent wilting point (lowest moisture) to field capacity (highest moisture) • Field capacity: the maximum amount of water that your particular soil will hold • Permanent wilting point: point where a plant can no longer remove the small amount of water remaining in the soil and the plant wilts • Plants varying in their ability to germinate at different soil moistures • Low moisture: cabbage, pumpkin • High moisture: beets, lettuce

37. Planting Depth • Planting depth • Seed has a limited amount of food reserves and can exhaust those before it reaches the surface, if planted to deep • Rule of thumb: vegetable seeds should generally be planted to a depth equal to twice the diameter of the seed

38. Planting Depth • Factors influencing depth of planting • Weather conditions • Wet weather plant seed shallower • Type of soil • Heavy soils plant seed shallower • Soil crusts • Some of our soils tend to form crusts • Plant shallower or apply vermiculite or peat moss over the seed

39. Starting Plants from Transplants • Definition– transplanting is the shifting of plants from one soil or growing medium to another • Goal is to produce vigorous plants ready to be planted in the garden

40. Why use transplants? • Improves the earliness of the vegetables • Avoids problems of seed emerging through soil crusts or in cold soils • You can more closely control depth of planting • Make best use of expensive or unavailable seeds • Seed germinates under ideal conditions

41. Not all vegetables transplant well • Plants difficult or not to transplant include: • Root crops (carrots) • Leafy biennial herbs (dill and fennel) • Heading types of Chinese cabbage • Cucurbits (cucumbers, pumpkins, squash) • Do not like their root systems disturbed • Vegetables growing quickly when seeded in the garden (lettuce, spinach) • Transplanting is not worth the effort

42. Vegetables TraditionallyTransplanted • Small seeded vegetables • Tomatoes, peppers, cabbage, broccoli • Some vegetables are traditionally started from transplants because they do not produce seed or the seed lacks uniformity • Sweet potato, Irish potato

43. Commercially Available Transplants • To select quality transplants look for: • Healthy plants • Free of insects or diseases • Vigorously growing • Avoid transplants that already have flowers or small fruit – a sign of stress, or are spindly • "True to type“ • All the plants are actually the vegetable and “variety” / cultivar that the label indicates • Properly handled

44. Commercially Available Transplants • To select quality transplants look for: • Transplants that are not leggy or spindly • A source that regularly deals with transplants • Purchase transplants early in the season before they are picked over

45. Producing your own transplants • Key factor in determining success – • Having an adequate amount of protected growing space to produce transplants • May need: • Specialized structure • Supplemental lights

46. Producing your own transplants • Growing Media • Want to use a soil-less growing media that does contain soil from your garden or yard • Why not use garden soil? • Tends to be poorly drained and subject to water logging • Contains insect pests, diseases, and weed seed or mostly big rocks • Serpentine soil

47. Producing your own transplants • Light • Is the environmental factor that is most likely to be limiting for growing your own good quality transplants • Interrelated with temperature and moisture • Inadequate light often leads to cold temperatures and too much moisture • Too little light causes weak spindly plants susceptible to diseases • Vegetable transplants need more light than standard houseplants

48. Producing your own transplants • Light • Components of light • Intensity • Wavelength • Plants require different wavelengths than our eyes perceive • Day length • Plants use day length to tell when summer or winter is coming • Inadequate levels of any of these components will cause a plant to sense inadequate level of light

49. Producing your own transplants • Temperature • In windows there can often be large temperature fluctuations between day and night or sunny and cloudy days • Cooler than optimum temperatures may: • Encourage disease • Cause rough fruit in tomatoes • Cause bolting in biennials • Warmer than optimum temperature may cause weak spindly seedlings

50. Producing your own transplants • Moisture • Too much moisture is often associated with cool temperatures and dark conditions • Too much water is associated with diseases which require moisture for spread • Examples: root rots, leaf spot • Ways to avoid problems with diseases fostered by too much water • Thoroughly water when seeding • After seeding water in the morning so leaves will be dry before night and spot water only the dry places • Too little water rapidly kills young seedlings