VEGETABLES
KEY CONCEPTS I. Site II. Planning III. Cultural Practices Starting seeds indoors Planting seeds and transplants outdoors Timing Planting depth Fertilizing Amount of fertilizer Timing of fertilizer application Methods of applying fertilizer Organic and synthetic fertilizers Watering Amount of water When to water Methods of watering Sanitation Weed control Cultivation Mulching Herbicides Harvesting Fall cleanup Crop rotation Insect control Animal control Disease control Preventive practices Fungicides   Return to Introduction		CULTURAL PRACTICE Following the best cultural practices helps prevent disease and promote optimal harvest.   STARTING SEEDS INDOORS Some vegetables are placed in the garden as transplants. Transplants may be purchased or grown from seed as outlined in the chapter on plant propagation. Onion and leek plants are infrequently found in garden centers. Growing your own transplants increases the cultivar selection of other crops. A group of vegetables that easily transplants and is suitable for starting indoors includes broccoli, cabbage, cauliflower, celeriac, eggplant, lettuce, sweet potato slips, onion, leek, tomato and pepper. The following group requires some care with transplanting: beet, celery, chard, melon and squash. Beans, corn, cucumbers, peas and okra should be direct-seeded when soil conditions and temperature are right. Timing of seed-starting indoors and outdoors is critical to the success of the vegetable garden. Check a garden calendar for the recommended time to plant transplants outdoors. Then, start seeds for that crop indoors the appropriate number of weeks earlier. Keep records so you can modify the seed-starting time in the future, if necessary. The exact time to start seedlings will vary a little based on conditions in the home, the light source and the cultivars grown.   PLANTING SEEDS AND TRANSPLANTS OUTDOORS Planting seeds and transplants at the right time of the season is a key to enjoying a large, quality harvest. Before planting seeds, be sure the soil is thoroughly worked and free of clumps. This will ensure the necessary contact between seeds and soil. Stake off rows according to your plan and be sure to identify the crop planted with markers. Plant at the proper depth and spacing so excess thinning will not be necessary. Save some seed for planting later in case unforeseen conditions result in poor germination. Harden off all transplants before planting. While the plants are indoors, gradually reduce the amount of water and fertilizer applied. Gradually increase the exposure of young plants to the outdoors by moving seedlings to an area like a shaded porch. Move the plants back indoors at night if temperatures go below 50 degrees F. Cool-season crops can tolerate cooler temperatures once they've been hardened off. But, they should not be exposed to near freezing temperatures as seedlings. This can cause some plants to BUTTON (form small heads of broccoli or cabbage) or bolt (form flowers instead of vegetative growth). Gradually increase the length of time the plants are in sunny or windy areas until they spend all day and night outside. This acclimation process takes about 10 days. When buying vegetable transplants, look for stocky, full plants. The roots should fill the pot, but they should not be pot-bound. Roots should be white or tan, not brown. Do not purchase transplants that are diseased or infested with insects. Transplant seedlings to the garden on a cloudy day, or late afternoon/early evening, if possible. Remove flowers and small fruits from transplants to ensure more vegetative growth before fruit production begins. Young plants that are allowed to produce fruit may not develop properly because the plant's energy is directed to fruit production instead of root and stem development. Transplants that have already started to fruit are under stress due to roots being confined too long.   TIMING Seeds and transplants have temperature and moisture ranges within which they will grow. Planting too early in cold, moist soil may result in rotted seeds or stunted transplants. Cool-season plants will not produce quality crops if planted too late. The conditions must be right for the start of growth in the garden. There also must be an adequate number of seasonable days for the plants to mature before harvest. Carefully kept records will help you refine these dates for your growing conditions.   PLANTING DEPTH For spring planting of seeds indoors and outdoors, follow directions on the seed packet. A general rule is to plant the seed twice as deep as the diameter of the seed. This means that most large bean or squash seeds are planted about 1 inch deep. However, if the package recommends the seeds not be covered with soil, just sprinkle them on the surface of the soil and lightly tamp them for good soil contact. Plant transplants in the garden at the same level as they were growing in the container. Tomato and broccoli plants are exceptions to this rule. Tomatoes will form roots all along their stems if covered with soil. If tomato seedlings are spindly, plant them in trenches so only a few top inches of the plant are above soil level. It's best to place the stakes before planting in this manner; some gardeners have driven stakes through buried stems! Broccoli also will form some roots along its stem when covered with soil.   FERTILIZING   Fertilizing should be done according to the results of a soil test. Although soil tests can be done at any time of the year, a soil sample tested in the fall will allow plenty of time for lime to react with the soil, if it is a needed amendment, before spring planting. An annual fertilization program or maintenance fertilization program is necessary to keep soil nutrients at desired levels. Research shows that at the end of the growing season, average garden soil has lost 1 to 3 pounds of nitrogen, 1/2 to 1-1/2 pounds of phosphorous, and 2 to 4 pounds of potassium, per 100 square feet of garden soil. A recommendation for maintaining soil fertility is to add 2 to 4 inches of organic matter per year and maintain the proper pH by adding lime based on test results. Add fertilizer according to the test results. Healthy soil is maintained by adding quality organic matter. Leaf humus, compost and composted manures provide nutrients and promote desirable soil pH for nutrient availability and uptake by roots. Organic matter adds small amounts of nutrients and decreases leaching of nutrients from the soil. It also provides food for soil animals and microorganisms that decompose coarse, organic materials. This adds life to the soil.   AMOUNT OF FERTILIZER There are some general factors that determine both the composition and amount of fertilizer to add. Not all vegetables require the same type and amount of nutrients. When a soil test is not available, the following general recommendations usually are given. Use 1 to 2 pounds of a balanced fertilizer for every 100 feet of row. If applied to an unplanted area, sprinkle 2 pounds of fertilizer for every 100 square feet of garden. To eliminate guesswork, remember that 2 cups of fertilizer is approximately 1 pound by weight. Leafy vegetables (collard, kale, lettuce, mustard, Swiss chard, etc.) benefit from 10-10-10 or 12-12-12 fertilizer formulations. Other vegetables grown for fruit, roots or bulbs benefit from 5-10-10 or 5-10-5 formulations. Remember that nitrogen produces healthy, dark green leaves, phosphorous produces strong roots and seeds, and potassium contributes to overall plant health. Of these three nutrients, nitrogen is the only one that must be added each year. The other two do not leach from the soil since they are bound to clay and organic particles. Based on soil test results, a gardener may only need to apply a little nitrate of soda (synthetic source) or bloodmeal (organic source) to provide adequate nutrients for the garden. Gardeners who employ the intensive techniques will need to add a little extra fertilizer after the removal of a particularly heavy feeding crop. Many gardeners make the mistake of overfertilizing. This practice can lead to nutrient deficiencies because of nutrients binding to the excess elements. Restoring nutrient balance after applying too much fertilizer is nearly impossible in the short run.   TIMING OF FERTILIZER APPLICATION There are various times when fertilizer is best applied. Fertilize seedlings grown indoors after the first true leaves appear. Use liquid fertilizers mixed at half the label's recommended strength. For non-fruiting crops, use 20-20-20. Select 15-20-15 for fruiting crops. Transplants benefit from the application of a starter fertilizer at planting. Make the starter fertilizer by mixing 2 tablespoons of 5-10-5 or 5-10-10 in a gallon of water. The filler in the fertilizer will not dissolve and can be added to the soil after applying the solution. Water the transplant thoroughly and then add about 2 to 4 cups of starter fertilizer. Fertilizer can be broadcast onto the soil before planting. This method, when followed by turning the soil, gets the nutrients to where the roots can absorb them. Fertilizer can be applied around plants growing in the garden. This is called side-dressing. Here, the idea is to add a little nitrogen. Nitrogen may become limiting during the summer. Make applications to leafy crops after they are well established. Fertilize sweet corn when it's 12 to 15 inches high. Fruiting crops, such as tomatoes and cucumbers, should be sidedressed after the first fruit is set. Be careful when applying fertilizer during hot weather when soil moisture is limited. Water tends to move toward the fertilizer (a salt) and away from the roots. The roots desiccate or "burn." Apply fertilizer just before a rain or irrigating the garden. Never allow granular fertilizer to remain in contact with foliage; it will "burn" the foliage.   METHODS OF APPLYING FERTILIZER Row or band fertilizing is a common and economical method of application. Narrow bands of granular fertilizer is sprinkled 3 inches to each side all along the plant row. Work the fertilizer into the top 2 to 3 inches of soil. Be careful not to damage plant roots by applying too close to roots or when working fertilizer into soil. Apply fertilizer at the rate recommended by a soil test. An alternative method is to broadcast the fertilizer by sprinkling it lightly over the entire garden soil before planting. Fertilizer can be lost by leaching or taken up by weeds if the gardener delays planting the garden. Fertilizers are also available in water-soluble form and are promoted to "feed" by applying to the foliage. This is generally regarded as an expensive way to fertilize the garden. Remember that the leaves do not absorb much water; it's the function of the roots to absorb. These liquid fertilizers often have a high percentage of nitrogen that can delay fruit production in sensitive crops like peppers. However, they can be used as a ready source of nitrogen for a plant that is showing a nitrogen deficiency.   ORGANIC AND SYNTHETIC FERTILIZERS Experienced gardeners use both organic and synthetic fertilizers to take advantage of the best qualities of each product. Generally, this is done by using the synthetics in early spring as starter fertilizers and organics during the warmer summer months. Common synthetic fertilizers include 5-10-10, 10-10-10, superphosphate and nitrate of soda. Common organic fertilizers include bloodmeal, bonemeal, GREENSAND, fish emulsion and COMPOSTED MANURES.   WATERING Water is necessary for all stages of vegetable growth from seed germination through flowering, fruit maturation and seed development. It is essential for crops to reach their full production potential. Watering or irrigation is often abused by the gardeners through overwatering, underwatering or watering at the wrong time.   AMOUNT OF WATER Vegetables generally require 1 inch of water per week for normal growth. When rainfall does not supply this amount, supplemental water is necessary. Local weather forecasts and weather data reported in the newspaper give a generalized picture of rainfall levels for an area. Soil moisture will vary with temperature, wind conditions and soil type. A rain gauge provides accurate data for your garden.   WHEN TO WATER It is best to water vegetable crops in the morning. Plants need moisture most during the day while they are photosynthesizing. It is important that plants go into the night with their leaves dry because moisture on leaves promotes fungal disease. If evening is the only possible time to water, avoid splashing water on the foliage by directing the flow onto the soil. It is also best to provide the supplemental water all at one time, thoroughly soaking the soil. Avoid frequent, light sprinklings. These result in shallow root growth that makes crops more susceptible to drought stress. Frequent evening sprinklings increase the potential for foliar diseases. Stages of crop development that are critical in terms of moisture requirements are seed germination and transplant establishment. Furthermore, different vegetables require water at specific times during their development for best quality. Root crops need a constant supply of water during root development. Fruit crops, like tomatoes and peppers, should not be allowed to wilt between flowering and fruit production. Adequate water during the tasseling stage results in best ear development in corn.   METHODS OF WATERING Water vegetables deeply by soaking soil to a depth of 5 to 6 inches. Apply water at a rate of about 1/2 inch per hour to prevent runoff. If the rate of application of a watering system is unknown, use the tests in the lawn chapter to determine how much water is delivered. The ideal watering system delivers the water to the soil without getting the foliage wet. Emitter-type systems, soaker hoses and hand-held watering wands work well. Emitter-type or DRIP IRRIGATION systems work well with container gardens and widely spaced vegetables like squash and melons. These systems use a series of plastic hoses and directional devices that bring water right to the root zone of plants. They also keep water off foliage and away from weeds that may compete for available moisture. These systems use about half the amount of water consumed by overhead sprinklers. However, it takes some planning to install them correctly and they're relatively expensive. The tubes are frequently cut when digging and cultivating. To prevent damage to the tubes, mark their location. Mulch to control weeds and reduce cultivating. SOAKER HOSES release a very slow trickle of water and must be strategically placed throughout the garden bed. These hoses keep water in the root zone and off the leaves. They reduce loss of moisture through evaporation. They release water to a rather restricted area depending on the soil type, so careful placement is important. Installation does not require the planning of emitter systems and these usually can be put in place at any time of the season. Soaker hoses can be buried 2 to 4 inches deep if put in place before planting. Here, water lost to evaporation is reduced, but buried hoses may be cut accidentally. It takes a long time for adequate water to be delivered to the area. For that reason, it is recommended that the garden be divided into sections so one hose does not water the entire plot. Many larger gardens are watered by stationary or portable sprinklers. Check uniformity of application. Overlap distribution to ensure uniformity. Raise the oscillating-type sprinkler by placing it on some type of platform. Although oscillating sprinklers are inexpensive and require no planning, low water pressure and wind can make this system wasteful. Morning is the recommended time to use this system.   SANITATION Remove diseased plants from the garden to prevent the spread of the disease. Diseased plant materials should not be placed on the compost pile unless the pile is large enough to heat to 140 degrees F, killing disease-causing organisms. Rocks, plastic transplant containers, wooden or plastic stakes, bottles, milk jugs and other objects that somehow find their way into the garden, should be removed. They provide hiding places for insects and slugs. This not only will make the garden a more attractive place, but also will reduce pest populations.   WEED CONTROL Weeds are undesirable in the vegetable garden because they compete with crops for nutrients and water. Weeds also are hosts for both insect and disease problems. Weed control begins at planting time. Intensive techniques of wide-row planting and careful crop spacing can result in the soil being shaded so weed seeds do not germinate, or germinate, but grow weakly. Pull weeds by hand or hoe to control weeds until crops reach a sufficient size to overpower weeds. Shallow hoeing of the top inch or less of soil is preferred. Deep cultivation may bring buried weed seeds to the surface, stimulating germination. Watering techniques directed only to the crop root zone will help control weed growth by limiting water availability. This is more effective during drought conditions if you use a drip irrigation system.   CULTIVATION Cultivate the garden until crops are established and large enough to out-compete the weeds or large enough to be mulched. Every attempt should be made to control weeds before they flower and produce more seeds. Weed stems should be broken or cut as they are pulled or hoed to keep the weed from rerooting. Weeds that propagate by stolons or rhizomes, such as perennial grasses and morning glories, should be used to make COMPOST TEA to ensure that they don't reroot in the compost pile. Dead weeds are a valuable source of organic matter and should be worked back into the soil.   MULCHING Mulching is an excellent way to control weeds. A layer of organic mulch 2 to 4 inches thick or a sheet of black plastic keeps most weeds in check. When weeds do emerge, they are easy to notice and remove. Appropriate mulching materials for use in the vegetable garden include herbicide-free grass clippings, straw, black-and-white newspaper (no glossy pages), compost, leaf humus, LANDSCAPE FABRIC, black plastic and infrared transmitting mulch. Wood chips are excellent for controlling weeds around the periphery of the garden or on garden paths. Organic mulches are recommended since they improve the quality of garden soil as they decay. Mulching also reduces moisture loss. Put organic or synthetic mulches in place after a soaking rain. Organic mulches are most effective when placed over weed-free soil. Since organic mulches tend to keep the soil cool, they should not be placed on the soil until the soil has warmed. Mulched tomatoes have been shown to produce better than unmulched tomatoes. Furthermore, they produce better when mulched with an organic material. Living mulches, such as white Dutch clover and hairy vetch control weeds well. They also add nitrogen to the soil. Living mulches keep the soil cooler and wetter. Although black plastic mulch and infrared transmitting mulch do nothing to improve the soil, they are effective in controlling weeds, especially those that spread by stolons and rhizomes. Some plants, particularly peppers, benefit by being mulched with them. This is because they heat the soil faster. Be sure to cut slits in these mulches to ensure that water can get to the soil around the plant roots. It's important to add organic matter to the soil in the fall if the garden is mulched with black plastic or infrared transmitting mulch; otherwise, the soil may become depleted of organic matter. Mulch is a favorite hiding place for slugs. If slugs are a significant problem, remove the mulch or use a slug bait labeled for use in vegetable gardens. Extension Bulletin 526 gives detailed information on use of mulches.   HERBICIDES There are very few herbicides recommended to control weeds in the vegetable garden. Herbicides must be used with extreme care around edible crops. Read and follow all label instructions. Persistent cultivation will reduce and eventually eliminate even the most persistent weeds.   HARVESTING Timely harvesting will result in superior produce and help reduce plant diseases and pests that thrive on overly ripe produce. Oversized produce has decreased flavor and textural quality. Allowing squash, cucumber and okra to grow beyond the ideal size reduces the plant's productivity. Regular harvesting will promote continued production in some crops.   FALL CLEANUP An important part of the gardening season is the late fall cleanup. First, remove all stakes, string, water bottles, plant containers, cans and paper from the garden. Second, remove all diseased and pest-infested plants to avoid reinfestation the next year. If the compost pile is active and heating adequately, adding diseased and pest-infested materials is recommended. If you're unsure that the pile is heating properly, make compost tea with the diseased and insect-infested plant debris. Turn disease-infested plants into the soil in an area of the garden where susceptible plants will not be grown, such as the flower or herb garden. Fall is an excellent time to incorporate organic matter into the garden soil. Chop and turn under dead plants and leaves, compost, composted manures and leaf humus. Plant a cover crop of cereal or winter rye in late August through September. Annual rye and hairy vetch should be planted in September or October to help prevent erosion and to further improve soil tilth. Cover crops should be turned under before they go to seed or two weeks before crop planting in the spring. Ideally, the garden should be clean and green when November arrives.   CROP ROTATION Crop rotation is a cultural practice that should be included in garden planning. Many gardeners plant the same crops in the same location, year after year. Decreased yields due to increased disease problems can result. Rotating vegetables also benefits the soil by not placing the same nutrient demands on it every season. The key to successful crop rotation is to remember that plants that are related tend to have the same disease and pest problems. The rotation scheme needs to be set up so a crop does not follow another crop of the same family. For that reason, grouping vegetables by family is a good idea. Crop rotation prevents the buildup of diseases that live in the soil. Certain bacteria, fungi and viruses build up their populations during the growing season, while they are living on crops. Disease populations can become established if the same or a related crop is present and becomes infected each year. Crop rotation counteracts this problem. Clubroot is an example of a plant disease that can become established in the soil. It infects many crops of the mustard family. Even without a host plant, the disease spores can remain viable for up to five years  Families of Vegetables Grass Family: popcorn, sweet corn Amaryllis Family: onion, leek, shallot, garlic Goosefoot Family: beet, Swiss chard, spinach Mustard Family: cabbage, cauliflower, broccoli, brussels sprouts, kale, collards, kohlrabi, sprouting broccoli, pak choi, Chinese cabbage, turnip, broccoli raab, mustard greens, rutabaga, radish, horseradish Pea Family: peas, beans Parsley Family: carrot, fennel, parsley, celery, parsnip, celeriac Nightshade Family: eggplant, potato, tomato, pepper Gourd Family (cucurbits): pumpkin, squash, cucumber, melons Composite Family: lettuce, endive, salsify, Jerusalem artichoke The two families that are most susceptible to soil-borne diseases are the mustard and nightshade families. The recommendation is to divide the garden into three sections: one for the nightshade plants, one for the mustard group and one for everything else. Then it is easy to rotate on a three-year schedule.   INSECT CONTROL Insects can cause significant damage to vegetable crops. Bulletin 498, "Home Vegetable Garden Insect Control," lists crops with the insects that cause problems and provides control options. Because pesticide registration with the EPA is constantly changing, it is critical to understand that the crop must appear on the label of the pesticide being used. It is the user's responsibility to read and follow label instructions on all pesticides. When using chemicals in the vegetable garden, remember that you are working with food crops. Accurate garden records will provide the information needed for waiting the correct numbers of days between pesticide treatment and harvest. Pesticides are not the only options for controlling insects. Barriers are used to prevent insects from reaching crops. Barriers include cardboard collars, aluminum foil, row covers, and plastic. Aluminum foil or reflective plastic mulch is used to confuse aphids that transmit viral diseases to squash. Use COLLARS of various materials to prevent cutworms from chewing through the stems of recently transplanted seedlings. Milk cartons opened at both ends or paper tubes can be used as collars, depending on size of transplant. Row covers were originally developed as season extenders. Since then, lightweight versions have been developed specifically to keep insects off plants. These new products provide little protection from cold temperatures. Place row covers over various crops to keep out harmful insects. The material works best when used to protect vegetables, such as greens, that don't require pollination for development of the fruit. Otherwise, the row cover must be removed so insects can pollinate crops, such as cucumbers and squashes. Row cover fabric is effective in keeping aphids, beetles and cabbage loopers off valuable crops. The row cover will promote an earlier fall crop during cool fall weather. Traps and lures are used to attract insects so populations can be monitored or reduced. The chemical attractants used in the traps have no harmful effect on other animals or humans. These attractants may be floral scents or pheromones. Other traps use shape or color as the attractant. Sticky red balls mimic the size and shape of apples. Whiteflies are attracted to anything that is the shade of yellow traffic signs. If a sticky material is coated onto a yellow surface, large numbers of whiteflies can be trapped. Commercially available sticky traps are used primarily to warn the grower of a problem. They are generally ineffective as a control treatment. In some cases, the attractant may actually lure more insects into the garden.   ANIMAL CONTROL Deer, raccoons, woodchucks, rabbits and squirrels may browse in the vegetable garden. The first line of defense against wildlife is to keep them out of the garden area. Locate the garden plot away from areas that are the home of wildlife. Fencing will restrict many mammals, but it may need to be 6" into the soil to deter some pests, such as woodchucks. Commercially available products designed to deter animal pests through scent, sound or touch, are usually only partially effective. A fence around the garden area or the presence of a cat or dog may be more effective choices for control.   DISEASE CONTROL   Integrated Pest Management (IPM) advocates proper cultivation techniques as the first line of defense against plant diseases. Diseases are caused by microscopic organisms and are more difficult to identify than insect pests. Common garden diseases of vegetables include blights, anthracnose, mildew, clubroot, stem and fruit rots and mosaic virus.   PREVENTIVE PRACTICES Vegetable crop diseases can be reduced by following good gardening cultural practices mentioned throughout this chapter. To review, here is a list of practices that reduce disease infection: Choose disease-resistant varieties. Use sterile seed-starting media. Space plants at recommended distances. Use watering practices that keep moisture off foliage as much as possible. Maintain good garden soil structure and nutrient levels. Do not walk through the garden after rains or when foliage is wet to avoid spreading disease-causing organisms. Keep weeds and debris out of the garden and surrounding areas. Remove and destroy any diseased plants immediately. Practice crop rotation. Wash hands after smoking and before gardening. Do not smoke in the garden. Control of insects in the garden is important for disease control. The wounds that insects make in plant parts cause openings where disease-causing organisms enter. Some insects carry diseases and infect plants as they feed. Most diseases can be controlled by the preceding cultural practices. However, there are some diseases that cannot be controlled by these methods. Some plant groups are more susceptible to diseases than others. For example, tomatoes, cucumbers and muskmelons often suffer from disease attacks that must be controlled by pesticides. These vegetables seldom need fungicides for disease control: asparagus, beans, beets, cabbage, cauliflower, carrots, eggplant, lettuce, onions, parsnips, peas, peppers, radishes and sweet corn. To decide if pesticides should be used to control a plant disease and to determine the chemical to use, ask and answer the following questions: Is there a specific disease identified as the cause? Choose a pesticide effective in controlling that disease. How extensive is the crop damage? Can it be tolerated as a blemish? Is the disease in a stage where the selected chemicals can be effective? Diseases can be stopped, but not cured. Treating when the infection is limited may prevent the disease from progressing to a serious level. Fungicides are used primarily to prevent infection from occurring. Are there other ways to control this disease? Removing infected leaves may limit the spread of the disease. These questions point out the need to identify the disease and know its life cycle. Plant diseases are very tricky to diagnose. Even professionals can be fooled. A quick, incorrect decision to use a product may result in no effect on crops, wasted money and unnecessary exposure to a pesticide. Trained garden center staff and Extension agents can identify diseases and pests. Take diseased specimens to them for identification.   FUNGICIDES Many chemicals are available for disease control. These chemicals must be applied before infection occurs. Products available to the home gardener include foliar sprays and powders. Some products are effective against many disease organisms, and are called broad spectrum products. Other products control only a few kinds of organisms. Seed companies often treat seeds with fungicides to prevent or reduce fungal infection that can cause the seeds to rot. Foliar sprays or dusts are applied to leaves and branches of plants. They are washed away by hard rainfall within 24 hours of spraying. Apply all fungicides according to directions on the label. Avoid drift and follow safety precautions. Certain diseases require a preventive application program. Apply every 7 to 14 days during times when infections are likely to occur.
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