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�r..e�Tn�,ri 550,000. There are four types: 1) vacuum template (price range: $1,000— $5,000), 2) vacuum tips or needles ($8,000 - S 13,000), 3) vacuum cylinder or drum ($18,000- 550,000), and 4) electric eye ($10,000—$13,000). The least expensive type is the vacuum template. With this kind of seeder, the seed is scattered over a template that has small indentations on its surface. A vacuum holds the seeds in the indentations, while extra seed is knocked off. When the vacuum is turned off, the seeds drop into place in the plug tray, so the entire tray is planted at once, There are also manual wand seeders that use the vacuum needle system to sow one row of seed at a time. They cost less than $1,000. It is possible to make a simple seeder out of plastic. Dr. Charles Marr developed a planting template in the early 1990s at Kansas State University. Here are his specifica- tions for making a seeder: "The template consists of two sheets of 3 -mm acrylic plastic cut to rectangular dimensions of the seed flat. The upper sheet has a 6 -cm -tall 'wall' glued to the outside with a small opening in the wall at one end, so excess seeds can be poured out. The bottom sheet is held in place by four glued tabs on each side, so that the bottom sheet could slide later- ally. The bottom sheet is left slightly longer with a slot cut as a handle." Holes that are the same size or slightly smaller than the seed that is to be used should be drilled in the plastic. The method of operation is simple: The top and bottom sheets are kept out of alignment. Then the seeds are poured onto the top sheet and rolled around until all the cavities are filled. Excess seed can be poured off. The bottom sheet is then moved into line with the top, and the seeds fall through both sheets and onto the seed mix in the plug trays. Nutrition: Organic Fertilizers for Container Systems There are four basic ways to fertilize containerized plants: incorporate, topdress, liquid feed, and foliar feed. In bed- ding plant culture, fertilizer incorporation in the mix com- bined with liquid feeding should provide sufficient nutri- tion. Organic fertilizers that can be incorporated to provide nitro- gen include: alfalfa meal, blood meal, cottonseed meal, feather meal, hoof and horn meal, soybean meal, and animal manures, among others. Materials that provide phosphorus include oak leaves, bone meal, shrimp wastes, residues from raw sugar, and various forms of rock phosphate. Greensand, granite meal, soybean meal, ash from orange and potato skins, unleached wood ashes, Sul- Po- Mag(ID, and tobacco (stems, leaves, and stalks) all provide potassium. Unless a recognized organic soil mix recipe is used, several experimental batches that compare different fertilizers and rates of incorporation should be tried on a test group of plants. The ATTRA publication Organic Potting Mixes pro- vides numerous recipes for soil and fertilizer mixes. In liquid feeding, nutrients can be delivered by: 1) propor- Page 8 3 2 tioning through drip lines, 2) proportioning through watering hoses, and 3) drenching (from a measuring cup or bucket). Soluble fertilizers may be applied at each watering (known as fertigation or constant liquid feed) in a diluted solution or on a seven to ten -day basis with a concentrated solution. Nitrogen is the main nutrient that is supplied through liquid feeding. Solu- ble organic nitrogen sources include fish powder, fish emul- sion, bat guano, seabird'guano,.worm castings, and manure teas. Phosphorus is available for liquid feeding by using high phosphorus bat guano. Foliar feeding can be used to supplement soil and liquid fertili- zation, especially where certain nutrients are deficient and must be incorporated into the plant quickly. Filtered solutions of ma- nure, seaweed, fish powder, and fish emulsion can be used. Seaweed is an excellent foliar material because it contains growth hormones (auxins, gibberellins, and cytokinins) as well as trace elements. Research suggests that foliar feeding pro- grams enhance plant resistance to pest and disease attack. Compost teas are gaining popularity as a foliar feed primarily for their disease - suppressive characteristics. New Research on Fertilization A study conducted in 1998 at the University of Georgia found that nitrogen, rather than phosphorus and potassium mainly determined growth of plugs. The report recommended that growers focus their fertility programs on nitrogen and reduce phosphorus and potassium applications. Often, there are seasonal variations in growth, and the fertiliza- tion system must take this into account. A recent study per- formed in Florida showed that spring -grown tomato seedlings respond linearly to increased nitrogen fertilizer. In other words, the more N applied, the more the plants grow. (The researchers used 15 -75 mg/liter of N.) Ir_ fall -grown plants, however, the opposite -is true. Researchers believe that increased light and temperatures in the fall were responsible for some of the differ- ences in growth patterns. Other research has shown that any- where from 75 -400 mg/liter of N produces the largest tomato seedlings and often increases early yields. Too much nitrogen, however, attracts aphids. In an English study, cabbage seedlings were fertilized with conventional fertilizer, dried blood (applied in a liquid form), and hoof and horn meal (incorporated into the potting media). Dried blood applied at a rate of 3 grams /liter, three times a week, increased plant growth at about the same level as con- ventional fertilizer. In 1993, Premier Peat Moss in Canada conducted research on organic wastes from the agri -food industry and their ability to fertilize greenhouse tomato transplants. The researchers found