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ADVANCES AND USES OF HYDROPONICS Commercial Hydroponics Hydroponically grown produce is available at all major supermarkets across the country regardless of the season. In North America, 95% of greenhouse vegetables are grown hydroponically. The hydroponic greenhouse vegitable industry valued at over $2.4 billion dollars and is growing at 10 percent per year. The industry is expanding because it is economically productive. Controlled environments and controlled growth techniques maximizes production and is much less labor intense. In addition, the resulting produce is clean, healthy and nutritious, and growing hydroponically significantly conserves the earth's resources. Increased yields, improved and more consistent quality, and elimination of herbicides and pesticides, are major advantages of using hydroponic growing methods for commercial food production. Because hydroponics is almost always used with controlled environments such as greenhouses, the additional major benefit of extending or eliminating growing seasons provides continuous crop production, which again provides extensive increases in productivity. Runoff of phosphates, fertilizers, and pesticide residues from large commercial farms have a serious environmental impact, especially on groundwater contamination. By greatly reducing the use of agrichemicals, hydroponics is more environmentally friendly and results in safer vegetable crops as well. The economic viability of using hydroponics for commercial crop production became evident in the 1930's. The first economically viable commercial hydroponic systems were used to produce greenhouse-grown tomatoes, cucumbers, lettuce and herbs. These, along with peppers, are still the mainstays of commercial hydroponic vegetable production. Hydroponic systems were quickly applied to cut flower production where increased yield and soil sterilization were major issues. Initially, the production of bedding plants and potted flowering plants moved from a soil based system of production to "a soil-less media" consisting of a blend of peat moss vermiculite and perlite. Next, fertilization moved from mixing fertilizers in the soil-less mix to applying nutrients dissolved in the water, basically hydroponics. The application of these hydroponic techniques saved on water and fertilizer and resulted in more uniform crops. More recently, the use of sophisticated flood and drain systems and crop specific nutrients means the virtually all potted flowers and bedding plants grown in the United States utilize some form of hydroponic technique. Commercial systems can be divided into two classes, bare root systems and substrate systems. Many different methods can be used for a wide variety of crops. Bare root systems include nutrient film technique (NFT), deep flow, or deep pond, and aeroponic systems. Deep Pond and NFT are the most popular for commercial lettuce and herb production. Substrate systems use a media such as rockwool or perlite. Other substrates include sawdust, peat, coir, sand, and technically any other media that, specifically, is not soil. Although flood and drain and NFT systems are sometimes used, drip irrigation with rockwool or perlite is most commonly used method for the production of tomatoes, peppers, and cucumbers, as well as cut flowers. Flood and drain systems are mainly used in the production of potted flowering plants and bedding plants. Although very popular with hobbyists, aeroponics is rarely used in commercial greenhouse production. |