With the first successful application of hydroponics techniques in the 1930s the stage was set for a paradigm shift in crop production from conventional geoponics or cultivation in soil to hydroponics or soil less cultivation. The first crops to be commercially harvested with hydroponics included tomatoes and peppers, but the techniques were soon successfully extended to other crops such as lettuce, cucumbers and others. It was not long before hydroponics techniques were successfully adapted even to cut flowers production; in fact any plant can today be grown hyrdroponically.
Commercial hydroponics systems can be classified into bare root systems comprising nutrient film technique (NFT), deep flow and aeroponics systems and substrate systems.
Bare root systems do not use media to anchor the plant roots; the roots are left bare while in substrate systems plant roots are anchored in media such as perlite, vermiculite, sawdust, peat etc. Hydroponics is basically all about growing plants in a controlled environment and this is best provided outdoors in greenhouses that can incorporate several means to monitor, regulate and control the environment inside them. For instance, the air entering the greenhouse can be filtered to exclude entry to pests and parasites that can harm plant growth. Such means help provide optimal conditions for plant growth both in and out of season. In fact, hydroponics allows cultivation throughout the year which makes for year round availability of hydroponically grown produce at all major supermarkets across North America. Valued at 2.4 billion dollars the hydroponic greenhouse vegetable industry has a growth rate of 10 percent per year and accounts for nearly 95 percent of the greenhouse vegetables produced in North America.
The extension of the growing season is not the only advantage contributing to the growing popularity of hydroponics production with both growers and consumers. There are several additional advantages as well including nutritious, healthy and clean produce, improved and consistent vegetable quality and elimination of the use of pesticides and herbicides. Pesticides and other chemicals used in conventional agriculture have an adverse environmental impact; the run off from these chemicals contaminate groundwater supplies. Commercial hydroponics systems eliminate these toxic chemicals and contribute substantially to keeping the groundwater free from contamination.
Commercial hydroponics systems have proved more productive than conventional systems of agriculture not only in the laboratory but even in actual practice. Most commercial hydroponics greenhouse facilities are built large to take advantage of economies of scale; typically these cover areas more than 10 acres while smaller ones measure around two acres. In the research greenhouse, yields with hydroponics techniques have averaged around 20 to 25% higher than in conventional soil cultivation. In actual commercial practice, however, over a number of years, the yield of hydroponically grown tomatoes can be more than double that of soil based systems due to the reduced turnover time between crops, better nutrition and crop management. Additionally commercial hydroponics growing techniques are also less demanding of chemicals for root zone sterilization and control of pests, weeds etc.
The dramatic increase in yields with hydroponics is best illustrated if we consider the actual production figures of soil grown and hydroponically grown produce. Field grown tomatoes average yields ranging between 40,000 to 60, 000 pounds per acre; on the other hand top growing hydroponics facilities in the US and Canada report average yields of more than 650,000 pounds of tomatoes per acre. Additionally, given the fact that only 10 years ago top hydroponics producers were producing around 400,000 pounds per acre, the increase in yields with improvements in growing practices has been truly phenomenal. Similar production figures can be quoted for other agricultural produce like cucumbers with 10,000 pounds per acre for field production and 200,000 per acre for hydroponic greenhouse yields. Hydroponics lettuce and pepper yields too average around four times the corresponding yields of agricultural production.
Given the number of advantages of hydroponics it is not surprising that hydroponics techniques are increasingly finding favor for commercial food production in many countries all over the world. According to recent estimates countries having substantial commercial hydroponics production include Israel – 30,000 acres, Holland 10,000 acres, England 4,200 acres and Australia and New Zealand around 8,000 acres between them. The fastest growing area for commercial vegetable greenhouses is Mexico. There are several reasons for this including free trade and favorable winter conditions that attract vegetable growers in large numbers. Mexico has summers that are considered hot in the summer, but with greenhouses located at the right altitudes vegetables can be grown in the hot summers as well as the cold winters. Though much of the produce comes from low tech plastic houses, many of these greenhouses use hydroponics technology, which indicates the growing popularity of hydroponics in commercial food production.