From the Greek roots hydro, water, and meaning work, hydroponics is the science of growing plants in water, without soil. Plants are supported in an inert, non-organic medium such as sand, fine gravel or mica compositions, which are saturated with nutrient solutions for short periods. These solutions typically contain phosphorus, potassium, calcium, urn, sulfur, iron, manganese, boron, and copper. All of the essential foods are available to plant roots quantities.
Hydroponic gardening requires a trough for the plants, an aggregate such as gravel or vermiculite for root support water supply with a pH rating of between 6 and 8.5. Nutrient solutions need to be added with water regularly.
Hydroponics has intrigued scientists because it eliminates the need for ordinary cultivation. Its main cost in the labor is saved by automatics and fertilizing, although installation costs are generally pretty high. So greater crops yield result from hydroponic gardens. Until very recently, corn-acceptance and implementation of hydroponics methods have been impeded by the reliance on chemical nutrient solutions and frequent testing.
With mounting interest in urban agriculture and rooftop food production, however, hydroponics seems destined to assume greater significance. The organic grower can either use a tea made from high-quality compost, or can mix a basic solution of one tablespoon fish emulsion, one tablespoon liquid seaweed, and a teaspoon of blood meal to each gallon of water. The mix varies, depending on the type of plant to be grown. Less blood meal should be used with flowering and fruiting produce than with leafy crops. Other nutrients can also be added: blended eggshells, for example, might be helpful when added to a cabbage crop. Organic hydroponics is very much in a developing stage, and a taste for experimentation is essential.
While soil is cheaper than perlite or vermiculite, it is significantly more difficult to cart up to a rooftop in bulk. Moreover, container soil is prone to rapid leaching and usually requires repeated fertilization, so the actual cost of organic fertilizers for hydroponically grown plants is comparable with that for conventionally grown plants. Hydroponics advocates also point out that since hydroponic roots do not need to grow as far in search of nourishment as the roots of soil-grown plants, planting densities can be more intensive and higher yields can be achieved.
The equipment for hydroponic production can be constructed simply and inexpensively. The container must be elevated slightly at one end and have drainage holes at the opposite end. One-inch plastic pipes with holes drilled every three inches are laid about an inch below the medium and raised at both ends of the box. Smaller rubber hoses coming from the nutrient supply are inserted into the pipe at one end; the upward bend in the pipe at the opposite end stops the flow of the solution. A gravity system for controlling nutrient flow composed of two five-gallon buckets elevated on boxes and standing two feet above the top of the growing container, makes it easy to add nutrients and care for the hydroponic plants.