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What is hydroponics?

Hydroponics is the growing of plants without soil. It dates back to antiquity. The Hanging Gardens of Babylon, the Floating Islands of the Aztecs, and the Floating Gardens of China are famous examples. After several millennia of experimentation, the science of hydroponic methods for production of food and ornamental plants finally attained levels in the mid-1930’s that supported newfound practical interests. Vigorous research and development in this area have continued to the present.

Every hydroponic installation, regardless of size or sophistication, must supply plants with five essential components; water, nutrients, root support, air, and light. Various systems are available to deliver these components in a reliable, regulated manner while excluding contaminants that might lead to disease and/or diminished productivity. Cleanliness is of major importance.

Water, of high quality, is the key to each system. It serves as the carrier of nutrients and dissolved oxygen and to keep plants hydrated. It must be monitored constantly to assure that proper pH is maintained for optimum availability of nutrients to the species being grown. It can be delivered by drip, ebb and flow, or immersion methods.

It has been found that plants grow better when their roots are contained in an inert support medium rather than in a plain stream of nutrient solution. Materials that can be used as support include rockwool, perlite, river sand or gravel and pebbles. Ocean sands are not recommended.

Oxygen must be supplied to plant roots. This can be accomplished by aerating the circulating nutrient solution or by periodically exposing plant roots to filtered air.

Light of the proper intensity and wave length is critical for optimum plant growth. Much research has been carried out in this area, and special lamps and supporting equipment are available.

Plastic materials are usually recommended for construction of hydroponic systems. Corrosion of common metals, which should be avoided, could be a major source of contaminants.

Almost any garden plant can be grown hydroponically. Leafy vegetables and herbs that grow rapidly are especially good candidates. Tomatoes, peppers, beans, and peas also grow nicely with proper care.

Hydroponics has applications for commercial production as well as for the home gardener.