Hydroponics (from the Greek words hydro water and ponos labor) is a method of growing plants using mineral nutrient solutions, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel or mineral wool.

The term “hydroponics” was first used by Dr. W.F. Gericks in the late 1930s to describe a method of growing plants with roots immersed in an aerated, dilute solution of nutrients. Today, hydroponics is used in commercial greenhouse vegetable and plant production around the world.

A hydroponic production system may use a wide variety of organic and inorganic materials. The nutrient solution, rather than the media in which the plants are growing, always supplies most of the plant nutrient requirements. This method of growing has also been referred to as nutrient-solution culture, soilless culture, water culture, gravel culture and nutriculture.

Plants absorb essential mineral nutrients as ions in water. In natural conditions, soil acts as a mineral nutrient sponge, but the soil itself is not essential to plant growth because clay, sand, rocks and fibrous material can restrict oxygen and impair root growth. When the same organic mineral nutrients are dissolved in water, without the restrictive properties of soil, plant roots are able to absorb them freely. Providing plants the required organic mineral nutrients in the water supply means that soil is no longer required for the plant to thrive. Almost any terrestrial plant will grow in a hydroponic system.

Hydroponic culture is not new. One of the first experiments in water culture was made in England in 1699. By the mid-19th century, Sachs and Knop, the real pioneers in the field, had developed a method of growing plants without soil.

There are several advantages to hydroponic culture. Some of the problems associated with conventional soil culture such as poor soil structure, poor drainage and non-uniform texture, as well as weeds and soil-borne pathogens, are eliminated. In automated hydroponic culture, some of the watering and fertilizer additions can be computerized, reducing labor input.

The biggest advantage of the hydroponic method is that crop yields are increased many times over those of conventional agriculture. For example, according to Mother Earth News, the yield per acre of tomatoes grown in soil is from five to ten tons. With hydroponics, the harvest is from 60 to 300 tons. For cucumbers, the equivalent figures are 7,000 pounds compared with 28,000 pounds, and for lettuce, 9,000 pounds and 21,000 pounds.