Hydroponics

Article By:

Dreschel, Thomas W. Bionetics Corporation, Environmental Monitoring and Research Program, Kennedy Space Center, Florida.

Last reviewed:May 2021

DOI:https://doi.org/10.1036/1097-8542.330600

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• Hydroponics, published June 2014:Download PDF Get Adobe Acrobat Reader

The collective techniques for supplying nutrients and water directly to the roots of plants, without soil or other media. Hydroponics is concerned with the cultivation and growing of plants without soil or other media. Hydroponic systems (Fig. 1) range in complexity from a single plant supported above an aerated jar of nutrient solution to thousands of plants supported above a large area of flowing solution in which pH, temperature, and nutrient concentrations are controlled by using a sophisticated computer system and automated chemical analyses. In hydroponic culture, the precise control of the pH and the concentrations of elements in the solution is critical; all essential elements must be provided in the correct ratios for plant growth. Elements known to be essential are nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese, boron, copper, molybdenum, and zinc. Oxygen in the root zone is also necessary. Methods that utilize an inert medium (for example, sand, gravel, peat, or vermiculite) to provide the root environment, with water and nutrients added in solution, are soilless culture, but they are not hydroponic in the strict sense. See also: Element (chemistry); pH; Plant; Plant growth; Plant mineral nutrition; Soil

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