What Are Hydroponics?


Hydroponics is a form of hydroculture that grows plants using mineral nutrient solutions without soil. Terrestrial plants can thrive in the mineral nutrient solution on its own or in an inert medium, such as perlite, gravel, mineral wool, expanded clay pebbles or coconut husk. Researchers discovered in the 18th century that plants absorb essential mineral nutrients as inorganic ions in water. In natural conditions, soil acts as a mineral nutrient reservoir but the soil itself is not essential to plant growth. When the mineral nutrients in the soil dissolve in water, plant roots are able to absorb them. When the required mineral nutrients are introduced into a plant's water supply artificially, soil is no longer required. Almost any terrestrial plant will grow with hydroponics


The word hydroponic comes from Latin and means working water. Simply put, it is the art of growing plants without soil. Many different civilizations have utilized hydroponic growing techniques throughout history. As noted in Hydroponic Food Production (Fifth Edition, Woodbridge Press, 1997, page 23) by Howard M. Resh: "The hanging gardens of Babylon, the floating gardens of the Aztecs of Mexico and those of the Chinese are examples of 'Hydroponic' culture. Egyptian hieroglyphic records dating back several hundred years B.C. describe the growing of plants in water." Hydroponics is hardly a new method of growing plants. However, giant strides have been made over the years in this innovative area of agriculture.


Throughout the last century, scientists and horticulturists experimented with different methods of hydroponics. One research goal was to grow fresh produce in non-arable areas. This application of hydroponics was used during World War II. Troops stationed on non-arable islands in the Pacific were supplied with fresh produce grown in locally established hydroponic systems.


As hydroponic plants are grown in an inert growing mediums soaked in nutrient solution with a perfectly balanced pH, the plant can uptake its food using minimum energy. This energy cost to hydroponic plants is even less than for plants grown in organic soil with the best fertilizers. The energy expended by the roots in the nutrient uptake process is energy better spent on vegetative growth and fruit and flower production.


Comparing two genetically identical plants, one in soil one in hydroponics, the energy advantage for hydroponic plants is glaring. Faster, better growth and much greater yields are just some of the many reasons that hydroponics is being adapted around the world for commercial food production as well as a growing number of home, hobby gardeners.


Greenhouse hydroponic farming is technology and capital-intensive, but the rewards are ten fold: rich production, efficient water and land use, outstanding green environmental value and most employees only require basic agricultural skills. Since regulating the aerial and root environment is the important concern, production takes place inside enclosures designed to control air and root temperatures, light, water, plant nutrition, and adverse climate.


There are many types of controlled environment/hydroponic systems. Each component of controlled-environment agriculture (CEA) is of equal importance, whether it be the structural design, the environmental control, or the growing system. Not every system is cost-effective in every location. All too often, importance is given to only one or two of the key components, which leads to failure. If improper attention is given to the greenhouse structure and its environment, no hydroponic system will prove economically viable. While hydroponic and CEA are not synonymous, CEA usually accompanies hydroponics. They share the same potentials and problems.