Hydroponics (from the Greek words hydro water
and pono 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 stone or rock wool, expanded clay, or coconut coir.
Plant physiology researchers
discovered in the 19th 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 for the plant to
thrive. Almost any terrestrial plant will grow with hydroponics.
Hydroponics is also a standard technique in biology research and
teaching.
When most people think of hydroponics, they
think of plants grown with their roots suspended directly into water
with no growing medium. This is just one type of hydroponic
gardening, known as N.F.T. (Nutrient Film Technique). There are
several variations of N.F.T. used around the world and it is a very
popular method of growing hydroponically. What most people don't
realize is that there are so many other methods of hydroponic
gardening. Some of the other more popular forms are Top Feed Drip,
Deep Water Culture (DWC), Ebb & Flow, and Aeroponics.