The
cultivation of plants in a liquid
nutrient solution instead of
soil.
A carefully prepared
aqueuous solution of all the nutrients required for healthy growth is used, usually in conjunction with an
inert medium (such as
sand or
gravel) which provides support for the plant's
root system.
On a small scale, the
solution is simply poured over the
substrate and the excess allowed to drain into containers for re-use.
On a
commercial scale, this is done by an automatic pumping system in which the solution is
monitored to maintain nutrient levels and
acidity.
Hydroponics enables crops to be grown in
arid regions, or where the soil is
infertile or polluted /
toxic. However, its comparatively high costs are a
limiting factor, and hence almost all hydroponics work is with high value plants such as
vegetables and
flowers.