Words News : Hydroponic

"The process of growing plants in sand, gravel, or liquid, with added nutrients but without soil"  -oxford dictionary

Hydroponics may simply be described as growing plants with nutrients and water, and without soil. The water must be delivered to the plant root system. The root system may hang directly in the nutrient solution, be misted by it, or can be enclosed within a container or a trough which is filled with a substrate [a replacement for soil]. The substrate may consist of many different types of materials, such as perlite, sand, sawdust, wood chips, pebbles, or rockwool. All substrates must provide good water holding capacity, yet be porous for gas exchange. Between watering events, they become the storage location of water and nutrients for the plant root system. The roots grow within the substrate to secure the plant within the container, or trough.  -Arizona University-

Hydroponics is a subset of hydroculture and is a method of growing plants using mineral nutrient solutions, in water, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only, or in an inert medium, such as perlite or gravel. -wikipedia-