Water Instead of Soil
Hydroponic gardening systems rely heavily on water instead of soil. Once plants begin sprouting, nutrients are added to the water, which gets directly to plant roots. This method of feeding causes plants to grow faster, since roots don't have to search for minerals in soil. In some systems, plants use no growing medium except air. In others, growing mediums such as vermiculite, coconut fiber, gravel, sand or perlite might anchor plants. There are also soil-less mixes available. In hydroponic systems, letting roots dry out defeats the purpose.
Hundreds of different hydroponic systems exist, but they are all variations on or combinations of six basic hydroponic systems: the wick system, water culture system, aeroponic system, N. F. T (Nutrient Film Technique) system, drip system and the ebb and flow (flood and drain) system. Systems are largely closed, that is, the water, for the most part, is conserved. Because of this, hydroponics uses up to 90 percent less water than conventional growing methods, according to Microfarm Sustainable Research and Education.
The wick system is the most basic kind and is the only hydroponic system that doesn't rely on moving parts. A tray or pot containing plants in a growing medium is suspended over a water reservoir that might simply be larger pot that lacks a drain hole. Wicks draw nutrient-enriched water from the reservoir up to the growing medium and the roots.
Water Culture System
In a water culture system, a Styrofoam raft is floated on the nutrient laden water in a reservoir. Holes in the Styrofoam support plants, roots growing down into the water. Roots receive oxygen from an air pump that bubbles water in the reservoir. This system is often made from an aquarium.
Aeroponic systems are high-tech set-ups that forgo the use of growing medium. Plants suspended over a reservoir are misted frequently and automatically via a timer and pump.
N.F.T. systems use no growing medium. Plants are usually suspended in a tube, the roots growing down to the bottom where nutrients are constantly flowing, pumped into the tube from a reservoir. Excess water runs back into the reservoir.
Ebb and Flow System
The ebb and flow system, which is also known as the flood and drain system, pumps enriched water from a reservoir up into a growing tray, then drains that water back into the reservoir, usually with the help of a timer. The growing tray is filled with plants growing in some kind of medium. People sometimes use separate pots placed in the tray instead.
Drip systems, too, use a medium-filled growing tray to hold plants that get water dripped on to their roots from a water reservoir. The system uses a submerged pump and timer. A recovery type drip system saves and reuses any extra water. Of course, this means that the nutrient levels in the water will change over time, requiring more attention. The non-recovery type system doesn't reuse the water.