NFT
A very shallow stream of water containing all the dissolved nutrients required for plant growth is recirculated through a channel containing the roots of plants suspended from above. The plants are often suspended with the use of pots filled with perlite or clay pellets and are mounted on the top of the round or square PVC channel. A well designed NFT system uses a well calculated slope, and flow rate. NFT has proved to be commercially successful for an array of vegetable and fruit production, leaf crops and micro-greens.
Aeroponics
Plant roots are continuously saturated with a mist of nutrient solution or water. The method uses no grow media like clay pellets or rockwool and merely entails growing plants with their roots suspended in a closed chamber. Aeroponics has proved to be commercially successful for an array of cloning, seed germination, leaf crops, and micro-greens.
Deep Water Culture
Plant roots are fully suspended in a solution of constantly circulating nutrient-rich, oxygenated water. Common designs most often use plastic buckets with the plant suspended from the center of the bucket lid. Buckets are then chained together with the use of Vinyl tubing and heavy duty in-line water pump. Plants in DWC can grow much faster because of the high amount of oxygen that the roots receive.
Ebb and Flow
NFT is the most common form of hydroponics. Its design is most often a tray sitting on top of a reservoir that is filled with water or a nutrient solution. The tray is filled with clay pellets or large cubes of rockwool. At regular intervals, a timer will turn on a pump to fill the upper tray with the water or nutrient solution. After is filled, it will then drain, thus exposing the plants roots to cycles of both water and oxygen.