The Nutient Film Technique (NFT) is a classic hydroponic system that is one of the first systems ever developed for hydroponic growing. Its simple design and ease of use make it a good choice for growers of all levels. The NFT system works by constantly running a thin layer, or film, of nutrient enriched water at the rate of about 1 liter per minute over a channel or table where the roots of a plant are resting. The nutrients are absorbed by the plant's roots structure as the water passes by on its way to the other end of the channel or table. The nutrient solution runs off the far edge of the table into a reservoir beneath. A water pump in the reservoir forces the nutrient solution from the reservoir back up to the table above, where it can begin the process again. Plants using this system are usually kept in net pots or rockwool blocks to allow the top of the plant to rest above the nutrient solution, while the roots are constantly exposed below.
NFT systems are beneficial because they are easy to use and inexpensive to set up. NFT systems allow an ample supply of nutrient solution to the pants, while also allowing some oxygen to reach the upper roots of the plant. However, the NFT system also has its drawbacks and should be carefully monitored and maintained. Because the bottom roots are constantly submerged in water, they may not be getting the extra oxygen necessary to allow for accelerated growth. Also, since the lowest roots are without a medium they must constantly be exposed to moisture and nutrients or they will quickly die. A failed or clogged pump can prove to be disastrous in a short period of time.