The nutrient film technique (or NFT) was developed in the mid 1960s and is still extremely popular among indoor growers, to this day, for its easy set-up and simple maintenance. NFT is simply plant growth in a constant flow of nutrient enriched water.
The NFT growing system takes place on a flat surface, much like a table, with a series of 1 millimeter to 3 millimeter deep gullies, running lengthwise across its surface. The roots of each plant are fixed in a root cube and placed in pre-drilled holes within the gullies. The nutrient stream is then fed to the plants via a submersible pump. The pump releases water at one end of the table causing the stream to spread evenly to each channel, flowing downward and submersing each plant in approximately 1-3 millimeters of nutrient-rich water. Once the stream reaches the end of the table it is caught at the bottom in a reservoir or tank and then re-circulated. NFT feeds plants constantly because the pump is continual.
Since the NFT grow system doesn't require a grow medium, the over saturation of plant roots is rare and the cost is minimal. However, NFT systems should be monitored regularly in case of a power failure, which would shut down the NFT pump and starve the plants.