THE N.F.T. SYSTEM (NUTRIENT FILM TECHNIQUE
Today this is the best known system, and when many individuals
talk about hydroponics, they are actually referring to the NFT
In this system, there is a constant flow of nutrient solution and, because of this, there is no need for a timer to switch on and off the pump that controls its circulation.
The nutrient solution is pumped from a container to a channel or gully, inside and on the bottom of which the solution flows continuosly in the form of a very thin film in which the roots are partially submerged. The remaining part of the root system is above this thin film in contact with humid air from which they derive their oxygen supply.
After running through the whole length of the channel, the remaining nutrient solution returns to the container.
With small sized plants, the channel or gully, is usually replaced by a rectangular shaped tube.
Normally, in this system, there is no growing medium, and the plants are generally kept upright in germinating pots or nets from which the root system is suspended in the air inside the channels or gullies with their extremities immersed in the solution.
The great problem with this system is that an eventual electrical power or pump failure would provoke the interruption of the flow of the film of nutrient solution, causing an extremely rapid drying out and death of the plants.
That is why in the design of N.F.T. systems we must consider a backup power supply, like an electrical generator, or a DC powered pump.
Properly designed and constructed, it can be utilized for small and medium sized plants like lettuces and tomatoes.