NFT is an abbreviation of Nutrient Film Technique. This hydroponic method of growing involves running a thin layer of nutrient, no deeper than a few mm, across a surface which the plant is placed upon. This is usually a trough or special sheeting material.
The plant roots grow into the thin layer of nutrient and take up all that they require. The technique uses very little growing media as it mainly used to support the young plant. Stonewool cubes are commonly used as well as clay filled net pots. Larger plants such as tomatoes will require additional support as they grow bigger.
The NFT gullies need to be built on a slope so that gravity will feed the nutrient back to the main tank. This is recommended to be between 1:20 and 1:40 gradient. The nutient is pumped from the main tank to the top and of the gullies and this will run back to tank with an ideal flow rate of 2 litres per minute.