What Does Nutrient Film Technique (NFT) Mean?
The nutrient film technique (NFT) is a hydroponic growing technique where a small, shallow stream of
nutrient-rich water is recirculated over roots through a channel, gutter, or tube.
Developed in the 1960s by Dr. Allen Cooper, the NFT has
become a standard practice essential to hydroponic cultivation. It is one of the six main types of hydroponic systems and is known for its efficient use of water, ease of set up, and accurate feeding results.
In an NFT set-up, a small, shallow stream (film) of nutrient-rich water is provided to plant roots via a long channel, gutter, or tube. NFT systems are usually all-in-one, closed systems, where a large container holds the pump and nutrient mixture within the same system, facilitating a continuous flow of aerated nutrients to the roots that are housed in a long narrow channel. The runoff nutrient mixture is then lead back into the main water container.
The nutrient film technique is also known as gutter NFT.
Maximum Yield Explains Nutrient Film Technique (NFT)
The nutrient film technique (NFT) is similar to the ebb
and flow system in that it utilizes a pump to move nutrients in a continuous,
constant flow. The difference with NFT is
that the solution flows directly over the roots. NFT is a common system of choice for cannabis growers.
NFT uses shallow tubes that are slightly angled so that the pump moves the nutrient solution to the higher portion of the system. The nutrient solution gradually moves by gravity to the lower portion. A tube system with holes bored for the plants is used instead of trays, mainly because this system is easier to angle for proper flow over the roots.
Most horticulturalists plant directly through the holes, but it is okay to use net pots, and many horticulturalists use no planting medium (e.g., potting soil) with the nutrient film system. The roots fall through the net directly into the nutrient solution. The nutrient solution does not completely soak the roots. The film ensures that the entire root is not submerged so the upper part of the roots remains dry.
Because it contains moving parts, NFT is considered an active system. The main drawback being that in a power outage, entire yields can be destroyed if there is no back-up plan. Passive systems are those without moving parts such as wick systems, which are the simplest hydroponic systems and use a cotton wick to move the water. The wick system is often used for teaching
purposes or as a simple do-it-yourself method for home gardeners.
When using the nutrient film technique it is important to not try to grow heavy
plants that require a lot of support because the roots
are not in a medium that can sustain the weight of a heavy plant. It is necessary to use a self-standing trellis to support plants with heavy fruits such as tomatoes.