| |
 |
Browse by Category |
 |
| | |
| |
 |
Browse by Brand |
 |
| | |
| |  | |  |
| |  |
|
 |
| | | Home»Nutrient Film Technique |
| |  |
|
 |
| | Nutrient Film Technique (NFT)
The technique called Nutrient Film Technique (NFT) was developed by Dr Allan Cooper during the late 1960s at the Glasshouse Crops Research Institute in the U.K. In the NFT system a thin film of nutrient solution which contains the plant roots with no solid planting media flows through plastic channels. The root mat develops partly in the shallow stream of re-circulating solution and partly above it.
To maintain the nutrient film is extremely important because it ensures the root system has access to adequate oxygen levels. The key requirements in achieving a nutrient film situation are described by Cooper (1996) as being: “To ensure that the gradient down which the water flows is uniform and not subject to localized depressions, not even a depression of a few millimeters.” The rate of flow of inlet need not be so rapid to avoid water flowing down the gradient.
The research shows that yields will be directly proportional to channel width – the smaller the width, the lower the yields. So the width of the channels in which the roots are confined must be adequate to avoid any damming up of the nutrient by the root mat.
The base of the channel must be flat and not curved. With a curved base because of the shape of the base there will be a considerable depth of liquid along the center of a channel (Cooper 1996).
A primary advantage of the NFT system over other systems is that it requires a greatly reduced volume of nutrient solution. The solution can be more easily cooled during hot summers to avoid bolting and other undesirable plant responses and heated during the winter months to obtain optimal temperatures for growth.
Types of NFT Systems and Gullies
There is a huge range of NFT system designs available in the Hydroponic market. Almost all of them incorporate the use of some type of PVC gully supported by benches in both greenhouse and outdoor situations. The most commonly used type of PVC gully is the white rectangular 150 x 100mm channel.
Many growers take advantage of both square and round diameter downspouts and incorporate these into systems of their own design. Most large commercial growers purchase PVC gullies in bulk and thus reduce costs in this way. These channels usually have pre-punched holes for planting seedlings into and removable lids which aid in cleaning of the system. The choice of gully system or material is usually based on availability, cost, and grower preference.
|
|
|
|
|
