NFT Hydroponics: Learn the best and proper techniques for setting up a Nutrient Film Hydroponic system. The Nutrient Film Technique is a tried and true method you can use for all your gardening needs.
How does it work?
In continuous-flow-solution-culture, the nutrient solution constantly flows past the roots.
A popular variation of continuous-flow-hydroponic systems is the nutrient film technique, or NFT. How it works is a very shallow stream of water, containing all the dissolved nutrients required for plant growth, is recirculated past the bare roots of plants in a watertight gully, also known as channels.
Ideally, the depth of the recirculating stream should be very shallow, little more than a film of water, hence the name 'nutrient film'. This ensures that the thick root mat, which develops in the bottom of the channel, has an upper surface which, although moist, is in the air. That ensures there is an abundant supply of oxygen to the roots of the plants.
A properly designed NFT hydroponics system is based on using the proper channel slope, the right flow rate, and the right channel length. The main advantage of the NFT system over other forms of hydroponics, is that the plant roots are exposed to adequate supplies of water, oxygen, and nutrients.
In all other forms of production, there is a conflict between the supply of these requirements, since excessive or deficient amounts of one results in an imbalance of one or both of the others.
NFT hydroponics, because of its design, provides a system where all three requirements for healthy plant growth can be met at the same time (as long as the simple conceptof NFT is always remembered and practiced.)
Photo Credit: Ryan Somma
The result of these advantages: higher yields of high quality produce are obtained over an extended period of time!!
The same design characteristics apply to all conventional NFT systems. While slopes along channels of 1:100 have been recommended, in practice it is difficult to build a base for channels that is sufficiently true to enable nutrient films to flow without ponding in locally depressed areas. So, we recommend slopes of 1:30 to 1:40 be used.
This allows for minor irregularities in the surface. But, even with these higher slopes, ponding and water logging may occur.
The slope may be provided by the floor, or benches or racks may hold the channels and provide the required slope. Both methods are used and depend on plant requirements and also the room or area you build the system in.
As a general guide, flow rates for each gully should be approx. 33 ounces per minute. At planting, rates may be half this and the upper limit of 60 ounces/min appears about the maximum. Flow rates beyond these extremes are often associated with nutritional problems.!
Depressed growth rates of many crops have been observed when channels exceed 38 feet in length. On rapidly growing crops, tests have indicated that, while oxygen levels remain adequate, nitrogen may be depleted over the length of the gully. So, channel length should not exceed 32-48 feet. In situations where this is not possible, the reductions in growth can be eliminated by placing another nutrient feed half way along the gully and reducing flow rates to 33 ounces/min through each outlet.
For more information on Hydroponic Systems and Set Ups, go here.