Nutrient Film Technique, or NFT, is a versatile hydroponics system that anyone can use with a bit of knowledge and know how, and it’s not hard to learn. Similar to an Ebb and Flow system in that the this system also uses a pump to deliver fertilized water to the grow tray and a drain pipe to recycle the unused nutrient solution. The difference is that in NFT the nutrient solution is continuously flowing over the roots. This is accomplished by using gravity. The grow tray is placed at an angle to allow the water to flow down towards the drainpipe, and a new solution is constantly being pumped into the high end of the tube.
The nutrient solution flows in a thin film over the roots, ensuring that they are watered and fed but not completely soaked. The thin film ensures that the upper part of the roots will remain dry and have access to oxygen in the air. Nutrient Film Technique works best if you choose plants that do not require a lot of support- lightweight, fast-growing plants that can be harvested quickly. If you want to grow plants such as tomatoes or squash, just make sure that you have proper support systems in place such as trellises. The roots are not suspended in a growing medium in this system, so they cannot handle supporting a lot of weight from a top-heavy plant.
Nutrient Film Technique uses tubes or channels instead of flat trays for the grow tray. This makes it easier to set it at an angle and to make sure that the nutrient solution flows directly to the roots without wasting any of it. Most often in DIY systems, a round tube or PVC pipe is used, with holes drilled to fit the net pots and seedlings. This has the advantage of being cheap and readily available to the home hobbyist.
You can either place seedlings directly into the holes of your PVC pipe or channel or for greater stability plant them in net pots and place the net pots in the holes. Most people do not use a growing medium with NFT, but let the roots fall directly through the net pots and onto the film. If you choose to use a growing medium, use it sparingly and make sure that the roots have plenty of room to fall through the bottom of the pot. Whichever way you choose to plant your seedlings, make sure to check and trim the roots often to prevent out of control growth that can clog the system.