Nutrient Film Technique (NFT) is a method that has probably been around longer than any other hydroponics methods. You will hear sales people at the grow stores, say it is the “Old School Method.” This method is also popular among commercial growers because of its versatility and aggressiveness. NFT consists of a long grow chamber such as PVC pipe or channel. At evenly spaced intervals along the pipe, there are holes containing either collars, baskets, or in some cases, grow media in which plants are held. The roots of the plant hang down in the hole and a shallow stream, or “film” of water is run across the root tips.
Advantages of NFT
- The cost of building a NFT system is low.
- Constant water movement keeps water from going stagnant.
- You can have a lot of plant sites.
- You can use any grow media to hold the plant.
- You can reuse the water.
- Doesn’t have parts to clog.
- Great with organics.
- No timer to worry about breaking, because the water is always flowing.
- Grow media is not required.
Disadvantages of NFT
- pH fluctuation/ monitoring required.
- If the pump breaks, your plants will die quickly. This is because there is no media to hold water.
- May need a chiller.
- Plants with short roots will need to be top fed or drip line incorporated, until roots grow to bottom of PVC.
This is the kind of hydroponic system most people think of when they think about hydroponics. N.F.T. systems have a constant flow of nutrient solution so no timer required for the submersible pump. The nutrient solution is pumped into the growing tray (usually a tube) and flows over the roots of the plants, and then drains back into the reservoir.
There is usually no growing medium used other than air, which saves the expense of replacing the growing medium after every crop. Normally the plant is supported in a small plastic basket with the roots dangling into the nutrient solution.
N.F.T. systems are very susceptible to power outages and pump failures. The roots dry out very rapidly when the flow of nutrient solution is interrupted.