Nutrient Film Technique (NFT) Hydroponics | Resource and Information
Nutrient Film Technique (NFT) Hydroponics
Resource and Information
The NFT (or Nutrient Film Technique) hydroponic system is one of the basic types of hydroponic systems that are available and known today. It is closely related to the deep water hydroponics system in that it circulates water directly past the roots of the plants. However, it uses a constant circulating stream as opposed to a stagnant nutrient solution in order to feed the plants. It gets its name from the small amount of water (no thicker than film) that circulates through the plants.
The main component of the NFT hydroponic system is the channel that is used to direct the nutrient solution past the roots. It needs to be water tight so there there aren’t any leaks. In addition, it needs to be light-proof so microorganisms and algae don’t collect and block the flow of water. It also needs to be wide enough that the thin film of water has enough nutrients for all of the plants.
The slope of the channel is pretty important. Ideally, this will be around 1:100, but it can be hard to get something with such a little slope that will be stable and dependable. In practice, something closer to 1:30 or 1:40 is actually used. You want to stream of water to be slow enough that the plants can readily absorb the nutrients, but not too slow such that the water becomes stagnant.
For home usage, it is common to use simple rain gutters.
Along with the other hydroponic systems, the nutrient film technique hydroponic system needs a container to store all of the nutrient
You also want it to be small enough that you don’t waste a lot of nutrient solution when you do periodic cleaning or flushing of the container. Typically, you will want to flush the entire system every 2-3 weeks to remove the nutrient salt buildup and toxins that accumulate in the recycled solution.
Lastly, you will want to position the reservoir beneath the plants that you are growing so it is easy to drain. The system typically uses gravity to move the solution past the roots and at the bottom of the channel there is a drain the recycles the solution back into the container.
You will want to use the same types of pumps as the other systems. Typical aquarium pumps or industrial pumps will work great. It doesn’t have to be that powerful since it will only need to pump a small amount of water to the top of the channel and let gravity do the rest.
Make sure to buy a high-quality pump from a known manufacturer to reduce the chances of clogging and pump failure.
The plants in this system will need some medium to attach their roots. The most common inert medium is rockwool, but peat moss has also been known to work well. In general, just find a known brand and it will work out just fine.
It is most common to see leafy vegetables such as lettuce, chard, or kale in an NFT system, but larger plants such as peppers and tomatoes have been known to flourish as well. Just ensure that you have the right type of growing medium, a large enough container for a mature plant, and a large enough reservoir to keep the nutrients flowing.
The NFT system is very simple using only a few pieces and letting gravity do most of the work. This means that it has a relatively low failure rate (aside from the pump) and as long as you keep up the maintenance and replace fault parts quickly it won’t affect the harvest.
The system is relatively soundless as well since the only moving part is the pump. It will be at a constant volume as well so it is relatively easy to get used to.
There are also a lot of benefits for the plants that are fed in this system as well. Due to the enclosed channel and low stream of water, the roots have access to a relatively humid environment and are moist most of the time. In addition, since much of the nutrient solution is suspended in air, there is plenty of opportunity for oxygenation.
You need to be careful so that the water doesn’t pool inside the channels and there is enough flow for the constant cycling of new nutrient solution past the roots.
If the pump fails, you will want to replace it quickly otherwise the plants may die. If the weather is especially hot, a dead pump can ruin a crop in just a few hours.
Any plants that have a large or deep root mass (such as carrots) don't grow very well due to the limited depth of the nutrient channel. Instead, you will want to choose one of the other methods such as aeroponics.
Since the nutrient solution is recirculated and recycled toxin buildup and nutrient salt buildup can occur. Ensure you are flushing the system every few weeks or keeping an eye on the pH to catch any issues.
We have had a great time today outlining the nutrient film technique hydroponic system for all of you. It is a great way to get into hydroponics and provides something a little bit different than the standard deep water culture or ebb and flow systems. Feel free to reach out to us with any questions, comments, or concerns.