What Is The Nutrient Film Technique

What Is Nutrient Film Technique

One of the many hydroponic methods available is the Nutrient Film Technique or NFT. This system is known as a continuous flow system. This means that unlike some other hydroponic setups it supplies the plants with a constant flow of nutrients. This is usually a system for advanced growers as it can be a touch tricky to set up, but the results are unrivalled. In fact, this method is thought to be the most productive method used today.

How Does NFT Work?

Unlike some systems that will expose the roots alternatively to air and nutrient liquid or fully submerge them, this system does both at once. It allows the roots to be constantly exposed to air as well as constantly submerged in nutrient liquid. The plants are grown in what are essentially troughs and through the bottom, there is a constant stream of nutrient liquid. This means that the roots have the air they need to be hungry, and they have a constant source of food available to them.

The system uses gravity to help the flow of the nutrient solution. This means that the trough has to be on a slight slope. If the solution becomes stagnant or pools around the roots it can cause rot and stop the plants from absorbing any nutrients at all. This is where it can get a little tricky, growers must ensure there is absolutely no way for the solution to pool. Any slight dips or different angles in the set up could cause fatal stagnation. Of course, the gradient of the slope will depend on the area the set up is in and if it uses a sloped floor or a sort of scaffolding.

It is usually a good idea to not go in for too long a trough. The longer the channel the plants sit in the less oxygen the roots will receive. It also means that by the time the nutrient solution reaches the end it will be depleted. The final plants won’t receive as much food as the earlier ones.

Finally, we need to think about the flow rate, the speed at which the film of nutrients flows through the trough. If the plants are given too much solution they can become overfed and start locking out nutrients. Of course, if the film is too thin they simply won’t get the food they need. This flow rate will be affected by the gradient and the pump as well as the length of the trough.

Pros of NTF

  • Once it is ready to go it is surprisingly simple to keep happy.
  • It is very efficient and keeps water loss to a minimum by recycling liquid.
  • It is also extremely energy efficient and will keep the bills low.
  • The growth and yields are more impressive than with other systems.
  • Because the medium is always on the move bugs and pests can’t set up home.

Cons of NFT

  • As with many hydro systems, a power outage will ruin everything and kill the crop.
  • The air, water and nutrients required for all hydro setups need to be more finely balanced than with most other hydroponic growing methods.
  • Since this system is more delicate it demands a higher level of understanding of hydroponic systems. This is why it is recommended for those who have already used systems such as Wick system or Deep Water Culture.


There is more to setting up an NFT system than we can really cover today, but here are the basics. Setting up a DIY system is definitely possible but takes a fair bit of planning and no how.

As with most hydro systems we simply need little baskets with an inert growing medium for our plants to sit in. We then use tubes to act as our plant holsters and channels for the nutrient solution. The tube is then mounted at an angle over a reservoir where the nutrients solution will drain back to after feeding the plants. We insert a draining tube at the bottom of the gradient to allow the nutrient solution to flow into the reservoir.

The reservoir is equipped with a pump and possible an airstone to imbue the solution with a little extra oxygen. The air pump will push the nutrient solution through, reinvigorated, and up through a pipe that leads to the top of the gradient tube. Thus there is a cycle of nutrient solution that works as a film over the base of the roots feeding them nutrients.

This may all sound very simple but there is a lot of maths involved in setting up the structure. We need to ensure the angle is exactly right, that the nutrient balance is right, that the cups are the right height above the film and that we have to correct flow rate.

We also need to regularly check on the system to ensure there are no blockages in the pipes. If a blockage occurs the solution could pool, in turn ruining the roots.

There are a number of different and interesting ways that we can mount our NFT systems. Many go for a wood frame tower that allows for a sort of helter-skelter slide of nutrients. This not only allows for more plants as it uses height rather than space, but it also keeps everything in one tidy, easier to manage bundle.

Essentially Nutrient Film Technique can seem a little intimidating at first, but once the initial set up is over the plants need very little watching. As long as there are no blockages or power outages this system will provide healthy, high yielding plants. It is possible to create our own DIY system at a very low cost. However, for those who have more money than spare time it is also possible to purchase premade systems. There are a number of fantastic setups available for purchase and immediately ready to use. As always it is a good idea to do plenty of research before buying a premade system. DIY systems are made specifically to growers needs whereas premade are not.

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