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Nutrient Film Technique - Everything You need to Know Before starting

Writen By
Jelena [Agricultural Engineer ]

The Nutrient Film Technique (NFT) is a hydroponic system that uses a nutrient-rich film to provide roots with a steady supply of water and nutrients. It requires less work, little space, and it is more inexpensive to set up than other hydroponic techniques.

NFT systems are ideal for starting seedlings and growing microgreens.

It is the perfect solution for the home gardener who does not have enough space on their property. Commercial farmers can use this technique to grow vegetables in greenhouses or under grows lights year-round. 

This guide will teach you how to set up your NFT, what equipment you will need, and how to troubleshoot any problems that come up as you start growing plants with this technique.

Introduction to The Nutrient Film Technique

Developed in England in the 1960s, the NFT is a method of hydroponics that utilizes a gravity flow arrangement where you grow plants by running a very shallow stream of water through the root systems exposed to air in a channel, tray, or tube. Nutrients are applied to the system's reservoir, then pumped back to the beginning of the cycle. A thick mat of roots develops on the bottom of the channel and with this provides oxygenation as well as a constant source of water for the plant as it’s partially immersed in the liquid film of nutrients. This is then re-circulated cleaning the water and saving resources in the process.

The NFT system doesn't require any medium or growing container like soilless mix and it's ideal for starting seedlings or for growing microgreens because it has such a high yield in such a small space. It requires less labor, very little space, and it's inexpensive to set up than other hydroponic techniques.

Plants can be grown much closer together than they could be in soil––sometimes as close as one inch apart––which means you can get more plants into your setup!

What is NFT?

NFT stands for nutrient film technique. This is a hydroponic technique that uses a thin layer of water, about 2-4 inches deep, to deliver nutrients and oxygen to the roots of plants. NFT systems are either manual or automated. The manual system requires you to manually lift the water-filled tray and pour it over the top of the plant's roots while in the automated system, this process is done by an irrigation pump.

NFT systems are ideal for starting seedlings and growing microgreens because they provide enough space for small plants to grow without crowding each other out. They're also perfect for commercial farmers who want to grow vegetables in greenhouses or under grow lights year-round because NFT can be set up easily in any climate without having to worry about outside conditions, like rain or heat, interfering with their production schedule.

nutrient film technique illustration
Image Credit: iStock Photos 

Advantages of using the NFT method

NFT systems are a great way to grow plants. It is inexpensive, easy to maintain, and does not take up much space. The other benefit of using an NFT system is that it is ideal for starting seedlings and growing microgreens. This technique is also a good choice if you want to grow vegetables in greenhouses, or under grow- lights year-round.

Best Plants to Grow with the NFT Technique

Some of the best plants to grow with the NFT technique are leafy vegetables like spinach and lettuce. They are easy to grow and have a short lifespan, and you will need less space for your system and don't take up as much time as other types of plants. You can get a six-ounce head of lettuce in about thirty-five days.

  • Lettuce
  • Spinach
  • Mustard Greens
  • Kale
  • Microgreens
  • Radishes
  • Small Potatoes
  • Wheatgrass

What Equipment Do You Need for This Technique?

Some basic equipment to create an NFT system include:

  • A tank or container,
  • A pump to circulate the nutrient solution,
  • Tubing to move the liquid from the tank or container to the roots of your plants.

You can also use drip emitters which help adjust nutrient levels in your system.

It is a good idea to invest in a timer so that your pump turns on and off automatically. You would not have to worry about forgetting to turn it on or off and letting your plants go without water for too long. Some people like using CO2 injectors so that their plants get more carbon dioxide, which leads to faster growth and healthier plants.

Troubleshooting Problems as You Start Growing Plants with This Technique

There are a few common problems that you might face when you start growing plants with the Nutrient Film Technique.

Excessive growth of Algae can be caused by low dissolved oxygen in the water. All you have to do is increase the frequency of your nutrient water changes or, if you have an air pump, increase the amount of time that your system runs.

If you see green growth it can be a sign of too much Nitrogen in your system. You can fix it easily by increasing the time between your nutrient water changes or adding an air stone to your system.

Some people also have trouble with their plants not getting enough light, which can lead to underdeveloped and/or pale growth. The solution for this problem is pretty simple as well. All you have to do is get a better-suited light and place it closer to the plants.

Another common problem is root rot. This happens when you're not changing enough of your nutrient solution, and your roots are constantly sitting in stagnant water. To avoid root rot, change out at least 50-80% of the nutrient solution every day. It will ensure that your roots are growing in fresh, oxygenated water.

You should also try to do this in the morning, as you're plants will be less stressed by the changes.

If your plants are brown or dying, you probably not changing your solution frequently enough. Roots need to be in oxygenated water all the time to grow properly. If your plants become yellow, the reason could be too much phosphate in your nutrient solution. You can fix this problem by increasing the time between nutrient water changes or adding some carbon to remove some of the phosphates from the water.

PH

6-8 pH is the optimal range you are shooting for. You can measure this with a pH Meter or pH testing strips. Remember that organisms that will be food for the aquaculture food chain tend to need more 'acidic conditions, so zones of different pHs are what you want. This can be accomplished with deep, shallow, still, and actively aerated areas. Finding the equilibrium for your system between those variables can take some adjusting.

The Nitrogen Cycle

Divergent from the soil nitrogen cycle, the aquatic nitrogen cycle is equally essential. Plants, fish, and microbiology rely on converting nitrogen into various molecular compositions. Oxygen intensities establish the types of nitrogen accessible much as pH does in soil. It can be smoothly handled and regulated in an aquaculture situation by adding the correct number of plants and fish densities.

Aeration

Water aeration can occur in several ways: water pumps, falling water, or alignment to the dominant wind direction. Continually have the means to aerate your water. Getting a low-oxygen detection system and automatic aeration system may be appropriate. It is always better to aerate and filter water through gravel and plants when it enters a system.

More NFT Tips n’ Tricks

Contour Dam - Set up your NFT to be fed by a Contour Dam - Ideal for flatlands (8% or less slope); it will catch all the water running downslope. Depending on placement, you can also have your NFT drain into the contour dam.

The Aquaculture Chain of Life in a Healthy System

The following are the chain of life and plant layers of an ecologically balanced system. (Powers, 2018).

  • Algae
  • Zoo Plankton
  • Crustaceans
  • Fish

If it comes to change in some of the key elements, that will result in excessive growth of some and dying of other parts of the system.

NFT, Aeroponics, Hydroponics, Aquaponics, and Aquaculture. What’s the Difference?

Hydroponics generally tends to rely on providing nutrient-rich water to the plants without soil as a medium, so the NFT along with aeroponics is a form of hydroponics. With aeroponics, the plant roots are suspended in the air and misted, whereas aquaponics combines hydroponics with aquaculture, using fish manure to fertilize the plants while the plants clean the water.

What makes the NFT system different is that each channel is slightly sloped, and a nutrient-rich film of water gently runs through the roots. You can also add fish to your reservoir creating a synthesis of aquaponics and the NFT thus utilizing the nutrients from the fish manure and saving on external inputs.

 Nft vs DWC vs Drip vs aeroponics
Source: iStock Photos 

NFT vs. Aeroponics

NFT and aeroponics are two different hydroponic systems. NFT is a system that uses a nutrient-rich film to provide the plant's roots with a steady supply of water and nutrients. Aeroponics is a system that suspends the plant in the air while spraying them with a nutrient mist.

The main difference is where the roots are. In NFT, they are in the nutritious film.

In aeroponics, they're sprayed with nutrient mist through an overhead system.

NFT can use less water than other hydroponic techniques because it doesn't need to be constantly pumped up to the plants. It also means that you will need to feed your plants more often as they are receiving their nutrients through their roots.

In aeroponics, the roots are in the air, where they receive nutrients through a misting system. 

With aeroponics, you will need to manually check pH and nutrient levels as they're being applied by hand.

This also means that if something goes wrong and your plants don't get enough nutrients or too many nutrients, it's easier to tell when this happens with NFT than it is with aeroponics.

With aeroponics, there are many different ways you can set it up. You can use a screen for the roots, or create a drip system, to recycle excessive water back to the growing bed. While this makes it more customizable and allows more control over your plants, it can also be more complicated.

NFT plants are much easier to grow and care for, which makes them so popular. They are also easier to automate and a good choice for beginners.

The main advantage of aeroponics is that it is more customizable than NFT. You can use it when you need to control the number of nutrients or pH levels, which is not possible with NFT.

However, aeroponics is still a lot simpler than NFT and gives you less control over your plants. You can get a lot more done with an automation system like NFT than you could with aeroponics.

NFT vs. DVC (Deep Water Culture)

NFT systems are a hydroponic technique most famously used by NASA to grow plants on the International Space Station. These systems are easier to maintain than other hydroponic techniques, like deep water culture (DWC), and they require less space and labor. Some of the advantages of deep water culture are that it is very efficient in terms of the use of water and nutrients, and it allows the grower to control the environment more effectively. There are also disadvantages. The system requires a pump and a reservoir, which means more equipment to maintain than an NFT system. DWC systems are also harder to clean because they require removing the plant material from the water.

One of the advantages of NFT systems is that they require less labor than other hydroponic techniques. Because there is no need for water pumps or reservoirs, there is less plumbing and less frequent maintenance involved in keeping them running smoothly. Another advantage is that these systems are also very space-efficient. Because you don't need a reservoir or other equipment outside of your grow tent/room, you can get more plants into one growing space with an NFT system than any other hydroponic technique. Also, since your growing medium stays where it belongs (in your grow tent/room), there is no need for frequent cleaning.

NFT vs. Ebb and Flow

The Nutrient Film Technique is a hydroponic system that uses a nutrient-rich film to provide the roots with a steady supply of water and nutrients. NFT is different from other hydroponic techniques because it does not use a flood and drain system.

Instead of that, this technique relies on gravity to move the nutrient film over the root zone.

The ebb and flow system is another popular hydroponic technique that uses a flood and drain process to deliver nutrients and water to roots. The downside of this design is that it requires an expensive pump. The benefit, however, is that the flooding encourages deep root systems in plants. That means they will have better overall health than those grown with NFT or using capillary action alone.

If you are growing plants indoors, you will likely use a hydroponic system with capillary action. It is because installing a flood and drain system can be expensive.

The capillary action system works by wicking water up from the reservoir to the roots. It uses gravity and capillary action. As long as you water your plant properly before exposing its roots to the air, this type of hydroponic system will work just fine.

The biggest benefit of the capillary action system is that it is relatively cheap to build and maintain. You will need to be sure that the surface of your potting media is porous enough to absorb the water by capillary action, but aside from that, you should have no problem getting this type of hydroponic system up and running.

If you plan to grow plants hydroponically in a greenhouse or outdoors, you will want to use a flood and drain system. This type of hydroponic system requires an expensive pump, but it encourages deep root systems that are strong overall.

The downside here is that greenhouse floods might compromise the structural integrity of your greenhouse. If you are planning to use this type of hydroponic system outside or in a greenhouse, you will need to make sure it can withstand flooding.

Final Words on the NFT System

This very effective technique utilizes gravity and slopes with oxygenation principles and correct water-to-nutrient ratios. If you combine this with principles of aquaponics, you can gain an advantage by having a built-in nutrient system.

One of the few disadvantages of this system is that the water flow can quickly stop if the power goes out to the pump, so the cycle is interrupted. Other than it being a little tricky to get the slope and flow rates correct, once you have all that figured out, you’re all set!

 

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WELCOME TO H&F
HI, I'M Jelena
Agricultural Engineer
I'm an engineer of agriculture with a passion for gardening. I've been experimenting with different gardening styles for the last 15 years. In spare time, I write about and blog about my garden journey and love to share my knowledge of gardening.
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