Growing Tips

NFT Hydroponics – A Beginners Guide

nft growing system

What Is NFT Hydroponics?

NFT stands for nutrient film technique and it is a method of growing plants that does not require soil. NFT is a versatile hydroponics system in which a pump is used to deliver fertilized water continuously. The solution that delivers water nutrients and oxygen to your plants is designed to flow over the roots in a thin film, hence the name; nutrient film technique.

The constant stream of nutrients flows over the bottom part of the roots while the upper part of the plant is left open to the ideal environment created inside the growing chamber, ensuring that the plants receive the optimal amount of oxygen.

Plenty of oxygen is needed for plants to thrive. This is one of the key components of hydroponics. Plants require carbon dioxide for photosynthesis and oxygen to absorb nutrients. when the roots of plants have an increased access to oxygen the plant thrives.

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How does NFT Work?

The main difference between Nutrient Film Technique hydroponics and ebb and flow hydroponics is the configuration. In NFT hydroponics, a tube like channel holds the roots. It is angled so that the nutrient solution can easily flow through it. There are usually several growing channels in one NFT hydroponic system.

There are holes in the top of the growing channel for the plants. The roots can stay in darkness while accessing the flowing nutrient solution while the tops of the plants poke out of the holes above accessing the light they need. NFT hydroponics eliminates the need for soil or potting mix, the only extra thing growers will need are net pots to provide extra support for their plants.

NFT hydroponics utilizes a pump to deliver fertilized water from the high end of the growing channel all the way to the bottom end of the channel where it is returned to the reservoir at the top. It is a circuitous system allowing the nutrient solution to be recycled so less water and nutrients need to be used.

Benefits of NFT:

The advantages of using nutrient film technique hydroponics over other hydroponic systems centre around its functionality and simplicity. The following list highlights some of its greatest benefits:

  • NFT Hydroponics are not complicated to build and simple to run
  • Can be changed with little problem to suit different spaces or plants
  • Does not cost a lot to build
  • No need for soil
  • The flow of the nutrient solution is constant which eliminates the need for aeration
  • No need for timers because the water flows continuously
  • The fertilized water is recycled meaning less water needs to be used

Downsides to NFT:

There are a few drawbacks to using NFT hydroponics. The most obvious is that it relies on an electrical pump running day and night. If there is a disruption to your electricity for any reason and the pump stops for any length of time the roots of your plants will suffer and the plants could suffer irreparable damage.

The second drawback to nutrient film technique hydroponics is that it is not effective for fruit-bearing plants or plants with large root systems.

NFT hydroponics works well for small, quick-growing plants such as lettuce, herbs and leafy greens. Plants that grow large roots quickly are likely to fail in this system because the extensive root system will fill the growing channel and stop the flow of fertilized water.

Growing fruit-bearing plants will be difficult using NFT hydroponics for a couple of reasons. First, it is better if fruiting and flowering plants are allowed to dry out between waterings which is obviously not possible using NFT hydroponics as the nutrient solution flows continuously. Second, fruiting plants need a lot of extra nutrients when the plant is in a fruiting stage. The recirculating system of fertilized water would have to be very closely monitored to ensure the plants are getting what they need.

Beginners Tips to NFT

18°C & 20°C Nutrient Solution

Use a nutrient thermometer to ensure that your nutrient solution remains constant at the perfect temperature. The ideal temperature will be between 18C- 20C. Use a heater and chiller to maintain this temperature.

Constant Feed Pump

Keep your nutrient solution pump running 24/7. The point of the pump is to keep the roots of your plants constantly wet. If it is turned off the roots will quickly dry out causing all kinds of problems.

Dried out roots will result in cell damage, a dead root mass and wilted plants. Simply turning your pump back on will not solve your problem as your dead root material will become flooded with the nutrient solution which will cause root diseases.

There are times you will want your plants to receive less water, such as when they are newly transplanted. If there is a situation in which you want your roots to receive less water do not turn off the pump completely, just turn it down so the water flow is very light. You can slowly turn the water up as you need it.

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Roots Must Live in Darkness

It is important that the roots remain in darkness, light can cause the roots of your plants to grow algae. The algae will warm up the roots too much and compete with the roots for oxygen. NFT hydroponics systems come with a Correx cover to prevent this from happening.

NFT is used for Established Plants

Very new and tiny plants will not be able to thrive in your NFT hydroponics system. Ensure the roots are mature enough to deal with a constant stream of water. If the roots are immature the rockwool blocks soak up excess water and end up saturating the roots. This can kill your plants.

To ensure the roots of your plants are developed enough to handle your NFT system, start by establishing the plants in 3 – 4″ Grodan Rockwool Transplanting Cubes. Once you see roots poking through the bottom of the rockwool blocks you will know it is time to introduce them to your NFT system. Your plants will be fine because the roots that emerged from the cube encouraged a big healthy set of roots to develop inside the cube.

Line up Cubes with Water Flow

When you are setting up your NFT hydroponics system you will notice the bottom of the Grodan cubes have grooves etched into them. These grooves are meant to help with the water flow. Line them up so the water can flow through the grooves, allowing the roots to grow.  Make sure that you line them up with the flow of water.

When Aerating a Tank:

The pump system in NFT hydroponics ensures that your nutrient solution is already aerated. There are a couple of things to consider if you are aerating your tank as well.

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1. It Must be an Appropriate Solution for Aeration

There are some plant nutrient mixtures that are not meant to be aerated. Make sure you check before aerating yours.

Organic ingredients such as seaweed or molasses are not meant to be aerated and they will become oxygenated if you aerate.

2. Reduce Strength

Remember that extra oxygen will increase your plants nutrient uptake. If you are aerating, you also need to lower the strength of your nutrient solution so that your plants don’t get overfed.

The precise strength of the nutrient feed may change with the type of plants you are growing, your environment as well as how hard your water is.

With the use of filtered water, your nutrient feed strength should be about 12 – 14 CF (1.2 – 1.4 EC).

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Maintain Water Flow with Single Mat Layers

You only need one layer of spreader mat. Spreader mats are used so that your water is even across all channels.

If you have more than one layer the plants will not grow as well because the water flow will be slowed.

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