Posted on

Nutrient Film Technique Tips

9 Top Nutrient Film Technique Tips To Get The Best From Your Crop

  1. Make sure that the temperature of your nutrient solution is stable. We recommend keeping the temperature at around 17-20oC for optimum nutrient uptake improved levels of dissolved oxygen.
  2. Keeping the nutrient solution pH levels between 5.8 and 6.2 is the ideal range for plants in NFT systems. Check your solution frequently, especially as your plants mature. If they creep above that level, use some pH Down to bring it back down again.
  3. Remember to refresh your nutrient solution. Every 7-10 for a nutrient solution change is ideal. If you’ve got a larger version of the Gro-Tank or Multi-Duct you might be able to go a few days longer, but to keep the solution potent, frequent changes are a must.
  4. A key tip to remember and something that catches out a few growers, especially ones new to NFT and that’s to completely remove plastic wrapping from the rockwool cubes that you might use to support your plants in an NFT system.
  5. Don’t let light damage your plant’s root. Make sure to use a correx cover to keep the light out. 
  6. Keeping your reservoir clean between grows is advised. A wipe around with a gentle detergent and then rinsed thoroughly will avoid any pathogens remaining, meaning that your next crop of plants will get a healthy start.
  7. Avoid the drip, drip, drip of water returning to your tank by making sure that your feeder mats are cut to cover the top tray and hang into the nutrient solution. 
  8. One critical element that mustn’t be ignored is that if you’re using rockwool blocks for NFT growing then you must have plenty of white roots on the outside of the block before planting out into our Gro-Tank or Multi-Duct.
  9. When starting to grow your plants use a half strength nutrient solution.  After about a week or so you can progress to a full dosage. Half strength will be enough for your fledgling plants to thrive, before they become more established and need more food.
Posted on Leave a comment

How Does Nutrient Film Technique work?

When people think of hydroponics they often think of NFT, but don’t always know what it is.

In this article we’ll explore what Nutrient Film Technique (NFT) is, how it works and why it’s known as one of the simplest growing methods around.

What is Nutrient Film Technique?

Nutrient Film Technique or NFT as it is more commonly known is where a shallow stream of nutrient solution flows, like a film over the plants roots. The nutrient solution is pumped from a vessel, like a reservoir tank over the plants’ roots, where it is recirculated through the NFT system again and again. Making it one of the most efficient hydro systems available.

How does the NFT system work?

The constant flow of nutrient solution flows over the plants’ roots so that it can feed when it needs, rather than when someone is able to water their plants. A tray or reservoir sits below a tray, which is sloped to allow the nutrient solution to easily pass over the roots of a plant and then back into the reservoir. The nutrient solution rises from the reservoir onto the tray above via a pump, which send the nutrient solution from the reservoir up onto the top tray.



Growing medium isn’t required in an NFT system, though the plants are often held in place with an inert media, like a rockwool cube, like a Grodan block. That’s not to say you can’t use other types of media in an NFT system.


A quality propagator provides the best environment for healthy seeds. An X-Stream Heat propagator allows you to control the heat and humidity to achieve a well rooted plant that you can then transplant to a hydro system.

Using Compost

One way of generating high quality plants to be put into an NFT system is to germinate seeds in a seed tray of compost. When they’re big enough you can then transplant them into a plastic pot with drainage holes. Plants are ready to be transplanted when you can remove the pot and the compost remains bound by the white roots of your transplants. 

When to Plant Out

One of the most important things to remember is that you should not transplant into an NFT system until the plant is well rooted. It’s important that there’s a lot of white roots available to take the nutrients that are circulating throughout the NFT system. If white roots aren’t on the outside they’re likely to become saturated with no access to oxygen and ultimately die-back.

Using Rockwool

Before using rockwool, like a Grodan block, it is highly recommended that you soak the rockwool overnight in water at pH 5.5. What this does is reduce alkalinity. You can then plant seeds in the rockwool cube. When doing this gently bury and cover over the seed using a blunt instrument and allow to germinate.

Cuttings Developed in Aeroponic Propagators

Bring the seeds or cuttings on as directed by your propagator instructions.

Young plants can then either be transplanted to an alternative medium, e.g. rockwool, and grown on before transplanting to your system, or grown on in the propagator until the roots reach 8 – 10cm in length and transplanted directly into your NFT system.

Raising Transplants from Cuttings

Follow the instructions for raising from seed but DO NOT use nutrients in the water until your cutting has rooted.

Before Planting Out

Add nutrients according to the manufacturer’s instructions. Check pH.

When To Plant Out

Do not plant into your NFT system until the plant is well rooted. If white roots aren’t on the outside of the growing medium when you place your plant into the NFT system the roots will become saturated with no access to oxygen and will die-back.


Maintaining pH is a key element of using and maintaining an NFT system. Follow these points below and you’ll be on your way to a great grow.

  • Check pH levels in your tank weekly
  • Decide the pH you want to maintain, between 5.8 – 6.5 is ideal
  • Test the pH of the nutrient solution in your tank using a test kit or pH pen
  • If the pH of the solution is in the correct range 5.8 – 6.5 do nothing
  • If the pH of the solution is above the correct range add phosphoric acid (pH Down)
  • If the pH is below the correct range add potassium hydroxide (pH Up)

Use the pH Down or pH Up very sparingly. Adjust pH to your chosen level over several days.

Safety First

Phosphoric acid is strongly acidic and potassium hydroxide is strongly alkaline.
Always follow the safety instructions on the container.

Top Tip

Remember a consistent temperature is key. Use a submersible heater to assist in achieving this.
So that’s what NFT (Nutrient Film Technique) is, how and when o plnt out and what growing mediums

Posted on Leave a comment


How do I add my soil-started plants to NFT Gro-Tank?

If you’ve started in soil in pots tip the plant out of the pot and place the plant directly on top the planter tray.

Check there are lots of roots on the outside of the soil which prevent soil from falling away before transplanting to NFT.

Can I add aeroponically started plants to NFT?

Yes! If you’ve started plants in an X-stream aeroponic propagator the net pots can be placed straight onto the planting tray.

Check the roots are 10cms below the clone collar before transplanting to NFT.

What timings should I use for the pump?

For the best results keep you pump going 24/7.

When running constantly ducts deliver nutrient solution in a constant slow trickle all day every, day, so plants always have access to optimum amounts of water, nutrients and oxygen. 

What temperature should I keep the reservoir at?

Maintain a consistent temperature in your NFT Gro-Tank and we recommend keeping reservoir temperature between 19oC and 21oC.  You may want to use a heater for when grow lights are off and the temperature in the grow room drops.

What plant spacings should I use?

1 square foot per plant is ideal. Don’t overcrowd the plants in your NFT system.

The plants will become much bigger than those grown in soil or coco, so you don’t need to grow as many as you have done in pots.

How many NFT options are there?

There are 6 Gro-Tank varieties that will accommodate from 1-25 plants. They’re available in sizes to fit the most common grow room sizes.

For more information check out our Gro-Tank and Multi-Duct pages.

I want to grow 3 plants, which NFT Gro-Tank should I choose?

For the best results and to provide your plants with extra space to grow, we recommend using the GT424 system.