Hydroponic Growing Techniques




NFT: A Beginner's Quick Start Guide

Want to learn how to grow using NFT (Nutrient FIlm Technique)? Here we give you a great leg-up and help you to avoid the common pitfalls. to help you get the most out of this exciting and high-yielding growing technique.

NFT (Nutrient Film Technique) is one of the most popular hydroponic growing styles among European hobbyists. The compact, self-contained nature of the systems has proven to be a particular hit with British growers-and we're not just talking lettuce. Heavy fruiting plants, such as cucumber, tomato, and peppers, are the mainstay of hobbyist NFT growers-all the plants need is proper support.

NFT Gro-Tank Recirculating Hydroponics SystemOver in America it's a different story. Sure, commercial growers know all about NFT. But if you haven't even heard of this technique-don't worry. We're going to take you through it right from the top!

First, some good news. NFT hydroponics systems are inexpensive, easy to set up and, once you get growing, there's almost no growth media required. Furthermore, there's no need to dial in complex irrigation schedules as most NFT growers run the pumps 24/7 to create a steady film of nutrient solution for the plants' roots to bathe in.

If you're considering giving hydroponics a go-we couldn't recommend NFT highly enough. First off, the purists will tell you, NFT is a true hydroponic growing method-giving you total control over a hyper-oxygenated, thriving root zone. A great first step is to invest in an NFT Gro-Tank if you're planning to grow heavy fruiting annual plants, or NFT gulleys if you're planning to grow leafy green crops.

What's So Cool About NFT?

Young cucumber plants in an NFT Gro-Tank
At first glance NFT might not seem that different to other hydroponic growing methods you may have explored. Nutrients are added to water just like any other hydroponics system and this solution sits in a tank. Plants sit on a grow tray above the tank and the nutrient solution is pumped up to the tray. Now, up to this point you might be thinking that all this sounds like an ebb and flow system-but here's where NFT is different: The tray that receives the nutrient solution is positioned so that it lies on a slight gradient. The nutrient solution is pumped up to the 'high end' so that it flows along the length of the tray to the slightly lower end, creating a constant, flowing film of nutrient solution over the roots dangling from the grow tray above. Any nutrient solution that is not up taken up by the roots simply flows back through a hole into the tank where it is re-circulated.

How Can Plants Grow without Growing Media?

Roots beneath the Correx cover in an NFT Gro-Tank

As we just stated, your plants' roots are constantly bathed in an oxygen-rich nutrient solution-this thin 'film' is about 0.03 to 0.1 inches deep. Not only do roots enjoy the oxygen-rich nutrient solution but, because the film is so thin, they enjoy plenty of direct access to air too. This is a key feature of NFT that's worth really highlighting. There are always some parts of the root zone that have more access to oxygen than others - simply because they are higher up: these parts of the root zone help to supply lower parts with all the oxygen they require. This is basic plant physiology in action-and NFT growers exploit it to their advantage. When plants have access to all this water, nutrient and oxygen simultaneously the growth rates can be staggering.

Spreader mat is used to promote an even flow of nutrient solution across the entire surface of the grow trayMany NFT systems use a thin layer of capillary matting called "spreader mat" which helps to spread the flow of the nutrient solution evenly over the entire surface of the grow tray. The root zone is protected from light with a piece of Correx (a cross between cardboard and plastic.) Small holes are cut into the Correx, just big enough for the base of the plants to fit through. This also helps to prevent algae growth in the root zone or nutrient solution.

Gro-Tanks vs. Gullies

NFT Gully System by American Hydroponics

NFT Gro-Tanks can accommodate a far wider root system than the NFT 'gullies' you may have seen on commercial hydroponic farms (commonly used to grow basil and other leafy greens) making them ideal for plants that produce abundant root systems such as tomatoes.

Go With The Flow

NFT Gro-Tanks often come supplied as a complete kit for hobbyists - including the right sized pump. Solution flow is generally unimportant but should normally be between 1 to 3 pints (400 ml and 1500ml) per min. Channels should be sufficiently sloped, normally not less than 1:50 but may be much steeper if set-up allows, so that there is no "pooling" in the channels.

About to plant into an NFT Gro-Tank system

Plant Stability

Heavy, fruit-bearing plants like cucumbers and tomatoes may need some support, but not as much as you might think! The plants form such a thick mat of roots underneath the Correx that they do a pretty good job of supporting themselves. Of course, no matter what your growing style, some of the more top-heavy varieties will always benefit from some net supports-especially when you are driving them to their limits!

Propagation

NFT growers start their seedlings and cuttings off in the regular way, perhaps propagating in rockwool cubes or another inert media (e.g. net pot with clay balls.) Aeroponic cloning machines can also be used. Just as with any other hydroponics system, it's really important to make sure that your seedlings or cuttings have a sufficiently developed root zone before transplanting them into an NFT grow tank. Don't just wait for one or two roots to poke out. Aim for a mass of roots first! A great tip is to use an air-pruning tray to generate a compact, dense root zone that's bursting to break free!

Why Do Plants Go So Crazy in NFT?

Have you ever visited one of those trendy (well, a little passé now!) sushi restaurants with dishes circulating round on a little conveyor belt?

Imagine if you spent all day, every day, sat by that conveyor belt? Feeling a little peckish? Eat some gyoza. Yum. Room for a little more. Tuna sashimi. Thank you very much. Picture yourself constantly 'grazing' on a constant supply of nibbles.

NFT plants feed constantly - so watch out, they can get fat real quick!

This is not unlike the world a plant growing in an NFT system enjoys with its constant access to a highly-oxygenated nutrient solution, flowing over its roots.

You, like your NFT plants, can take what they want, when they want it, rather than having to wait for their next feed. As a result, you and your plants are going to end up very happy and heavy!

Planting out and Irrigation

Look for prolific root development like this before transplanting into an NFT system.

First, mark your planting sites with a marker on the Correx sheet. Do not position any plant too close to the pump. Make the holes just big enough. The aim of the game is to allow your cuttings or seedling access to the nutrient film without letting light in through gaps. Lay a single layer of spreader mat over the grow tray. Run your pump 24/7, day and night. There's no need to work out irrigation cycles and frequencies. Your plants will simply absorb as much or as little nutrient as they require. This is perhaps one of the most appealing aspects of NFT. You should be able to see obvious root activity within 24 hours of planting out. Root axes grow into the nutrient film. Fine root hairs will also grow around the propagation media. 

Roots beneath the Correx cover in an NFT Gro-Tank

One of the best aspects of NFT growing is the ability to peer at the huge mat of roots that quickly develops underneath the Correx cover. It's easy to assess the health of your plants - just look for a thick mat of white roots! Watch that the roots don't get carried away and grow into the pump. (Unlikely, but it does happen.) Clean-up in between harvests is a lot less hassle than with media-based growing methods too, mainly because there is so little media to deal with. This makes NFT Gro-Tanks a great choice for the hobby grower who doesn't want to endure the regular hassle, expense (and back ache!) of carrying endless bags of soil, coco or clay pebbles.

Plants grown in NFT Gro-Tanks can quickly fill a greenhouse.