The Hydroponic Nutrient Film Technique (NFT): The Complete Guide
The hydroponic nutrient film technique is a great process for growing plants and leafy green veggies all year round without soil.
It may seem complicated at first, but this guide will walk you through:
- The process of setting up your own system from scratch
- Tips to help it run as smoothly as possible
- How to maintain a healthy system
- What it all costs to run if you’re on a budget
What is the nutrient film technique (NFT)?
The nutrient film technique is a hydroponic system that recirculates the water containing plant nutrients in a thin sheet of flowing water. The plants are grown on top of this flow, while the plant root gets exposed to the nutrient-rich stream for about 15 minutes.
How does the nutrient film technique work?
It works by continuously flowing nutrient-rich water from a tank to the plants growing on top of it. The nutrients in the water are absorbed by the roots, and then re-circulated through a series of tubes back into another reservoir for recycling.
It usually contains only about 50% recycled water, which means that there is always fresh nutrient solution being exposed to your plants’ roots.
What plants can you grow with NFT?
The only plants that can possibly survive under these conditions are ones with extremely fast growth, small root systems and short lifespans (like lettuce). There is not enough time for them to develop deep taproots or become mature before they have to be harvested again.
Two main components you will need
The two main components required for an NFT hydroponic system are the grow tray and reservoir(s).
The grow tray
This is where you will have your plants growing. The reservoir(s) – this is the tank that holds all of your nutrient solutions, and from which it flows to the grow tray continuously.
Where your nutrient solution is stored. You’ll need one or more reservoirs that can hold all of your water mixed with nutrients, so you will have to find a container big enough.
These containers should be sturdy, since they have to support about 15 lbs of weight when filled with solution, so they can’t be made of anything too flimsy.
Other materials you’ll also need
Aside from the essentials, here are the most important materials you’ll want to grab when building your NFT system.
- Net pots – These are small containers that will hold your plants, and fit into the grow tray.
- Air pump – You’ll need an air pump to provide oxygen for your water roots (which help them absorb nutrients). A good one is important because it affects how well your plants do with NFT. Make sure to buy a long enough hose so you can keep your pump outside of your reservoir.
- Air Stones – These will create bubbles that provide oxygen for your plants.
- Water Pump – You’ll need this to pump water from your reservoir(s) up into the grow tray. Make sure it’s strong enough for what you’re planning on doing since some pumps can’t handle large amounts of water at once.
- Growing medium – This is used to fill up all of the gaps in between your net pots and grow tray, so you don’t have any dry spots where roots could die off due to lack of water (which would cause nutrient deficiencies). You can use a growing medium like coco coir, perlite, or clay pellets.
- Hydroponic nutrients – These are a must to supply your plants with all the nutrients they need. Without them, there is no way for your roots to absorb the water and become healthy enough for NFT growing conditions.
- Airline Tubing – this is used to connect all the parts of your system, especially from the water tank, and back into it again. You’ll need a sufficient length for everything to fit in where you want it to go, so make sure you have enough laying around before buying them.
- NFT Channels – You may need these to be able to grow more than one plant in the same growing chamber.
The advantages of NFT
Let’s walk through the pros of the NFT hydroponics system.
- It’s recirculating, meaning there’ll be less groundwater contamination.
- Water and nutrient usage are both lower.
- It’s simple to clean the roots and set them up.
- The presence of salt in the root area is prevented by continuous flow rate.
- Expandable and modular, with many options.
- It’s simple to assess the quality and health of the roots.
- It avoids the necessity of using a lot of growing media.
The disadvantages of NFT
No system is perfect, right? That includes NFT, so let’s see what the cons are.
- A failing pump may quickly destroy an entire crop.
- Plants with large tap-root systems seem to do poorly.
- Plants that require a ton of attention don’t do well with NFT.
How much does an NFT system cost to run?
It costs roughly $400 for one NFT system.
The cost of building an NFT hydroponic grow bed is $60, the nutrient solution is about $100 per year, and you need to buy pumps that will cost around $30 each (two total).
Here are some additional costs: 50 feet of tubing ($25), air pump (~$50), air stones (~$30), growing medium (~$20 for a bag large enough to fill the grow tray), and hydroponic nutrients which are about $50 per year.
The cost of building an NFT system is rather low, so you can afford to have more than one if needed. All in all, it’s around $60 a year.
Growing Tips for the Nutrient Film Technique System
When you are first setting up your system, it’s helpful to seed the plants in another growing medium. Then transplant them into their permanent NFT home once they have developed strong roots systems.
Pro Tip: It’s also important that all of the components be sturdy enough to support at least 15 lbs when filled with nutrient solution (even more if there are heavy croppings).
Make sure the pump is strong enough to keep up with your water usage. If it can’t, you’ll end up having roots rot due to a lack of oxygen or nutrients. You may even have an algae problem if there’s too much light exposure and not enough circulation! A small-capacity would be around 200 gallons per hour.
It’s best to use an opaque tank since clear ones allow algae growth. This can be prevented by using a UV filter or covering the reservoir with black sheeting when not in use. Now that you know about NFT and how it works, give it a try!
Conclusion: Is the Nutrient Film Technique right for you?
Now that you know about the hydroponic nutrient film technique, you can decide if it’s right for your needs. Let us summarize what we’ve discussed in this blog post so far.
It’s a recirculating hydroponic system with water roots and an air pump to provide oxygen for them. It uses less water and nutrients than most other hydroponic systems.
Not only that, but it’s simple to set up, clean the roots, assess their health, and expand with more plants if desired. There are also some disadvantages like possible pump failure or algae growth in clear reservoirs that can cause problems for your crop.