Everyone dreams of having a beautiful green space in their home. However, what could be better than a garden you can both use and enjoy?
Due to its simple design, the nutrient film technique (or NFT system) is popular with hydroponic growers engaged in soilless culture. Different types of lettuce are often grown using nutrient film technology. Commercial growers utilize this method to grow herbs, strawberries, and baby greens in addition to lettuce. The components of this hydroponic system are the same as Ebb and Flow, but the configuration is different. Let’s explore this technique further.
What is Nutrient Film Technique?
A nutrient film technique system can be designed in several ways; however, they all rely on a shallow nutrient solution pouring through the tubing. When the bare roots of the plants come into contact with the water, they will absorb the nutrients from the solutions.
One thing that makes the NFT system similar to the Ebb and Flow technique is that both rely on pumps to deliver nutrients to plants. In contrast to the ebb and flow mechanics of an EFT system, the NFT system operates continuously.
The Wicking Method and the Kratky Method are passive methods, less complex to build and easier to run. However, they don’t provide optimal conditions for plants to grow the way the NFT system does (it requires moving parts to function).
How Does Nutrient Film Technique Work?
A nutrient film technique system (NFT) consists of the following:
- A channel for growing plants
- A net pot to contain seedlings and grow media
- A pump for distributing the nutrient solution
- A reservoir to hold the nutrient solution
- A way to return the nutrient solution to the reservoir (channel, tubing)
- NFT growing tubes, which distribute water from the nutrient pump to the plants
There are two main components in the NFT system: the grow tray (or channel) and the reservoir.
- A grow tray is used to hold your plants and nutrient solution in net pots containing your growing medium (perlite, coconut fiber, and Rockwool). Since the roots of NFT systems receive enough nutrients, oxygen, and moisture by themselves, most growers do not use growing media.
- A dense mat of plant roots grows inside the channel. The trellis system supports the top foliage.
The NFT system utilizes a pump to deliver nutrient water to a grow tray and a drainage system to reuse unused solutions.
What is the process? Grow trays are angled to allow water flow to the nutrient return pipe (supported by a rack or bench). Flowing out of this pipe, excess nutrient solution will be channeled through another opening and recirculated once more. They absorb nutrients from the shallow film of nutrient solution on the bottom of the channel where their roots hang down.
Watering the plants but not completely soak them with nutrient solution because the thin film covers them. In addition to being thin, this also allows the upper roots to remain dry, receiving oxygen from the air.
The Best Plants To Grow
Plants that can be harvested in a short time, like different types of lettuce, are best suited to the NFT system, such as lightweight, fast-growing plants. Perennial plants such as strawberries have also been grown commercially with great success.
Adding a self-standing trellis system to the garden is best to support heavy plants like tomatoes and squash. Larger plants that require much support cannot be planted in the NFT since the roots are not in an environment that can support them.
Tools You’ll Need
An NFT system consists of two main components:
Instead of flat trays, growers use downward-facing tubes or channels to allow nutrients to pass through the root systems. A grow tray set on an angle can also be set up using tubes or channels.
These channels are usually created using water-tight materials, such as PVC pipes, plastic film, or round tubes. Several holes are cut out of the PVC pipe to attach the net pots and seedlings. Hydroponic hobbyists can easily acquire these materials because they are relatively inexpensive.
However, the PVC film will not evenly coat the roots if it is used as the material. As the roots near the middle of the solution reach greater depths, the roots near the edge will only reach shallow depths. You can solve this problem by using flat-bottomed channels.
Planting seedlings can be done in two ways.
- You can place seedlings directly into the PVC channel or pipe.
- For greater stability, place seeds in net pots and place the pots in the holes.
Using the NFT system, most growers do not use media. If you plan to use net pots, make sure not to put too much in the bottom for roots still deep enough to fall through. The plants’ roots should be checked and trimmed frequently regardless of the seedlings’ method to prevent clogs caused by long roots.
A grow tray’s length is another important component.
The concentration of nutrient solutions and the oxygen level will decrease as nutrient solutions flow over the roots. You can eliminate this problem by using “short-run” trays instead of long ones. By having “short-run” trays for the end of the line, the plants will receive nutrients identical to those in the beginning.
In addition to checking PH and nutrient levels, you can avoid this problem by using “long-run” trays. You should switch to a short-run system if you notice the plants near the end of the line grow much slower than the ones near the beginning.
A nutrient pump and a nutrient return pipe connect the reservoir, and the grow tray on either side. The reservoir is equipped with an air stone connected to an air pump outside for oxygenating the water.
Since the NFT system is a recirculating one, the reservoir contains the nutrient solution. Based on how many plants you wish to grow, you need to choose the right reservoir size. You need a reservoir with a minimum capacity of 5 gallons to grow 40-50 plants.
You will need to add a gallon of capacity for each additional 20-25 lettuce-sized plant. To avoid being short of volume, it is better to have a little more than you need.
Other hydroponic systems use automatic timers to control the water pump, but the NFT system does not. As a result, the water pump runs constantly. If a power outage, shortage, or other problem can cause a problem, it’s always recommended to check the pump and have a backup ready.
Advantages and Disadvantages of NFT
- Because there is no medium, it is easy to check for signs of disease, feed sufficiency, etc.
- Less likely to face problems like supply, disposal, and price
- Less likely to pollute localized groundwater
- Low water consumption and nutrient consumption
- Regular feeding (and water flushing) keeps the roots uniformly PH and conductivity
- Roots and hardware are relatively easy to disinfect compared to other types of systems
- Compared to run-to-waste systems, recirculating saline water is not the best option because it steadily degrades the salinity of the water.
- During hot weather, a pump failure can severely damage crops.
- If nutrient solutions stop flowing, roots will quickly dry out and become stressed.
- Plants with large tap-roots like carrots cannot be grown efficiently.
- Roots of vigorously growing plants tend to block the channels.
- With a newly planted system, the channels are more likely to heat up than the root zone if you aggregated the soil or thick Rockwool. Nonetheless, the constant flow of nutrients does cool the surrounding area.
NFT is a highly intuitive and easy-to-use system. The best plants to grow are those you can harvest quickly. In addition to growing various leaves, bibb, and Cos types (Romaine) lettuce, leafy greens, kale, and some oriental vegetables, you can also grow herbs and flowers in this system.
With the NFT system, you can also plant a few edible flowers, such as nasturtiums and pansies, to improve salads and food presentation. For quick results, you can use this system and plant new seeds for future harvests. Home hobbyists can now fulfill their dream of having their own green space and a continuous supply of fruits and vegetables.