NFT Farming in India
Today, we discuss the topic of NFT farming in India and the advantages and disadvantages of NFT farming.
Nutrient film technique (NFT)
What is an NFT system? The N.F.T. system means the Nutrient Film Technique. It is one of the quite popular hydroponic technique. However N.F.T. systems are best suited for, and most usually used for growing smaller quick growing plants like different types of lettuce. Along with growing lettuce, some commercial growers grow different types of herbs and baby greens using N.F.T. systems.
The Nutrient film technique is a common hydroponic growing technique that has been adapted to Aquaponics. The method is favored for its easy setup and ease of use with many popular garden plants, but as with any system, there are some issues growers may encounter. The structure operates by providing a slow, steady stream of nutrient-rich water to the plant roots. The water is circulated using a mixture of pumping and gravity draining.
Best plants suitable for the NFT system or NFT farming:
What can you grow in an NFT system? NFT channels are mainly used to grow leafy green plants with a short growth period. Bibb and leaf type lettuce are an ideal plant for such a system, but you can develop other leafy green plants such as spinach, broccoli Raab, and certain herbs.
With better planning and care, any plant can be successful in a Nutrient film aquaponic system. NFTs offers a lot of advantages that effect on fast growth and plentiful yields. NFT systems are best suitable for climbers and shooters such as Cucumbers, Bell peppers, and Tomatoes, etc. They can be used for leafy vegetables such as Lettuce, Broccoli, Basil, Palak, and, Chillies, etc.
Some of the best plants for the aquaponic system include:
Romaine lettuce, Bibb lettuce, Kale, Iceberg lettuce, Swiss chard, Basil, Mint, Sage, Parsley, Oregano, Mustard greens, Bok Choi, Nasturtiums, and Pansies.
Some plants that are possible to grow with extra care using a Nutrient film technique include:
Tomatoes, Peppers, Strawberries, Eggplant
Nutrient film technique principles or NFT farming principles
The principles of Nutrient film technique are explained below;
Plant roots want oxygen in order to respire, that is, to make use of the energy input from photosynthesis. In the method of respiration, plant cells take in oxygen and release carbon dioxide. If plant roots cannot respire (often because they are waterlogged with water that has run out of dissolved oxygen), they will die.
The thing that is unique about Nutrient film technique is the fundamental requirement that the plant roots are in a flowing thin film of nutrient solution. The impact of the thin film is twofold. Initially, some of the roots in the channel will be directly in contact with the air. And then, dissolved oxygen in the water is taken up by the submerged plant roots, this oxygen can be replaced by absorption through the large surface area of the thin water film.
A well designed Nutrient film technique system will never have a problem with a lack of oxygen in the root zone. Bad design will eventually lead to plants dying from lack of oxygen, often resulting in the entire loss of the crop. By its nature, a basic principle of the Nutrient film technique is that it is a ‘closed’ recirculating system.
Build a Nutrient film technique for NFT farming:
How does the NFT system work? Nutrient film technique systems have a constant flow of nutrient solution so no timer required for the submersible pump. The nutrient solution is pumped into the growing tray generally a tube and flows over the roots of the plants, and then drains back into the reservoir.
There is generally no growing medium used other than air, which saves the expense of replacing the growing medium after every crop. Normally the plant is maintained in a small plastic basket with the roots dangling into the nutrient solution. Nutrient film technique systems are very susceptible to power outages and pump failures. The roots dry out quickly when the flow of nutrient solution is interrupted.
What do you need to build an N.F.T. system?
- Container to hold the nutrient solution or a reservoir
- A submersible fountain or pond pump
- Tubing to distribute water from the pump to the Nutrient film technique growing tubes
- Growing tubes for the plants to grow in (also called a gully or channel)
- Starter cubes, or small baskets and growing media to create seedlings in
- Return system (tubing, channels) to guide the used nutrient solution back to the reservoir
How a hydroponic Nutrient film technique system operates is fairly simple. The nutrient solution is pumped up from the reservoir, generally to a manifold that connects the larger tubing to a number of smaller ones. Each one of these smaller tubes runs nutrient solution to one side of each one of the growing channels or gullies with the plants in it. A thin layer or film of the nutrient solution flows through each of the channel’s with the plants in it to the other side, passing by every plant and wetting the roots at the bottom of the channel as it does. The nutrient solution flows from one side to the other side because the channel is sloped slightly so the water flows downhill.
The plants in the growing tubes (channel/gully) are normally suspended above the water by placing seedlings started in starter cubes or small one inch baskets of growing media into small holes in the top of the tube. The roots of the seedlings hang down to the bottom of the tube or channel where they get nutrients from the shallow film of nutrient solution flowing by. The excess nutrient solution flowing out of the low end of each of the channels drains into another channel and guided back to the reservoir where it is recirculated through the system again.
While the nutrient solution flowing through the channels is very shallow, the whole plant root mass remains moist from the roots being able to wick up moisture on the outside of the roots, as well as through humidity that’s kept within the tube or channel. The roots that are suspended between the base of the plant and the water level in the channel not have moisture to access, but are able to get plenty oxygen from the air surrounding them within the tube or channel as well.
Commercial growers typically use mostly made channels for N.F.T. systems that have flat bottoms with grooves running lengthwise along the tube or channel. These grooves allow water to flow underneath the root mass and help maintain it from pooling or damming up.
Nutrient film technique system flow rate and channel slope:
The recommended slope for a Nutrient film technique system is typically a 1:30 to 1:40 ratio. That is, for every 30 to 40 inches of horizontal length, one inch of drop or slope is recommended. We recommend when designing Nutrient film technique systems, you design it so you can adjust the slope while the plants are still growing. That’s because as the root systems get bigger, they can cause it to pool and dam up the water flow. If it’s adjustable you can tilt it more to compensate if required. Also, when building N.F.T. systems try and keep the channels or gully’s as true as possible. If they sag in spots, water will pool up in those areas.
The recommended flow rate for a Nutrient film technique system is typically between 1/4 gallon to 1/2 gallon per minute (1 to 2 liter’s) for each grows tube (channel/gully). Or between 15 to 30 gallons per hour (60 to 120 liter’s). While the plants are just seedlings the recommended flow rate can be cut in half, and then increased as the plants get bigger. Flow rates higher or lower than these have sometimes been associated with nutrient deficiencies. Also, nutrient deficiencies have sometimes been seen when growing tubes or channels are longer than 30 to 40 feet (10 to 15 meters). However, it’s been shown that having a second nutrient feed line halfway down the growing tube or channels eliminates that issue.
Maximum yield explains the Nutrient film technique (NFT)
The NFT system is similar to the ebb and flow system in that it utilizes a pump to move nutrients in a continuous, constant flow. The difference with Nutrient film technique is that the solution flows directly over the plant roots.
The Nutrient film technique uses shallow tubes that are slightly angled so that the pump moves the nutrient solution to the higher portion of the structure. The nutrient solution slowly moves by gravity to the lower portion. A tube system with holes bored for the plants is used instead of trays, mostly because this system is easier to angle for proper flow over the roots.
Most horticulturalists plants directly through the holes, but it is okay to use net pots, and several horticulturalists use no planting medium (e.g., potting soil) with the NFT. The roots fall during the net directly into the nutrient solution. The nutrient solution does not totally soak the roots. The film ensures that the whole root is not submerged so the upper part of the roots remains dry.
Because it contains moving parts, Nutrient film technique is considered an active system. Passive systems are those without moving parts such as wick systems, which are the simplest hydroponic structure and use a cotton wick to move the water. When using the nutrient film technique, it is very important to not try to grow heavy plants that require a lot of support because the roots are not in a medium that can maintain the weight of a heavy plant. It is essential to use a self-standing trellis to support plants with heavy fruits such as tomatoes.
Advantages of Nutrient film technique:
Some of the advantages of the Nutrient film technique are given below;
- Very easy to inspect roots for a sign of disease, feed adequacy, etc. due to the absence of a medium.
- Low water and nutrient consumption.
- Environmentally friendly and minimize the risk of contaminating localized groundwater.
- Unlike media based systems, avoid problems related to matters such as supply, disposal, and cost.
- Comparatively easy to disinfect roots and hardware in comparison with other system types.
- Plant roots can keep a uniform pH and conductivity thanks to regular feeding (and associated flushing) that prevents localized salt build-up.
- Easy to build and maintain.
- Very easily adaptable to different spaces and plant requirements.
- Can be built relatively inexpensively.
- No need for growing medium.
- Reduced need for aeration of nutrient solution in the reservoir, due to the constant circulation
- No fussing with timers or watering cycles.
Disadvantages of Nutrient film technique:
Some of the disadvantages of the Nutrient film technique are given below;
- If the flow of nutrient solution stops, the roots will dry out and become stressed quickly.
- The roots in the channels can become blocked by roots of vigorous-growing plants.
- Pump failure can cause the death of crops in a few hours, particularly in hot weather.
- Not suitable to grow plants with large tap-root systems like carrots.
- Compared to run-to-waste systems, saline water is not the best option for the NFT, because the salinity of the recirculating water will gradually decrease.
That’s all folks about NFT farming and its principles.
Read: Types of Greenhouse in India.