Ultimate Comprehensive Guide to the Nutrient Film Technique in Aquaponics
The Nutrient Film Technique is one of three main types of aquaponics methods, each type comes with certain requirements and offers a numerous pros and cons. The three main aquaponics techniques are:
- Media Based Technique
- Deep Water Culture (DWC) a.k.a. Floating Raft Method
- Nutrient Film Technique (NFT)
In this article we’ll take a look at the Nutrient Film Technique in Aquaponics, what it is, how it works, and why you might want to select this method for your own aquaponics system.
Table of Contents
What is the Nutrient Film Technique in Aquaponics?
The Nutrient Film Technique (NFT) is an aquaponic growing technique borrowed from the hydroponic growing method. The term refers to the way in which the plants are feed, via a thin film of nutrient-rich water that is consistently passed through the roots of the plant.
In addition to the hydroponics side of the system, aquaponics couples aquaculture, the raising of fish, together with a process known as nitrification, which converts fish waste into food for the plants. This creates a closed loop system, in which each component supports the next, and this controlled climate allows growers to optimize plant health and yield.
NFT aquaponics utilize water and nutrients in an extremely efficient manner thanks to the small volume of water required to deliver nutrients directly to the plants roots, after which the water is filtered and then recycled back into the system. This method is known to enhance growth rate of the plants, promote the overall health of the plants, and purify the aquatic component of the system to support healthy fish.
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How Nutrient Film Technique (NFT) Works
The NFT method works by pumping water from the mineralization tank, where the biofilter and solid separator are housed. Once mineralization has sufficiently filtered the water, it is moved into the fish tank.
From here, you will be required to feed the fish the same as you would when keeping an aquarium. The fish will produce ammonia-rich waste that is toxic to both fish and plants if left unprocessed.
This is where the nitrification process then becomes important. Carried out by beneficial bacteria from the Nitrosomonadaceae family, these microorganisms colonize in the biofilter, and other surfaces of the system where they can convert the ammonia into nitrites and then nitrates, which the plants can use to feed on.
Water is then pumped to the plants, which are commonly placed in net pots that sit in channels made from PVC piping. These channels are often setup on a slight angle to aid the flow of water.
Once the nutrient-rich water has passed through the channels and fed the plants, it is then moved to back to the mineralization tank, where all filtration takes place to repeat the cycle again.
Advantages and Disadvantages of NFT
Each aquaponics technique has its own pros and cons. Deciding which method is most suitable for you will likely come down how these factors fit your specific situation, and what you’d like to produce in your system.
Advantages of NFT Aquaponics
Water Conservation: Due to the low volume of water that is recycled in the system, the used of water is extremely efficient.
Efficient Nutrient Delivery: The way in which the water is delivered directly to the plants roots is also highly efficient.
Oxygenation: The configuration of the system naturally lends itself to preventing water logging, which in turn promotes healthy plants.
Scalability: In addition to the excellent efficiency, NFT systems are also easily scalable, which makes them ideal for both home and commercial operations.
Easy DIY: The design of NFT systems can be easily constructed from off-the-shelf components with very little work for the amount of customization possible. Not only does this make it straightforward to build your own, it’s also inexpensive. Learn how to build your own NFT system with our DIY article here.
Space-Efficient: As noted, NFT system can also be set up as vertical farming systems, which also makes them great for small spaces and home setups.
Vertical Farming: In addition, vertical farming comes with it’s own advantages, these include:
- Even More Space Efficient
- Increased Plant Density
- Better Air Circulation
- Aesthetics
- Not sure what vertical farming is in aquaponics? Click here to find out!
Disadvantages of NFT Aquaponics
Root Blockage: Although the setup can promote oxygenation in the system, it can also be detrimental if the plants roots grow too big for the given space.
Temp Fluctuations: The thin film of water utilized to deliver nutrients is also more susceptible to temperature changes since the volume is much lower.
Catastrophic Failure: In situations where the water pump breaks, the system will not survive for very long. This is why quality is important, because if your pump breaks and you’re not around to immediately rectify the issue, it’s highly likely that your plants will die too.
Limited Plant Options: Although the NFT method is great for leafy greens and smaller vegetables and flowers, the lack of support for plants means the larger varieties are generally unsuitable.
Components of Nutrient Film Technique Aquaponics System
Fish Tank
This is the aquarium of your system, and will house the fish you feed to start the process.
Water Pump
As you may expect, aquaponics systems will require some form of water pump to move water from the tank to the NFT channels, through the filtration system, and back to the fish tank.
NFT Water Channels
PVC piping is usually the go-to material here. The pipes are available either square and rounded, and typically come in 7.5 or 11cm diameter sizes. Choose the most suitable dimensions for the size of the plants you’re growing.
Be sure to space the plants adequately, this generally requires placing the places roughly a ft. apart. This distance will vary depending on the plants species.
Net Pots (optional)
Most growers find it easier to mount the plants in net pots that sit within the channels. To achieve this you can simply drill holes to fit the diameter of your net pots, you’ll then have the option to add grow media like clay pebbles or rock wool. Alternatively, it is possible to place plants directly into the pipes, if the roots systems are robust enough to support the plant.
Grow Media (optional)
In the situation where net pots are used, it’s often a good idea to add grow media to help support plant roots. This is another optional step as it’s also possible to place plants directly into the net pot without grow media. Again this depends on the strength of the roots, and whether or not they can support the plants.
Biofilter
Part of the mineralization process, the biofilter is home to the beneficial bacteria responsible for the nitrification conversion. As water passes through the filter the microorganisms feed on the ammonia waste from the fish and cover it into nitrites that the plants used to for food.
Solid Separator
Another part of the mineralization process, this setup in the filtration process removes the solids waste from the fish that the beneficial bacteria cannot take care of.
Plumbing Network
In order to connect all these components you’ll need a series of rubber hoses, PVC pipe connections and fittings. These can all be purchase from most DIY stores, and can be easily modified to fit your setup.
How to Set Up Your NFT System
Location: The location can be an important factor, especially if you live in harsher climates of the world. Try to set up somewhere gets at least 6-8 hours of light per day, alternatively you can use grow lights, and or shading to adjust the timing. Also note that you’ll need to the environment somewhere controlled, which means some locations will be more suitable indoor, whilst other can be setup outdoor. If you do chose to setup outdoor, remember that pest, birds and other animals will want to get to your produce, so you may need to take a few extra steps to protect things.
Selecting Plants: The choice of plants will largely depend upon the type of system you want to construct. NFT systems are best for smaller plants such as leafy greens and short fruiting plants.
Selecting Fish: It’s generally advised to raise hardy fish in your aquaponics system as they are more tolerant to any changes in the system, which can kill off less sturdy species. Tilapia and goldfish are great options here, however if you’re adamant on eating your fish then tilapia are often the way to go.
Preparation Cycling: As noted in almost all articles the importance of cycling your system sufficiently prior to beginning your grow is crucial. This allows the beneficial bacteria time to colonize in sufficient numbers to perform the nitrification conversion; the process, which essentially ties the whole ecosystem together.
If you’d like to find out more about the nitrification process, why it’s so important and how you can ensure it’s complete before you being growing, then check out our in-depth article on the Importance of Cycling Your Aquaponics System.
Buy or DIY
Buy: NFT systems have become popular for use in aquaponics over the recent years thanks to prevalence of the technique in hydroponics growing. These has lead many brands to develop their own, all-in-one, solutions that can simple buy purchase and installed without the need for any construction.
These systems often look a little more professional, and maybe the best choice if you’re looking for a small herb garden to sit in your kitchen, or a nice aquarium as the center piece of your living room. The downsides to these setups is the lack of customization, as well as price, which is typically a lot more than DIY setups you build yourself.
DIY: The NFT method of aquaponics allows for an extremely straightforward, professional looking DIY build. This is thanks to the PVC piping utilized to construct the channel, and other parts of the system, which is available off-the-shelf in any good DIY store. These parts come in all shapes, sizes, and fittings, allowing for almost endless possibilities when it comes to configuration.
The DIY method not only allows you to customize the components to better fit your space, it can also save you money over pre-assembled, all-in-one solutions that
How to Maintain Your NFT System
Daily Monitoring and Maintenance:In order to keep your system running optimally, there are several parameters you should check on a regular basis, some daily, others multiple times per day.
Flow Rate Check: As mentioned the flow rate is extremely important to prevent blockages and keep the nutrients flowing. Be sure to keep an eye of this as often as possible.
pH: Another factor that can quickly kill off your plants and fish. Regularly check and adjust the pH level when necessary.
Oxygen Levels: You’ll also need to monitor oxygen levels water. Both plants and fish require sufficient oxygenation so proper aeration key.
Plant Health: Plants will likely be the first things to give you any sign there’s an issue. So check them often for any signs of stress, nutrient deficiency and/or pests. The earlier you can spot this problem the better.
Fish Health: Just like the plants the fish will also show signs of stress or disease if the conditions aren’t kept right. So be sure to monitor your fish regularly for any problems, again, the sooner you can deal with any issues the better.
Pests & Disease
Preventing and combating pests and disease can often be a big problem when the system is not monitored and maintained properly. One of the leading causes of pest and disease in aquaponics stems from nutrient deficiencies, and or contaminates from the outside world.
Algae Growth: This typically occurs when too much light is allowed to enter the system. Therefore you’ll want to refrain from using opaque materials and install shading where needed.
Root Rot: Often the result of poor oxygenation, root rot can stunt growth and kill the plants. In addition to ensuring the system is adequately aerated, you can also consider adding beneficial microorganisms that combat root rot.
Pests: Pest can be a pain for any grow, there are number of options, such as neem oil or a citrus-based insecticidal oil, that you can employ in an attempt to prevent them getting to the plants. However if you’re already dealing with an infestation then you can use natural predators like aphid midges larvae, ladybugs, or lacewigs.
How to Prune Your Aquaponics Crops
Keeping your plants in check will likely require an amount of trimming and pruning. To achieve this you can follow the general rules that advise removing dead and/or damaged leaves, encourage branching, and trim to prevent overcrowding.
This will keep your plants healthy and free from disease. It will also make it easier to assess problems, and prevent/get rid of pests.
How to Harvest Your Aquaponic Crops
Each different species of plant will require a different harvest time, however you’ll know the time is right when the plant reaches maturity, fruits ripen, or flowers begin to blossom.
Harvesting promotes new growth cycle and doing so at the right time/s allows you to get the most of your NFT system.
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How to Optimizing NFT System Performance
There are a number of tips and tricks you can follow to optimize the performance of your NFT setup. Some of the most common suggestions include:
Water flow: This can be your biggest advantage, or your biggest downfall. Ensure the water always has enough room to flow through the roots, and ensure it’s kept flowing at all times. Any blockage, or stoppage from a broken pump can and will quickly kill the whole ecosystem.
Utilize Gravity: It’s always advisable to configure your NFT channels on a slight incline to bolster the flow of water. Not only will this help the water flow through the roots, using gravity will also reduce the amount of power required to pump water through the system.
Lighting: Be sure to provide enough light, and dark, for your system. This may involve installing grow lights, shading, or careful placement depending on your location in the world, as well as the plants and fish you chose to raise.
Stable Environment: It’s important to keep the water and air temperature consistent. Plants generally typically thrive temperatures between 70-75°F / 21-24°C, whereas different fish species will require varying temperature, so be sure to research this when selecting your aquaponics fish species.
Oxygenation: You’ll also need to make sure there’s enough oxygen in the water to keep the living organisms alive. To further aerate the water you can add an air pump and air stone, or install waterfalls, fountains, or cascading steps that agitate the water to produce more dissolved oxygen (DO).
Combining Techniques: The NFT method can be combined with other aquaponics techniques to further maximize produce and yield. It’s possible to couple NFT with Media Bed systems, as well as Floating Raft setups. This can allow for a wider range of plants to be grown simultaneously.
In Conclusion
No matter your situation, NTF aquaponics can be tailored to suit your needs. Versatile when it comes to space required, efficient with its use of water and nutrients, these systems are ideal for home use, and are scalable for commercial operations.
The only real downsides to this method is the small amount of time you’ll have to fix problems if anything goes wrong, as well as the limited choice of plants the system can support. However, you can get around this by combining aquaponics techniques so you can broaden your choices.
Nevertheless, the benefits certainly outweigh the very few downsides, which makes NFT aquaponics a great choice for anyone looking to get into aquaponics, as well as experts alike.
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