Guide to Nutrient Film Technique Aquaponics System

One of the hydroponic techniques that has found a valuable place within aquaponics is the Nutrient Film Technique (NFT). This blog explores the Nutrient Film Technique in aquaponics and discusses its principles, components, benefits, and considerations. By the end of this article, you'll understand what the Nutrient Film Technique Aquaponics is and how NFT plays a role in modern sustainable farming practices.

What is Nutrient Film Technique in Aquaponics?

The Nutrient Film Technique (NFT) is an aquaponic growing method that involves a thin film or layer of nutrient-rich water that flows over the plant roots in a continuous stream, providing them with a consistent supply of nutrients and oxygen. In aquaponics, NFT is a powerful tool that optimizes the growth of various plants, including herbs, vegetables, and small fruits.

The NFT system aquaponics is known for efficiently using water and nutrients. It is because the NFT channels offer an effective way to harness the nutrient-rich water from the fish tank and deliver it directly to the plant roots. This method enhances the growth rate and overall health of the plants while also contributing to the purification of the aquatic environment for the fish.

How Nutrient Film Technique (NFT) Works

In the NFT aquaponics system, the water is pumped from the biofilter into the grow pipes with a small equal flow that creates a shallow stream of nutrient-rich water flowing along the bottom. The grow pipes contain holes along the top of the pipe into which the plants are placed. Upon exiting the grow pipes, the water flows back into the fish tank.

As plants consume the nutrient-rich water, they begin to develop root systems inside the grow pipes. The roots also clean and filter the water before it flows back into the fish tank. The water that enters the fish tank causes the tank to overflow through the exit pipe and back into the mechanical filter, completing the cycle.

Unlike the media based system, the Nutrient Film technique does not require a flood and drain period because the water in NFT flows consistently from the fish tank.

Advantages and Disadvantages of NFT

Key Advantages of nutrient film technique aquaponics system:

1. Efficient Nutrient Delivery: NFT systems aquaponics provide a highly efficient means of delivering nutrients directly to plant roots that promote faster growth and higher yields.
2. Water Conservation: The NFT technique conserves water by recirculating it, minimizing waste and evaporation.
3. Oxygenation: The flowing water in NFT channels oxygenates the roots, preventing waterlogging and promoting healthier root systems.
4. Space-Efficient: NFT systems are suitable for growers with limited space, making them an excellent choice for urban and indoor aquaponic setups.
5. Scalability: NFT systems can be easily scaled up or down to accommodate various plant varieties and quantities, making them adaptable to different needs and space constraints.

Disadvantages of NFT aquaponics system:

1. The roots can clog the channels: Roots dangling in the water are great for the plants' health. However, as the plants grow, bigger roots can block the channels, preventing the water from getting to the rest of the plants, which may cause nutrient deficiency for the plants.
2. Water temperature fluctuations: The water that is pumped through the channels can quickly cool down or heat. This is because the film of water running through the NFT channels is very thin and subject to temperature fluctuations.
3. Pump failure can destroy yield: If the pump fails, plants cannot have access to the water and will wilt or die rapidly. 
4. Can only grow limited plants: Leafy greens and small vegetable plants do well in an NFT system, but larger plants with large root systems are not suited for NFT.

Components of Nutrient Film Technique Aquaponics System

1.Fish Tank

A fish tank plays an essential role as they provide a place for the fish to live. So it is necessary to choose the right fish tank to ensure the success of your system.

2.Water Pump

A water pump is a vital component of any NFT aquaponics system. The water pump ensures that the water is continuously pushed throughout your aquaponics system to provide nutrients to the fish and the plants. Suppose your water pump is not reliable enough to do the job of distributing the water in the system. In that case, the consequences could be a failure in building and maintaining your aquaponics system. 

3.Filter 

In NFT systems, mechanical and biological filtration is essential because it does not have enough surface area to provide a habitat for the bacteria. This is why filters must be constructed as a physical trap to catch solid wastes and natural filters for nitrification. The biofilter is usually a tank or barrel that holds a porous medium that is heavily aerated and should be situated after the fish tank and solid filter before the water returns to the plant's channels. 

The water travels from the fish tank → solid filter → biofilter → NFT channels → fish tank.

4.Rubber Hoses, PVC Tubings, and Fittings

The hoses, tubes, and fittings help to piece everything together and prevent leaks and evaporation.

5.Clay Pebbles or Similar Grow Media

The  grow media allows the plants to stay firmly anchored and develop healthy roots. The common grow media used in aquaponics systems are clay pebbles, lava rocks and gravel.

6.Pipes

NFT uses  plastic pipes (usually PVC pipes) that are laid horizontally to grow plants. The pipes can be arranged in different patterns on walls, fences, and overhanging balconies.

• Grow Pipe Shapes and Sizes

In NFT, pipes with a square cross-section are best, but most aquaponics farmers use round pipes because it is readily available in most locations. It is advisable to choose a pipe with the optimum diameter for the types of plants grown. For larger fruiting plants, use an 11 cm diameter grow pipe, while for fast-growing leafy green and small vegetables with small root mass, use a 7.5 cm diameter grow pipe. 

• Planting in the Grow Pipes 

When planting in an NFT system, holes are drilled into the grow pipes (7-9 cm diameter), which should match the size of the net cups used. There should be at least 21 cm between the center of each plant to allow adequate plant space. The seedlings are placed in a plastic net cup and then in the grow pipe's hole.  

The net cups will provide support to the plants. Putting a space of about 8 inches between each plant is recommended to give enough room for the plants to grow. Grow media like clay pebbles or gravel can be placed around the seedlings in the net cups to balance and support the plants. For more detailed planting instructions, read "How To Start Planting In Aquaponics."

Setting Up Your NFT System

A. Location and Environment Considerations

1.Site Selection: Choosing the right location for your NFT system is crucial. It should receive adequate sunlight, typically at least 6-8 hours of direct or indirect sunlight per day, although NFT systems can also be set up indoors by using grow lights.

2. Temperature and Climate: Consider the climate in your region. NFT systems are best suited for plants that thrive in the temperature range of 70-75°F (21-24°C). In colder climates, you may need to provide additional heating or insulation.

3.Protection from Pests: Depending on your location, you may need to protect your NFT system from pests like birds, insects, and rodents. 

B.Choosing the Right Plants for NFT

Select plants that are well-suited for NFT systems. Small rotted plants like, lettuce, basil, mint, cilantro, leafy greens, and smaller fruiting plants like strawberries work particularly well. Research the specific requirements of the plants you intend to grow to ensure they are compatible with NFT.

C.Building or Purchasing NFT Channels

1.DIY vs. Purchasing: Decide whether you want to build your NFT channels from scratch or purchase pre-made ones. DIY options can save costs but require more effort and expertise. Purchased systems are convenient, but may be more expensive.

2. Materials: If building your channels, use materials like PVC or other food-grade plastic materials to ensure they are food-safe and durable. Design your channels with the correct dimensions, slope, and spacing to suit your chosen plants.

D.Preparing the Aquaponic System

1.Fish Tank: Ensure your fish tank is established and cycled before introducing plants to your NFT system. This means having the right water quality and fish species in place.

2. Beneficial Bacteria: Check that the aquaponic system has a well-established colony of beneficial bacteria to convert fish waste into plant nutrients

E. Installing the NFT Channels

1.Positioning: Install the NFT channels at the selected location, ensuring they are level and have the correct slope for water flow.

2. Secure Plants: Place the plants in grow cups or channels within the NFT channels, ensuring the roots are in contact with the flowing nutrient solution.

3. Water Pump: Set up a water pump to circulate water from the fish tank to the NFT channels. Ensure the flow rate is appropriate for your system and plants.

Maintaining Your NFT System

A.Daily Monitoring and Maintenance Tasks

Successful NFT systems in aquaponics require consistent care and attention. Daily monitoring and maintenance tasks include:

1. Flow Rate Check: Ensure the water flow in the NFT channels is consistent. Irregular flow can result in uneven nutrient distribution and poor plant growth.
2. pH: Regularly measure and adjust the pH level. This helps maintain the appropriate nutrient levels for your plants.
3. Oxygen Levels: Monitor the oxygen levels in the nutrient solution and the fish tank. Adequate oxygenation is essential for both plant roots and fish health.
4. Inspect for Clogs: Check for any blockages or obstructions in the channels or tubing and clear them promptly to maintain a smooth water flow.
5. Plant Health: Examine the plants for signs of stress,nutrient deficiencies, or pests. Early detection allows for timely intervention.

B.Preventing and Managing Common Issues

1. Algae Growth:  Algae can thrive in NFT channels. Prevent it by keeping light away from the channels or using opaque materials. Regular cleaning may also be necessary.
2. Root Rot: Proper oxygenation is crucial to prevent root rot. Ensure the roots have access to oxygen, and consider adding beneficial microorganisms to the system to combat root diseases.
3. Pests: Inspect plants for pests regularly. Remove any affected plants and consider introducing natural predators or using organic pest control methods.
4. Nutrient Imbalances: Keep a close eye on nutrient levels to avoid deficiencies or excesses. Adjust nutrient solutions as needed to maintain the proper balance.

C.Pruning and Harvesting Plants

• Pruning: Regularly trim and prune your plants to remove dead or damaged leaves, encourage branching, and maintain a healthy canopy. Pruning also prevents overcrowding, which can lead to disease and poor airflow.
• Harvesting: Harvest your crops when they reach the desired size and ripeness. Harvesting promotes new growth and ensures you get the most out of your NFT system.

Tips for Optimizing NFT System Performance

To achieve optimal plant growth and productivity in your NFT aquaponics system, consider the following tips for system performance:

1. Ensure that the flow of nutrient-rich water over the plant roots is consistent. Any interruptions or fluctuations can affect plant health and growth. Regularly clean and inspect channels to prevent blockages.
2. Maintain the correct slope in your NFT channels to ensure smooth nutrient flow. 
3. If your NFT system is indoors, provide adequate lighting using grow lights that match the specific light requirements of your plants. 
4. Maintain the right temperature for your plants and fish. Plants generally thrive in the range of 70-75°F (21-24°C), and fish have specific temperature preferences depending on the species. Use heaters or coolers as needed.
5. Ensure that the root zone in the channels is well-aerated. Consider adding air stones or diffusers to maintain oxygen levels.

NFT System Variations and Innovations

NFT systems in aquaponics have evolved over the years, leading to various adaptations and innovations. These variations offer different benefits and applications, allowing aquaponic enthusiasts to tailor their systems to their needs and constraints.

A.Vertical NFT Systems

Vertical NFT systems take advantage of limited space by growing plants vertically. Instead of horizontal channels, these systems employ stacked or tiered channels, providing several advantages:

1. Space Efficiency: Vertical NFT systems are ideal for small spaces or urban environments, as they make the most of vertical real estate.
2. Increased Plant Density: By stacking channels, you can grow more plants in a smaller footprint, maximizing your harvest.
3. Enhanced Air Circulation: The vertical setup promotes better airflow, reducing the risk of disease and improving the overall health of the plants.
4. Aesthetic Appeal: Vertical gardens can be visually appealing, making them a popular choice for home gardeners and commercial settings.

B.Combining NFT with Other Aquaponic Methods

Combining NFT with other aquaponic methods can yield innovative and highly productive setups. Some common combinations include:

• Media Beds and NFT Hybrid: This hybrid system incorporates media beds filled with growing media like expanded clay pellets or gravel alongside NFT channels. It provides the benefits of both systems, allowing for a diverse range of plant types and sizes.
• Raft and NFT Combination: Raft systems are ideal for floating plants on the water's surface. Combining these with NFT channels can provide a dual-layered approach for growing various crops efficiently.

Conclusion

Like the other aquaponics systems, Nutrient Film Technique Aquaponics Systems offer many advantages and disadvantages. It offers a sustainable and efficient approach to growing fish and plants in a closed-loop ecosystem. NFT systems in aquaponics not only empower growers to cultivate a diverse range of plants but also promote the health of the aquatic environment, making it a win-win for both plant and fish enthusiasts. As aquaponics continues to evolve, the possibilities for innovation and growth are limitless, making it an exciting and promising field for sustainable agriculture.