How to Build a Nutrient Film Technique (NFT) System in Hydroponics

To make an NFT hydroponic system, put together sloped grow channels, a reservoir, a water pump, and net cups. Add a nutrient solution and make sure there is a continuous flow over the plant roots. This water-efficient configuration delivers high yields for indoor or outdoor gardening. 

NFT is a type of hydroponic system that uses up to 90% less water than traditional soil-based gardening while enhancing plant growth. The NFT (nutrient film technique) was created by Dr. Allen Cooper in the 1960s and, since then, has changed the way we practice indoor gardening. 

With NFT hydroponic systems, shallow-rooted plants like lettuce, herbs, and microgreens, which are well nourished in the film, can be grown effortlessly. The adaptability of the NFT hydroponic system is one of its biggest advantages. They can be arranged vertically or horizontally, allowing them to be used in small apartments or large greenhouses. In addition, the nutrient film system is highly scalable, making it ideal for home gardens as well as large-scale commercial operations.

What Is The Nutrient Film Technique?

Like other hydroponic methods, NFT doesn’t require soil. Instead, it uses channels set at a slight incline through which a thin film of nutrient solution flows continuously. Only the lower portion of the roots stays submerged while the rest receives optimal oxygen.

Essential NFT system components include:

• Grow channels (usually made of PVC or specialized NFT troughs)  
• Reservoir for nutrient solution  
• Water pump for circulation  
• Net cups to hold plants  
• A collection system for the returning solution 

Channels should be positioned at a 1:100 slope for proper gravitational flow, with each channel maintaining a flow rate of 1 to 2 liters per minute. If you are a beginner, you can start at 0.5 liters per minute. 

How NFT Differs From Other Hydroponic Systems

NFTs’ key distinction lies in root exposure. While Deep Water Culture (DWC) fully submerges roots, NFT exposes most roots to air, like plants suspended in a “lake” (DWC) versus a “river” (NFT).

This reduces pest and disease risks compared to media-based growing systems and prevents nutrient salt accumulation through constant circulation.

However, NFT systems are vulnerable to pump failures. Plants can wilt within hours if water flow stops, unlike buffered systems like Ebb and Flow. 

Why NFT Is Good For Beginners

Despite potential pump issues, NFT offers several beginner-friendly advantages: 

• Easy-to-understand concept: It is simple and needs few parts.  
• Monitoring plant growth: Roots can be easily accessed for inspection, making potential problems easy to diagnose.

• Use of space: Shallow channels can be arranged vertically, providing multiple configurations that increase the growing area.  
• Low maintenance: The system is autonomous and operates consistently without the need for timers or complex cycling.  
• Eco-friendly: The closed-loop system protects groundwater from contamination while minimizing resource use.  

pH is important in hydroponics. Monitor your system and maintain pH between 5.5. When needed, adjust the hydroponic pH level accordingly. 

Essential Components You’ll Need

Setting up an efficient NFT hydroponic system has a lot to do with the selection of the correct parts. The role the part carries out is specifically the construction of the perfect plant-breathing environment.

NFT Channels And Their Types

Since they serve as the conduit of nutrition to your plants and provide protection, NFT channels are the most crucial part of your system. As a result, you must choose among several options:

Food-grade PVC pipes (3-4 inches in diameter) make excellent DIY channels for smaller setups. These readily available pipes can be easily modified with holes for net pots. The specialized NFT channels for the professional setups are manufactured from UV-resistant plastic; therefore, they are lighter and have more optimized designs than those made without UV protection.

The preferred slope of the channel lies somewhere between the ratios of 1:30 and 1:40, which is just enough to prevent pooling due to the excessive speed of the liquid flow. This light drop prevents the formation of water pools while allowing the very thin “film” of the technique to be maintained.

The channel length should be no more than 10-12 ft so that the portion at the farthest end does not lack nutrients. If your garden is larger, distributing the channels in multiple shorter sections gives you a better solution than having fewer but longer channels.

Reservoir And Water Pump Setup

Your reservoir stores and supplies the nutrient solution to the entire system. Select a food-grade container that holds at least 10 gallons for small systems, with larger setups requiring proportionally bigger reservoirs. Black or opaque containers prevent algae growth by blocking light.

The pump is your system’s heart, circulating nutrients throughout your channels. For most home NFT systems, submersible pumps rated between 250-400 gallons per hour provide sufficient flow. Position your pump inside the reservoir, ensuring it remains fully submerged.

To calculate the minimum reservoir size, multiply your total channel length by 0.5-1 gallon per foot. This ensures adequate nutrient solution volume for stable temperature and concentration levels.

Net Cups And Growing Medium

Net cups hold your plants while exposing roots to the nutrient film. These plastic containers, available in 2-inch and 3-inch diameters, feature slotted sides that allow roots to extend into the channel.

For growing medium, NFT systems require only minimal substrate since the roots primarily develop in the flowing nutrient solution. Suitable options include:

• Rockwool cubes: Excellent water retention for seedlings
• Expanded clay pellets: Lightweight with good drainage
• Coconut coir: Sustainable alternative with excellent water management properties

Nutrient Solution And Ph Meters

Proper nutrition demands a complete hydroponic nutrient formula containing all essential macro and micronutrients. Two-part solutions allow greater flexibility in adjusting nutrient ratios as plants mature.

Accurate measurement is critical for success. A reliable pH meter like Atlas Scientific’s pH Kit lets you maintain the ideal range of 5.5-6.5 for most plants. Similarly, an electrical conductivity (EC) meter helps you manage nutrient concentration, typically between 1.0-2.0 mS/cm, depending on plant type and growth stage.

Temperature affects nutrient availability, with most plants preferring solution temperatures between 65-75°F (18-24°C). To closely monitor temperature, a temperature sensor is required. 

Optional Tools: Timers, Air Pumps, And Filters

For enhanced system performance, consider these additional components:

• Digital timers control pump operation, though most NFT systems run continuously
• Air pumps and air stones oxygenate your reservoir, improving root health
• Mesh filters prevent debris from clogging channels and pumps
• Backup power systems protect against pump failures in case of power outages

First-time builders should focus on acquiring quality versions of the essential components before adding optional elements. A reliable pump and accurate monitoring tools contribute more to success than elaborate accessories.

Step-by-Step Guide to Building Your NFT System

Assembling your own NFT system hydroponics setup requires careful planning and precise execution. With each component working together, you’ll create an efficient growing environment that maximizes plant production while minimizing resource usage.

1. Plan Your Layout And Space

Begin by evaluating your available space, considering light conditions and temperature stability. For optimal growth, select a location receiving 6-8 hours of sunlight daily or plan for supplemental lighting. 

Measure your area carefully to determine the number and length of channels your space can accommodate. Sketch your design on paper first, accounting for:

• Adequate spacing between channels (typically 8-12 inches)
• Accessibility for maintenance and harvesting
• Proper height for comfortable working

2. Assemble The Support Structure

Your support structure must be sturdy enough to hold water-filled channels with mature plants. Materials like square metal tubing, PVC pipe, or sturdy wooden frames work effectively. 

When building:

1. Position the structure so the reservoir sits at the lowest point
2. Ensure the frame is level side-to-side but allows for proper channel slope
3. Reinforce joints and load points to prevent sagging over time

3. Install The Channels With Proper Slope

Channel installation requires precision for proper nutrient flow. Secure your channels to the support structure using pipe clamps or similar fasteners. The ideal slope falls between a 1:30 and 1:40 ratio, creating just enough decline for the nutrient solution to flow evenly without pooling or moving too quickly.

4. Connect The Reservoir And Pump

Position your reservoir below the lowest channel end. Install your submersible pump in the reservoir and connect it to the highest point of your first channel using flexible tubing. 

For multiple channels, create a manifold system that distributes flow evenly. Calculate the proper flow rate at 3-5 gallons per hour per channel.

5. Add Net Cups And Seedlings

Insert net cups into the pre-cut holes along your channels. For seedlings:

1. Start seeds in rockwool cubes or a similar medium
2. Wait until roots extend from the growing medium
3. Transfer to net cups, ensuring roots reach the bottom

6. Start The Nutrient Flow And Test The System

Before adding plants permanently, test your nutrient film system thoroughly:

1. Fill the reservoir with water and run the pump
2. Check for leaks at all connections
3. Verify that water flows through all channels correctly
4. Adjust the flow rate as needed

Once the system passes testing, add nutrient solution according to your chosen plants’ requirements. Monitor pH (5.5-6.5) and EC levels regularly using quality meters like Atlas Scientific’s pH meters and conductivity sensors.

Choosing The Right Plants For NFT

Selecting the right plants can make or break your NFT system hydroponics setup. Not all vegetables and herbs perform equally well in the thin film of nutrients that characterizes this growing method.

Best Leafy Greens And Herbs To Grow

The shallow water channels of nutrient film technique hydroponics create ideal conditions for plants with compact, shallow root systems. Leafy greens excel in these environments, primarily:

• Lettuce varieties: Butterhead, romaine, oakleaf, and multi-leaf lettuce thrive in NFT setups, offering quick harvests and excellent nutrient uptake.
• Other greens: Spinach, kale, mustard greens, arugula, sorrel, tatsoi, mache, and frisee perform exceptionally well, creating visually appealing mixes with different colors and textures.
• Culinary herbs: Basil, mint, cilantro, chives, and parsley flourish in NFT systems, developing lush, aromatic growth thanks to the constant flow of oxygenated nutrients.

Plants To Avoid In NFT Systems

NFT hydroponic systems have limitations regarding which plants will succeed. Essentially, avoid:

• Large fruiting plants like tomatoes and peppers without substantial support modifications
• Root vegetables that require significant depth for development
• Plants with extensive root systems that might block nutrient flow in channels

Although strawberries can work with extra support, they’re at the boundary of what NFTs can effectively grow.

Tips For Seedling Transfer And Spacing

Successful transplanting into your nutrient film system requires precise timing. Seedlings are ready for transfer once they develop enough roots to reach the nutrient solution flowing through the channel. Notably:

• Start seeds in appropriate media like rockwool cubes, foam, or compressed peat/coir
• Transfer seedlings when white roots are visibly extending from the growing medium

• Position plants so that root tips make immediate contact with the nutrient solution
• Space plants according to their mature size—generally 6-8 inches for lettuce varieties

Consequently, most NFT systems aren’t designed for direct seed starting. The thin film of water at the channel’s base cannot provide sufficient moisture for germination, necessitating separate seedling propagation.

Maintaining And Troubleshooting Your NFT Setup

Regular maintenance ensures your NFT system hydroponics setup runs smoothly and produces healthy crops year-round. A proactive approach to system care prevents many common problems before they affect your plants.

Monitoring Water Flow And Nutrient Levels

For optimal plant growth, maintain a minimum 2% slope in horizontal NFT channels, ensuring proper nutrient film flow. The flow rate should be 3-5 gallons per hour into each channel. Check these parameters twice weekly.

EC and pH measurements are vital for plant health. Most plants thrive at pH levels between 5.5 and 6.2. Monitor EC and pH at least twice weekly using quality meters. These readings indicate whether your nutrient solution needs adjustment through the addition of fertilizer solution or fresh water.

First and foremost, inspect your system daily for:

• Consistent flow across all channels
• Proper nutrient solution temperature (65-75°F ideal)
• Signs of stress in plants that might indicate system issues

Preventing Root Clogs And Algae Growth

Root clogs act like dams in your channels, disrupting water flow and nutrient distribution. To prevent this issue, select plants with appropriate root sizes for your channel dimensions and regularly clean the channels.

Algae thrive when light reaches nutrient-rich water. Consequently, use opaque materials for all system components that contain water. For persistent algae problems, hydrogen peroxide (3ml per gallon of 3% solution) effectively controls growth.

Cleaning routines should include:

1. Regular removal of plant debris
2. Channel scrubbing during crop rotations
3. Complete system sanitization twice yearly

How To Handle Pump Failures Or Leaks

Given that the NFT system is a continuous flow system, a pump failure can be a very big problem, leading to a short-circuit scenario. Think of it as an analogy where the plant is the user of energy in the system and the pump is the energy source. If the pump stops working, the energy flow to the plant is cut off, and as a result, the plant will wilt. Hence, it is advisable to carry out a risk assessment and see if your system is compatible with having a backup pump alongside a power backup.

Most times, leaks can come from unsealed connections or from root blockage of the channels. In the course of your life cycle management activities, it is very important to always be on the lookout for any potential leakage problems. Leaks may occur in pipe junctions or at the reservoir edges.

The leak can be fixed very quickly by:

• Find out where the leak is coming from
• Seal the leak in place with the sealant that is safe for water
• Wait 24 hours for the sealant to dry, and then add water again

It is important to carry out a thorough inspection of the system every week during the season. This simple habit of being proactive in preventing problems will not only keep the nature of your nutrient film technique hydroponics setup, but will even extend the productive life of your system.

Summary

The nutrient film technique is based on the very smart idea of using a thin stream of nutrient water that is continuously circulated over the plant roots. This method is more efficient than regular growing practices as it provides an ideal blend of water, nutrients, and oxygen.

Creating your own NFT hydroponic system is a great way to enter the world of soilless growing. NFT systems may sound technical, but they turn out to be very forgiving for beginners, once they are set up correctly. Root visibility makes it easier for you to identify potential problems early on before they get worse.

If you want to find out more about NFT hydroponics or which sensors we suggest for your hydroponic operations to be successful, please feel free to reach out to the world-class team at Atlas Scientific.