A Step-by-Step Guide to Setting Up an NFT Hydroponic Cannabis Grow System

You might have heard about NFTs — no, not the digital art kind that was trending on the internet last year. We're talking about the nutrient film technique — a hydroponic setup that's all about growing cannabis in a clever, efficient way. 

In this setup, you don't need to use soil at all. It allows your plants to grow in a nutrient-rich water film, which maximizes their potential while being stress-free for you. So, if you're ready to start growing cannabis using this method, what are you waiting for? Learn about growing and setting up an NFT hydroponic cannabis grow system in this article. 

What is the Nutrient Film Technique? 

Image Credit - Xabii

The Nutrient Film Technique (NFT) is a hydroponic method where part of the plant's roots are submerged in a thin layer of nutrient-rich water, while the rest of the roots remain exposed to air. 

This combination is key, as roots need both water and oxygen to thrive. Without oxygen, your plants won't grow properly no matter how nutrient-packed your water is. So, you need to make sure that you strike this balance when setting up your NFT system for cannais. 

In an NFT system, your cannabis plants sit in long channels or troughs, held in place by net pots. A water pump keeps the nutrient solution flowing across the bottom of the troughs, ensuring that the roots get a steady supply of both nutrients and oxygen.

This efficient setup helps maximize nutrient absorption, promoting healthy growth without the risk of drowning the roots. As a result, your plants can grow to their full potential while producing high-quality buds. 

Benefits of NFT for Growing Cannabis 

The Nutrient Film Technique (NFT) offers several advantages for cannabis growers:

1. Efficient Use of Nutrients and Water

NFT systems use a thin film of nutrient-rich water that continually flows over the roots. This recirculation minimizes the waste of water and nutrients, as the unused solution is recirculated back to the reservoir to be reused in the system, unlike other hydroponic setups. This efficiency is especially useful when there's less water or it is costly to get the nutrients. Also, since you can adjust the nutrients directly in the reservoir, any deficiencies can be quickly corrected to keep plants at optimal health. 

2. Oxygen-rich root zone 

NFT systems expose the roots to the nutrient solution and oxygen, thereby allowing direct access to oxygen. 

In NFT systems, the roots are exposed to air and nutrient solution, allowing them to reach their oxygen supply directly. Since cannabis plants require oxygen for robust root growth and nutrient absorption, this is especially beneficial. The roots are not submerged in the nutrient solution; instead, a thin film of nutrient solution continuously flows over the roots so they aren't deprived of oxygen. In turn, this reduces oxygen stress and creates ideal conditions for rapid root growth. The oxygen-rich environment helps good microbes grow which can help the absorption of nutrients and keep the plants healthy.

3. Accelerated Rate of Growth

The roots of cannabis plants have constant contact with oxygen, water, and nutrients. In other words, they have everything they need to perform well. As a result, the plants grow faster than those in soil or other traditional hydroponic systems. In addition, the plants don't face any interruptions with nutrients, which is a common problem if you have to feed the nutrients yourself. Therefore, you can harvest multiple times as they mature faster. 

4. Simple maintenance and monitoring

NFT systems are easy to design and typically contain a nutrient reservoir, pump, channels, and tubing, so it's pretty easy to monitor and manage nutrient levels, pH, and EC (electrical conductivity). The NFT system automatically supplies water and nutrition, unlike other systems where you have to do that manually. Changing any nutrient in the solution allows simultaneous adjustment of all plants in the system. Normally, maintenance involves checking for clogs in the channels or tubes and cleaning them thoroughly albeit periodically. 

5. Space Saving

You can design the NFT in a small room which is suitable for growers with limited space. Many growers set up NFT channels vertically or in stacks to maximize their planting area and limit their footprint. It's very efficient in occupying space and is most useful for indoor cannabis grows that aim to pack more plants without losing quality.

6. Less Chances of Root Disease

NFT systems lower the risk of root diseases such as root rot, as the roots are not submerged in the water for long periods like in other hydroponic systems. Because roots are always subject to a low but continuous flow of nutrient solution, they do not become waterlogged which minimizes disease-causing pathogens, making NFT cleaner and safer than other hydroponic or soil-based methods.

7. Less Overall Costs

Usually, NFT systems use less growing medium than other systems: plants are grown in net pots using only a small amount of medium, which is either Rockwool or clay pebbles to stabilize the roots. You don't have to purchase a lot of growing media either, which will help you reduce the costs a bit. 

Moreover, as the same nutrient solution constantly flows, there is less need for water and nutrients over time, so you save a little more with that. Over time, this system is very cost-effective, especially if you have a large tent. But, initially, the costs are high, and we will discuss that in the next section. 

8. Environmentally Friendly

Since NFT systems save more water and nutrients compared to other hydroponic systems and soil cultivation too, it's more environmentally friendly to grow cannabis indoors. NFT systems reuse water, which can be particularly helpful if you live in a region that suffers from a shortage of water. 

Moreover, using a precise amount of nutrients at the right time reduces the chance of nutrient runoff. 

Disadvantages of NFT for Growing Cannabis

NFT hydroponics offers a variety of benefits that make it an attractive system to grow cannabis. As such, you can achieve healthy, quick-growing plants through this effective method. 

However, they do have a few challenges you should be aware of. Let's take a look at them. 

1. Possibility of System Failure

NFT relies on the nutrients flowing constantly. Therefore, a power outage, pump malfunction, or clog in the tubing can cause the entire system to fail. If this occurs, the roots that are exposed to air can dry out pretty soon. Once the roots are stressed, the plant can struggle and even die if you don't act quickly. To prevent this, you must have a power backup to ensure the setup is seamless and the plants are happy. This also means that you should monitor it carefully to prevent problems. 

2. Gets Clogged Easily

In NFT, nutrients are delivered to the plants through small channels; therefore, the system may clog if algae or roots build up in the channel, or if there's debris in the reservoir. Small blockages can disrupt the nutrient supply to plants and affect their growth. Thus, you should clean the system regularly to avoid channels being blocked and stop algae from growing.

3. Not Suitable for Large Plants

The channels restrict root growth so NFT systems are a good choice for small and medium-sized plants, but not so much for large plants as they have extensive root systems. In short, NFT systems have very little space for roots to grow, so you'll be better off using other types of hydroponic systems like DWC that can handle larger plants. 

4. pH and Nutrient Imbalances

Imbalances in pH or nutrient levels can quickly affect all plants as the nutrient solution is recycled in NFT systems. Cannabis is a plant that is sensitive to fluctuations in pH. So, you should correct any fluctuations immediately to avoid damage to the plant or nutrient lockout. To prevent this, watch the pH and nutrient levels regularly so that you can adjust them when required. 

5. High Initial Expenses

Even though NFT systems are cheaper in the long run, the initial setup can be quite costly as it requires good pumps, timers, reservoirs, and a strong structure for the channels. You need good equipment so that systems are reliable and won't break down easily. In addition, setting up lights, climate controls, and monitors can become expensive especially when building a system in-house.

6. Sensitive To Temperature

Due to exposure to the growing room's environment, the nutrient solution in the NFT system is sensitive to temperature changes. Make sure the temperatures are within 64°F to 68°F (18–20°C). 

When temperatures go up, the temperature of the nutrient solution can also go up, which reduces the oxygen available to the roots and increases the risk of root diseases. This means you should pay extra attention to the grow room temperature and cool the nutrient reservoir, if needed, especially in warmer climates.

7. Not recommended for Beginners

NFT setups require an understanding of hydroponics, nutrient management, and monitoring which might be difficult for a beginner. Even a small mistake in pH, nutrient concentration, or flow rates can cause plant damage. For a commercial crop and recurring management, consistent and immediate issues may arise in NFT, which is why it is more suited for experienced growers.

To cultivate cannabis successfully with NFT, you must balance these challenges with the advantages the system offers.

How to Set Up a DIY NFT System for Growing Cannabis?

Now that you understand the benefits of using NFT to grow cannabis, let's get into it without further ado. You can build your own system at home. All you need are basic DIY skills and some hydroponic know-how to get started.

Gather Your Supplies

To create your own NFT system, you'll need two main components: a reservoir and a grow tray, but there are a few other things, too. So, here's what you'll need:

1. Reservoir tank of at least 20 liters

This is where your nutrient solution is held and from which it is pumped through the system. The water tank which is commonly called a reservoir needs to be big enough to have sufficient water for your plants. The top of the tank should have a lid to reduce evaporation and contamination. 

2. Grow tray with troughs

These hold the plant roots and allow them to receive a thin film of nutrient solution. As they are tilted slightly, the nutrient solution flows easily. Just remember, while PVC pipes are a popular choice, they can lead to uneven nutrient distribution, with plants in the middle thriving while those on the ends may struggle. You can use flat-bottom channels to prevent this issue. 

3. A framework or benches for your grow tray

4. Net pots

These are designed to support the plant and give its roots something to cling to. You should place them in the channels in such a way that their bases are just touching the nutrient solution and allow the roots to grow downwards into the thin film of nutrients. Also, when it comes to seedlings, you have two options: place them directly in the holes or use net pots for better root protection. If you choose net pots, fill them with Rockwool or hydroton, but don't overpack — this helps the roots reach the nutrient solution.

5. Growing Medium

Although NFT systems do not require a large amount of medium, a little Rockwool, clay pebbles, or coconut coir placed in net pots can keep seedlings anchored.

6. Submersible water pump with a flow rate of 1 liter per minute

Typically, a submersible pump is used to move the nutrient solution through the channels. Go for a pump that can modify the flow rate, ensuring that the nutrient flow is the same in all areas.

7. Air pump and air stones 

An air pump and air stones are optional, but if you put them in your reservoir, your nutrient solution has a high level of dissolved oxygen (DO). In most cases, the oxygenation of water through the thin film of nutrients is sufficient, but if your climate is warm, then having an air pump and stones can assist with oxygenation. 

8. pH and EC meters

Accurate pH and EC (Electrical Conductivity) meters are essential for monitoring the nutrient solution. The pH needs to remain between 5.5 and 6.5 and the EC levels will change through the growth cycle, but these should be adjusted to cannabis.

9. Water Thermometer

It is useful to measure the temperature of the nutrient solution which must be within 64–68 °F (18–20 °C) to avoid overheating and ensure there is enough oxygen.

10. Tubing and Connectors

Tubing connects the reservoir to the channels and also helps the nutrient solution flow back to the reservoir. Use good quality and flexible tubing to limit leaking and allow easy setup adjustments. To regulate the flow within channels, you can use small drip-style tubing. 

11. A water cooler or heater for temperature control 

Follow These Steps to Set It Up 

Once you have everything sorted, you can start setting up your NFT for cannabis using the following steps. 

• Cut the Pipe and Drill Holes

Start by grabbing a PVC pipe and cutting it to your desired length. This will be the backbone of your grow tray.

Then, it's time to make some holes! Depending on how many plants you want to grow, drill holes in the pipe that are just the right size for your net pots. Be sure to measure the pots first so they fit snugly. 

Don't forget the end caps! Drill holes in them too, as they'll help secure your system later. You'll also need to drill two more holes at the top and bottom of the pipe for nutrient flow. 

• Set Up the Reservoir

Next, you'll need a reservoir that holds at least 20 liters of water. Make sure it's completely lightproof to avoid any algae. Drill two holes in this reservoir as well.

• Build the Pipe Stand

To keep your setup stable, create a stand using wood, PVC, or metal. Ensure that one end of the pipe is slightly elevated, giving it that essential slant for nutrient flow.

• Connect the Reservoir

Using rubber tubing, connect the reservoir to the higher end of your grow tray. Then, run another pipe from the lower end of the tray back to the reservoir.

• Plug in the Equipment

Add your submersible pump to the reservoir and hook it up to the pipe leading to the tray. If you're feeling fancy, throw in an airstone for extra oxygenation!

• Fill the Reservoir

Now, pour in your water and nutrient solution, then fire up the pump to get that nutrient flow going.

• Place the Seedlings

Finally, place those net pots filled with your seedlings into the holes you drilled earlier.

That's it. Your NFT hydroponic system is all set and ready.

Factors to Consider When Using NFT to Grow Cannabis 

Image Credit - Agonias

Apart from the steps mentioned earlier, you also need to focus on a few things to get the best results. Here they are. 

• Gradient or Slope

The angle of your NFT channels is crucial for nutrient flow. A slope of 1:30 (3.33%) or 1:40 (2.5%) helps prevent nutrient pooling, which can cause root rot. You can create this slope using frames, benches, or a sloped floor.

• Nutrient Flow Rate

This flow rate is essential for delivering the right amount of nutrient solution to your plants. So, you need to aim for a flow rate of one liter per minute for optimal growth. 

However, when introducing new plants, reduce it to around 500 ml per minute. This slower rate helps prevent overwhelming their delicate roots, allowing them to acclimate without the risk of drowning. 

You should also try adjusting the flow rate based on your plants' needs as that can further help you fine-tune the flow rate as per your plant's requirements. 

• Channel Length

Keep channel lengths between 30 and 40 feet for even nutrient distribution. Longer channels may require multiple nutrient feeds to ensure all plants thrive.

Extra Tips for Growing Cannabis With NFT Technique

To get the most out of your NFT setup for growing cannabis, let's take a look at some awesome tips:

• Run a test of your system to understand how it works before planting your cannabis 
• Monitor and top off your nutrient solution at least once a week as the EC and PPM can change over time 
• Replace the nutrient solution every ten days to keep it fresh and beneficial for your plants
• Aim for a pH between 5.8 and 6.2 for optimal growth, as this range works best in NFT systems
• Ensure all channels and the reservoir are light-tight to prevent algae growth, which can lead to root rot
• Give your plants plenty of room to spread out, as NFT cannabis can grow rapidly
• Only introduce seedlings with established root networks to ensure they can absorb nutrients effectively
• If your system is noisy, place a spreader mat under the channel and reservoir to dampen sound and improve nutrient flow

Follow these steps and tips, and you'll be on your way to growing excellent NFT cannabis plants! 

1. Testing 

Before putting your cannabis plants into your NFT hydroponic system, it's important to do a proper test run of it. If you take a few hours to assess your system, it will help you to avoid complications in the future. 

You should test your system as you'll have several components working together: the pump, the tubing, the reservoir, the channels, and whatever sensors you've put in place to monitor them. Everything has a role to play in transporting nutrients to your plants consistently and efficiently. Even a small malfunction can affect the whole process. Thus, doing a run test before planting confirms that all systems are working correctly. Additionally, it also ensures that there is no risk of running into problems of nutrient deficiency, dry roots, and uneven growth affecting your plants.

Here's how you can test your system: 

2. Testing the flow rate and distribution

First, fill the Reservoir with only water to test the flow and circulation without wasting nutrients in case the need arises to drain and readjust. To mimic actual conditions, use water at the same temperature you will ultimately use. 

Next, turn on the water pump. Watch the water going through the tubing from the reservoir to the channels. It should be seamless and flow evenly along all the channels because NFT uses a thin film of nutrient solution and not a deep layer. This is important for oxygen access and to ensure that all the roots are supplied nutrients evenly.

Now, inspect each channel to confirm the water flow water is uniform from the beginning to the end. If you notice water pooling in an area, it could indicate that there are clogs. Adjust the channel angle slightly if necessary as the water will flow naturally due to the force of gravity. This prevents pooling and keeps the flow rate consistent. 

Next, you should check the water flow back to the reservoir. When the water reaches the end of the channel, it should flow smoothly back to the reservoir. Make sure all channels drain properly, as blocked and/or slow-draining channels can cause spillover or uneven distribution. Most problems here can often be fixed by altering the return flow tubing or checking for blockages. 

Lastly, check that the flow rate is consistent in all channels.

In bigger NFT systems with more than one channel, it is important to check that each channel receives the same flow of water. When water flow rates are not the same, some plants will grow faster than others. To achieve better water distribution, make pump adjustments or install flow regulators if necessary.

• Find and fix any leaks or clogs.

While the system is operating, check all connections between the tubing, channels, and tank. Watch out for any dripping, leaking, or odd noises, indicating air bubbles in the tubing. Air bubbles and leaks can obstruct nutrient flow reducing overall effectiveness, so if you notice any loose connections, tighten them with haste. You can also use a tape sealant if necessary. 

If you notice any clogs, clean the tubing or filter it for any debris. Older systems may have clogs caused by algae or salt buildup, so check these areas too.

• Test run for 24 Hours if possible.

Running the system for 24 hours, time permitting will give you the best sense of whether it's set up for continuous operation. With this longer test period, you can spot things that wouldn't be shown in a shorter test, like small leaks or a temperature shift. After the test, check the system for the pump overheating or if there's any major water loss due to evaporation, and any clog that may have developed over time.

3. Choose the right nutrients 

Choosing a suitable nutrient solution is important as cannabis has a unique nutritional requirement at each growth stage. The need for nutrients at the vegetative stage is higher for nitrogen (N) since it is the vegetative growth stage. Choose a nutrient blend with a higher NPK ratio in nitrogen like 3-1-2 or something similar. Most brands will recommend adding calcium and/or magnesium to the nutrient solution to prevent deficiencies. As the plants move towards the flowering stage, they will need nutrients with more phosphorus and potassium. Thus, fertilizers with 1:4:5 NPK or something similar are effective for flowering. Of course, you'll also have to use micronutrients at every stage including nutrients like sulfur, iron, copper, boron, and more to help the plant grow well. Although these micronutrients are required in very small quantities, plants cannot function without them. 

Remember that although plants need a sufficient amount of nutrients, highly concentrated nutes can be very bad for the plant. Therefore, make sure you're using nutrients in the right quantity and don't use too much or less of them. 

4. Watch the EC

As time goes by, the water evaporates and the plants also take in nutrients so the EC can start fluctuating. Thus, to keep it consistent and ensure that the nutrients are available for the plants, try to check and top up your reservoir at least once a week. Use an EC meter to monitor nutrient concentration and make adjustments as required. When the solution levels stay stable, it helps to prevent deficiency or toxicity from occurring when the nutrient levels fluctuate. 

5. Replace the nutrient solution every ten days

Constantly replacing the nutrient solution keeps it fresh and free of any imbalances. This is because unused nutrients can accumulate or decompose over time, which can create toxic situations for your plants. Make sure you empty and refill the solution in the reservoir every ten days to balance it. After each change, clean the reservoir, channels, and tubing to avoid algae and salt build-up that will block them.

6. Keep the pH in the range of 5.5 – 6.5.

In hydroponic systems, it is important to maintain an optimal pH range for proper nutrient uptake. In NFT systems, cannabis grows best with a pH between 5.8 and 6.2 although it's okay if the pH is between 5.5 to 6.5 so that the roots can take up nutrients. Use a reliable pH meter to check the pH every few days and also use adjusters when necessary. 

7. Make sure channels and reservoirs are light-tight.

Algae grow in the light, which means they can grow in channels, increase the pH, and also cause root rot, which can kill your plants pretty quickly. To prevent algae growth, use opaque materials to cover the reservoirs and channels. Alternatively, use lids to block out light. Also, look for any small leaks where the light may come in and cover those, too. Algae can grow and spread on the surface of pools. If you spot algae even after taking these precautions, simply scrub any affected areas straight away to stop it from spreading.

8. Allow lots of space for your plants to grow

Cannabis plants that grow in NFT systems often exhibit vigorous growth. Thus, they will need enough space to expand, which means that you should space your plants at least six to twelve inches apart for adequate light and airflow.

You can also support the plant using stakes if it gets too heavy with buds during flowering. 

Summary: A Step-by-Step Guide to Setting Up an NFT Hydroponic Cannabis Grow System

Setting up an NFT hydroponic system for cannabis might seem a bit daunting at first, but with the right tools and a sprinkle of patience, you'll be reaping the rewards in no time. Just remember, it's all about maintaining balance — between nutrients, water, and light — to ensure your plants grow strong and healthy. 

Here's a quick summary of the benefits of this system: 

1. Up to three times the yield compared to traditional methods, thanks to the continuous nutrient supply, speeding up growth.
2. You have precise control over pH levels, nutrients, and water, helping plants produce high-quality buds.
3. While setting up an NFT system can be tricky, maintaining it is straightforward compared to other hydroponic techniques.
4. The system recirculates water, minimizing waste, and avoids groundwater contamination while ensuring efficient nutrient use.
5. Since NFT doesn't use soil or other organic media, it significantly reduces the risk of pests and diseases.

Remember to monitor your system regularly, though. Your plants will thank you with vibrant, lush buds in no time. 

Whether you're a seasoned grower or just starting, there's nothing quite like the satisfaction of cultivating your own cannabis, and the NFT technique can help you get there easily.