Nutrient Film Technique (NFT) is one of the most popular of all hydroponics systems. NFT is an easy way to get your plants the water and nutrients they need, while avoiding some of the common problems that plague traditional gardening methods.
The main reason people choose NFT over other systems is because it doesn’t require expensive pumps or costly electricity-saving timers; instead, you can use gravity to control how fast the water flows through your system.
In this complete NFT guide, I’ll be explaining everything you need to know about Nutrient Film Technique. I’ll show you just what NFT is all about and why many growers choose it over any other hydroponics system.
What is Nutrient Film Technique and How Does NFT Work?
Nutrient Film Technique is similar to Ebb and Flow in that the plants sit in a grow tray located above a central reservoir. This reservoir is filled with a water and nutrient solution that is used to feed the roots for healthy plant growth.
As in ebb and flow systems, a pump is used to pump the nutrient-enriched water up to the plants. Ebb and flow systems work by utilizing flood and drain mechanics. It first floods the roots and then drains periodically.
The different with NFT setups are that they are active systems as the water and nutrient pump through the channels constantly. The grow tray that the plants grow on is angled slightly to let the water run to a drain on the lower side of the channel, which then returns the unused water nutrients to the nutrient solution reservoir.
This method means that there’s a constant flow of a nutrient solution down channels. The plants’ roots touch the shallow film of nutrient solution flowing down the grow channels, absorbing nutrient water as it flows by.
These are the main components of an NFT system and how they work are described below.
- A central reservoir that holds the complete nutrient solution mix
- A water pump to circulate the nutrient water up to the grow tray
- Tubing to connect the pump to the Channel / Grow Tray (preferably flat-bottomed channel)
- The nutrients flow through the Channels and the grow tray for absorption by the plant roots
- Plants are situated in a growing medium (optional)
- A water return system with a drain tube (this can be as simple as a hole in the lower end of the grow tray)
The plant roots grow into a thick root mat on the bottom of grow tray, and they absorb all the nutrients and water as the water flows over them.
The constant flow of nutrient solution with oxygen provides plant roots what they need in a way that helps to prevent drowning. The plant roots aren’t submerged in water like with Deep Water Culture systems.
Popular Plants To Grow In NFT Systems
One of the great benefits of Nutrient Film Technique systems is their sheer versatility when it comes to the types of plants you can grow using them. But there are still some plant requirements, because NFT conditions for plants aren’t always suitable.
Generally, smaller, fast-growing plants are ideal. You’ll want to stay away from larger plants, like fruit-bearing plants, that will require physical support to hold up.
Top-heavy plants like tomatoes and cucumbers will need proper support systems. Self-standing trellis systems are doable, just a bigger pain for NFT due to all the channels.
Here’s a list of the popular types of plants to grow with NFT:
Leafy Greens
This is one of the most popular categories for any hydroponics system, especially NFT, because they’re high yielding and lightweight, fast growing plants. Many types of lettuces are great for growing:
- Romaine Lettuce
- Red Lettuce
- Bok Choy
- Spinach
- Kale
- Broccoli
- Raab
Herbs
Herbs are lightweight plants that are a popular choice for growing in NFT systems. These are vigorous-growing plants, so you’ll get the satisfaction of seeing yields quickly. Common herbs to grow are:
- Basil
- Thyme
- Cilantro
- Parsley
- Sage
- Thyme
- Oregano
- Mint
Fruits and Vegetables
One of the great pleasures of hydroponic systems is harvesting your fruit and vegetables and having them on the dinner plate in mere seconds after picking. Here are some of the more common types that are good with NFT designs:
- Mini Peppers
- Beefsteak Tomatoes
- Cherry Tomatoes
- Chili peppers
- Mini Cucumbers
- Zucchini
- Strawberries
- Green Beans
Related article: Hydroponics Plants List
NFT Advantages
Growing plants and crops using NFT’s simple design plans has many advantages and benefits.
Simple to Set Up and Use
This technique uses one pump as the only mechanical part of the setup. It relies on gravity to ensure the water flows through the channels and is fed back to the reservoir.
Once you have the system up and running, it’s simply a matter of monitoring the stream of nutrient water quality and ensuring the correct mix of water nutrient solution is flowing through the NFT channels.
Efficient Use of Nutrients
The plants only take the nutrients they require as the water passes over the roots. The flow of nutrient-rich water creates a shallow nutrient solution film in the dark tubing channels that allows for optimal nutrient absorption, and access to oxygen.
The nutrient feed flowing through the tube-like channels will result in nutrient consumption that’s 100%, but that doesn’ t mean the excess nutrient solution is wasted. Unused nutrient solution flows through to the nutrient return pipe into the reservoir to be used again.
Environmentally Friendly
The nutrient solution recycling makes NFT very friendly to the environment. NFT uses less water and no pesticides.
Even though the water is constantly flowing throwing the series of channels, NFT uses up to 95% less water than traditional gardening or farming methods. Any unused water is recycled within this closed system.
Plants grown with a soilless method are also less prone to pest infestations, which means there’s no need to use insecticides. No chemicals will taint the water and plants that would otherwise lead to the death of crops.
Fast Growth and High Yields
By delivering the perfect amount of nutrients directly to the plant’s roots, growth and yields are faster and higher than those achieved using a traditional method of soil gardening.
Plants grown hydroponically will generally produce 30% to 40% higher yields than when using traditional methods.
NFT systems also provide sufficient oxygen levels with the constant flow of nutrient concentration and water, so no need to worry about the supply of oxygen
Reduced Salt Build-Up
Water consistently flowing through the root system helps to flush out build-ups of nutrient salts.
NFT Disadvantages
Overall, NFT are easy to use and simple systems that offer many benefits. However, no system is perfect and there are a few downsides.
Pump Failure
Because this system requires a constant flow of water over the roots, a pump failure can be devastating. If the pump fails or the power fails, then a whole crop can be wiped out within a day.
If there’s no flow of water to plants, there’s no absorption of nutrients by the roots, so nutrient imbalances and nutrient deficiencies will result.
For this reason, it is always recommended to have a backup ready – a spare pump and an alternative power supply.
Plant Types
Plants that have long taproots, don’t grow well in NFT systems. Examples of long taproot plants include carrots, radishes, and beets.
Limited Space
The size of the grow can be limited by the space available for the circuit of channels and larger tubing for the root mass to grow into.
As for the reservoir, a good rule of green thumb is for every 10 plants you want to grow, add 1-gallon to your reservoir capacity.
Feeding Plants Nutrients
Adding nutrients to these systems couldn’t be simpler. The tank is easily topped up with a water and nutrient mix. There are some factors that you should keep in mind with NFT.
Stick to the nutrient ratios and dosage rates recommended by the manufacturer, unless you have specific nutrient levels you’re looking for. Overfeeding or underfeeding can hinder a plant’s growth rate or even kill the plant altogether.
If you do find that the plants aren’t taking to the recommendations on the bottle, do some testing. Start with half strength nutrient solution and then move your way up to manufacturer’s suggested dosages. See what changes there are with the roots. Healthy roots are white and bushy.
Periodically drain the reservoir and refill with a fresh mix of nutrients and water to keep the environment clean for the roots. This ensures that salt build-ups caused by unused nutrients don’t become a problem.
Regularly monitor the water quality, pH levels, and adjustable flow rates.
Parts of a NFT Hydroponic System
In this section, I detail all the parts required to build an NFT system. One of the great benefits of these systems is that anyone with a modicum of DIY knowledge would be able to build a complete NFT system easily at home.
Grow Tray / Channels
The tray, or channels, are what your plants sit in. Many hobbyists use PVC pipes for this, however, these aren’t ideal for allowing even distribution of nutrients to the roots. The curves of PVC mean nutrient uptake is uneven, and if your channel slope ratio and flow rate are perfect, the plants will be affected.
It’s also recommended to use shorter channels. Channels longer than 30-40 feet will start to see nutrient deficiencies. Water has a harder time getting all the way down and all the plants early in the channel will absorb most of the water and nutrients.
For channel slope ratios, the general guideline is for 30-40 inches of channel length, drop the channel one inche down. If possible, leave room for adjustments in channels. Depending on the plants you’re growing, the roots could grow larger and water may have a tougher time getting through the channel, in which case you’d want the ability to lower the channel more.
A flat tray or channel is the better solution to use, like the ready-made NFT channels from the reputable CropKing systems (below).
A great beginners option for NFT is to get a full NFT grow kit setup, like this one from Vivosun. It provides you all the necessary parts, including the 3 layers of irrigation tubing pipes, water pump, automatic timer, nest baskets, and planting sponges.
The major advantages of a system like this is it’s a hassle-free nutrient film technique hydroponic system. It gives you what you need and you don’t need to worry too much about things like rate of flow.
While a full kit like this is great for beginners, the drawback is it’s not as scalable.
Water Reservoir
The water reservoir is a vital part of any NFT setup. It’s the chambers for nutrient solution, so it needs to hold enough to keep your plants fed and watered without having to continuously refill it.
The reservoir is normally situated below the grow tray and the water is pumped up to the plants and returns to the reservoir through gravity.
Plastic totes or five-gallon plastic buckets for smaller systems are great for NFT. You don’t want to get a clear, transparent tote or basket either. Go with a black or other dark colors. That prevents UV rays to shine through the container to the water, which will lead to algae and root rot. Here’s an example of a plastic tote that’s popular:
Also, look at the plastic materials used to make sure they’re not harmful to plants. For example, avoid plastics that contain BPA. All plastic containers have recycling codes printed on them, so buyers know what kind of plastic is being used.
Look for ones with the #1, 2, 4, or 5 on them. Most that’re made specifically for gardening will be #5, but it’s also expanded now with advances in plastic technology.
Submersible Water Pump
The water pump is one of the most essential items for a successful NFT system. This is not an item to try and save a few bucks on.
The pump works 24/7 delivering the nutrient-infused water directly to the plant roots. This means that if there’s a pump or power failure, or not enough water is being pumped through, the entire crop is in jeopardy.
For NFT, the recommended flow rate is usually 1/4 to 1/2 gallons (1-2 Liters) per minute or 15-30 gallons (60-120 L) per hour) for each channel.
A water pump like this one from Hydrofarm will be good to scale with. It pumps water at 400 GPH (gallons per hour) and will support up to 40 gallons of water in the reservoir.
Tubing
The tubing is what delivers the water from the pump up to the channel and grow tray of plants. Any tubing that is of the correct size for your pump will do, with one caveat. The tubing should be black or dark-colored.
Like containers, non-transparent nature helps stop algae growth by blocking out the light that allows microbes to grow.
Simple tubing like this one is good.
Air Pump and Air Stone
This is optional, as NFT systems are already fantastic at ensuring plenty of oxygen is available to the plant’s roots.
However, many growers will swear by the beneficial effects that adding these items can provide. These are inexpensive items that can be purchased at any pet store.
By using an air pump connected to an air stone you ensure that the water that is pumped to the plants is oxygenated. Air stones and their micro-pore design deliver the aeration of nutrient water. A simple, inexpensive setup with these two is a good option:
Growing Medium
Finally, you need some growing medium for your seedlings and plants. There are several types of medium available. One of the most popular for NFT systems is Rockwool, but others that can be considered include: –
- Coconut Husks (sometimes called coco coir)
- Expanded Clay Pellets
- Perlite
- Growstones
- Gravel
What you choose is down to personal preference and also the type of plants you intend to grow. However, most growing mediums will work with any type of plant.
Check out this NFT farm setup. Really cool to think about the possibilities with scaling up if you want to feed more than just your own family.
Final Thoughts on NFT Systems
There are many soilless systems, like basic wick systems and aeroponic systems, out there for hydroponic growers. NFT is a popular choice for hobby and commercial growers as NFT offers more optimal conditions for growing.
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