nft growing system

NFT Hydroponics – A Beginners Guide

What Is NFT Hydroponics?

NFT stands for nutrient film technique and it is a method of growing plants that does not require soil. NFT is a versatile hydroponics system in which a pump is used to deliver fertilized water continuously. The solution that delivers water nutrients and oxygen to your plants is designed to flow over the roots in a thin film, hence the name; nutrient film technique.

The constant stream of nutrients flows over the bottom part of the roots while the upper part of the plant is left open to the ideal environment created inside the growing chamber, ensuring that the plants receive the optimal amount of oxygen.

Plenty of oxygen is needed for plants to thrive. This is one of the key components of hydroponics. Plants require carbon dioxide for photosynthesis and oxygen to absorb nutrients. when the roots of plants have an increased access to oxygen the plant thrives.

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How does NFT Work?

The main difference between Nutrient Film Technique hydroponics and ebb and flow hydroponics is the configuration. In NFT hydroponics, a tube like channel holds the roots. It is angled so that the nutrient solution can easily flow through it. There are usually several growing channels in one NFT hydroponic system.

There are holes in the top of the growing channel for the plants. The roots can stay in darkness while accessing the flowing nutrient solution while the tops of the plants poke out of the holes above accessing the light they need. NFT hydroponics eliminates the need for soil or potting mix, the only extra thing growers will need are net pots to provide extra support for their plants.

NFT hydroponics utilizes a pump to deliver fertilized water from the high end of the growing channel all the way to the bottom end of the channel where it is returned to the reservoir at the top. It is a circuitous system allowing the nutrient solution to be recycled so less water and nutrients need to be used.

Benefits of NFT:

The advantages of using nutrient film technique hydroponics over other hydroponic systems centre around its functionality and simplicity. The following list highlights some of its greatest benefits:

  • NFT Hydroponics are not complicated to build and simple to run
  • Can be changed with little problem to suit different spaces or plants
  • Does not cost a lot to build
  • No need for soil
  • The flow of the nutrient solution is constant which eliminates the need for aeration
  • No need for timers because the water flows continuously
  • The fertilized water is recycled meaning less water needs to be used

Downsides to NFT:

There are a few drawbacks to using NFT hydroponics. The most obvious is that it relies on an electrical pump running day and night. If there is a disruption to your electricity for any reason and the pump stops for any length of time the roots of your plants will suffer and the plants could suffer irreparable damage.

The second drawback to nutrient film technique hydroponics is that it is not effective for fruit-bearing plants or plants with large root systems.

NFT hydroponics works well for small, quick-growing plants such as lettuce, herbs and leafy greens. Plants that grow large roots quickly are likely to fail in this system because the extensive root system will fill the growing channel and stop the flow of fertilized water.

Growing fruit-bearing plants will be difficult using NFT hydroponics for a couple of reasons. First, it is better if fruiting and flowering plants are allowed to dry out between waterings which is obviously not possible using NFT hydroponics as the nutrient solution flows continuously. Second, fruiting plants need a lot of extra nutrients when the plant is in a fruiting stage. The recirculating system of fertilized water would have to be very closely monitored to ensure the plants are getting what they need.

Beginners Tips to NFT

18°C & 20°C Nutrient Solution

Use a nutrient thermometer to ensure that your nutrient solution remains constant at the perfect temperature. The ideal temperature will be between 18C- 20C. Use a heater and chiller to maintain this temperature.

Constant Feed Pump

Keep your nutrient solution pump running 24/7. The point of the pump is to keep the roots of your plants constantly wet. If it is turned off the roots will quickly dry out causing all kinds of problems.

Dried out roots will result in cell damage, a dead root mass and wilted plants. Simply turning your pump back on will not solve your problem as your dead root material will become flooded with the nutrient solution which will cause root diseases.

There are times you will want your plants to receive less water, such as when they are newly transplanted. If there is a situation in which you want your roots to receive less water do not turn off the pump completely, just turn it down so the water flow is very light. You can slowly turn the water up as you need it.

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Roots Must Live in Darkness

It is important that the roots remain in darkness, light can cause the roots of your plants to grow algae. The algae will warm up the roots too much and compete with the roots for oxygen. NFT hydroponics systems come with a Correx cover to prevent this from happening.

NFT is used for Established Plants

Very new and tiny plants will not be able to thrive in your NFT hydroponics system. Ensure the roots are mature enough to deal with a constant stream of water. If the roots are immature the rockwool blocks soak up excess water and end up saturating the roots. This can kill your plants.

To ensure the roots of your plants are developed enough to handle your NFT system, start by establishing the plants in 3 – 4″ Grodan Rockwool Transplanting Cubes. Once you see roots poking through the bottom of the rockwool blocks you will know it is time to introduce them to your NFT system. Your plants will be fine because the roots that emerged from the cube encouraged a big healthy set of roots to develop inside the cube.

Line up Cubes with Water Flow

When you are setting up your NFT hydroponics system you will notice the bottom of the Grodan cubes have grooves etched into them. These grooves are meant to help with the water flow. Line them up so the water can flow through the grooves, allowing the roots to grow.  Make sure that you line them up with the flow of water.

When Aerating a Tank:

The pump system in NFT hydroponics ensures that your nutrient solution is already aerated. There are a couple of things to consider if you are aerating your tank as well.

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1. It Must be an Appropriate Solution for Aeration

There are some plant nutrient mixtures that are not meant to be aerated. Make sure you check before aerating yours.

Organic ingredients such as seaweed or molasses are not meant to be aerated and they will become oxygenated if you aerate.

2. Reduce Strength

Remember that extra oxygen will increase your plants nutrient uptake. If you are aerating, you also need to lower the strength of your nutrient solution so that your plants don’t get overfed.

The precise strength of the nutrient feed may change with the type of plants you are growing, your environment as well as how hard your water is.

With the use of filtered water, your nutrient feed strength should be about 12 – 14 CF (1.2 – 1.4 EC).

Learn how to setup your Grow Tent here.

You can browse all of our plant nutrients for sale here.

Maintain Water Flow with Single Mat Layers

You only need one layer of spreader mat. Spreader mats are used so that your water is even across all channels.

If you have more than one layer the plants will not grow as well because the water flow will be slowed.

Who are we? We’re Acorn Horticulture, a hydroponics store based in Sheffield but serving the entire UK with products to help boost your indoor growing.

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string of hearts trailing plant

String of Hearts Propagation Guide

A String of Hearts is a pretty trailing houseplant, also known as Ceropegia woodii or Rosary Vine. This semi-succulent plant is easy to care for and a perfect plant to begin with if you are just starting out with your indoor gardening.  The Rosary Vine falls into the same category as another gorgeous succulent vine; the Hoya.

Tips on Growing String of Hearts/Rosary Vine

The String of Hearts is a wispy vine; it is known for its pretty heart shaped leaves and gorgeous pattern. A healthy vine will produce a lot of small purple flowers on numerous stems.

Here are some things you should know if you would like to grow a Rosary Vine:

Outdoor Growing for Larger Trails

If you grow a String of Hearts as an indoor houseplant the trails of the vine may get as long as two feet but if you find this vine out in the wild the trails can grow as long as twelve feet. If you have the climate to grow your String of Hearts outdoors you will get much longer trails.

Heat Without Direct Sunlight

Rosary Vines like very bright light but beware of direct sunlight. Keep your plant in a west facing window with a little space between the hot glass and your plant. If you are planting it outside, provide some shade.

Dry Out Between Watering

The String of Hearts is much more tolerant of dry soil than wet. Allow your plant to dry out completely between waterings and when you do water – water sparingly. Your String of Hearts will rot in too much water. If you are in doubt, keep it dry, you can always add a little bit of water later.

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Propagate String of Hearts

A String of Hearts is fairly easy to propagate. There are a few different ways to go about propagating a String of Hearts.

Place Stem Cuttings in Water

The first is by placing the stem cuttings in water. This method is popular because it is so easy.

Cut vine pieces a few inches long and place the part you want to root in a vase of warm water.

Remove any leaves from the part that is in the water.

The part that is out of the water should have at least a few leaves. The water should be placed in a warm area with lots of bright light. Change the water every couple of weeks and just wait for your cuttings to root.

The time needed will depend on the amount of light and heat your cuttings are provided with.

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Place Stem Cuttings in Soil

Similar to the above method, you will need to take some cuttings from the mother vine. Place the cuttings directly into the soil this time. This method may be more successful if you place the cuttings in a mix specifically formulated for propagation.

Some people also report more success by dipping the ends of their cuttings into a  rooting hormone. Regardless, ensure that the soil you use is light and aerated so you give those tiny roots a fighting chance.

Leave your cuttings in a warm space with plenty of bright light. Keep them away from the bright sun and keep the soil a little bit damp. You can do this by watering about once a week. Be careful not to let your cuttings get too cold.

Using the Tubers

If you look closely at your String of Hearts you will see tubers of various sizes all along the vines. Fill a small pot with succulent and cactus mix and lay the vines with tubers on top. Cover them up with more of the potting mix. Water each week and keep your plant in bright light. With time, new roots will form from the tubers.

Tubers with Stems

This is not unlike the method described above except the stem is still attached to the mother plant. Lift the trails from the mother plant with tubers and place them in a separate pot with potting mix. Put a little more of the soil on top of the tuber, water it about once a week. Place it in bright light, keep it warm and wait. After the tuber has rooted you cut the stem. It won’t be long and you will have a nice new String of Hearts plant!

Visit the Acorn Horticulture blog for more guides like this, or visit our online store for all of the hydroponics products you need in the UK.

grow light bulb

Air Cooled Lighting

As temperatures increase in the summertime, the heat produced by lighting systems becomes more of a problem. Air-cooling these systems can become necessary.

How do Air Cooled Lighting Systems Work?

Air cooled reflectors use a glass bottom to create and airtight tunnel. Cool air is blasted through it, past the face of the lamps, taking away the excess hot air with it and cooling the lamp surface. The plants below still get the benefit of the light, but without suffering the effects of excess heat.

Be sure to keep the glass surface clean, however, as this is where beneficial light might be blocked or reflected by dust or moisture build-up on the glass surface.

Benefits of Air Cooled Lighting Systems

Removing heat with an air-cooled system prevents heat build-up in the summer, especially among the plants closest to the light sources. Lights can also be places closer to plants without burning them – this can become a factor especially as the summer season lengthens and plants grow higher, closer to ceiling-mounted lights. Small grow rooms, like those made in closet spaces, are especially susceptible to overheating, and a cooling system can save your plants from total destruction. It also reduces the strain on your ventilation system and can help to increase CO2 levels without having to add any through artificial means.

Common Misconceptions

There are a lot of myths around air-cooled light systems, so let’s address them directly.

Bulb Heat Is Lost

This is not quite accurate. HID lamps produce two types of heat when they are on. The first is convection heat. Air moving over the surface of the light can greatly reduce this form of heat by moving it away, down the duct, as it conveys the heat. In effect, it releases the heat at a destination outside of the grow room, where it otherwise would have been conveyed into it.

The second is radiated heat. Radiated heat moves in waves through the glass and into the room. Moving air past it does not significantly reduce radiated heat.

Air Cooled Reflectors Are Better Because They’re Closer

This is true in most cases – but keep in mind that the closer the reflector is to the tops of your plants, the more focussed the light is. If you want to cover a wider area, lifting the light may be of greater overall benefit than dropping it close. Aim for the optimal light levels at the plant surface: 800-950 micromoles/s.

Light Is Lost Through Glass Panel

High-quality, flat glass that is well-suited to this purpose will drop light efficiency by as much as 4-5%. This is less a factor than the loss of light produced when lamps are raised up higher to prevent overheating. Of the two options, the cooling system actually results in more light reaching the plants. Keeping the panes clean and the reflector closer to the plants will give best results.

Colder Air Blown Through Is Better

This is accurate, but the gases in the lamp’s arc tube need to be at the appropriate temperature to produce the optimal amount of light too, so overdoing it will create losses along with any intended benefits, and they will cancel each other out. The purpose of an air-cooled light is to remove excess heat, not to decrease as much heat as possible. It is about balance. A good rule of thumb is to use cooling air of a similar temperature to that in the grow room itself. This will also prevent the build-up of condensation or fogging on the glass, allowing for all of the available light to continue passing through the glass from the lamp and onto the plants below.

Want to Buy Grow Lights or Hydroponic Fans?

Here at Acorn Horticulture, you can buy a range of hydroponics online with home delivery or collection.

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grow tent setup

Grow Room Ventilation Guide

Article sections: Benefits | How To | Faq’s

One of the key benefits of indoor growing is that the season goes on and on and on – but there are some drawbacks too, if you’re not careful. A few simple tips and tricks will help to eliminate these though, and help you maximise the advantages.

Among the most important things to consider is airflow – achieved through proper ventilation. This is more than just popping a fan in a corner; your ventilation system should be tailored to your particular grow room, and should function according to the differing needs throughout the year. This may sound daunting, but it really isn’t that difficult.

Below we’re going to go through the reasons you need proper ventilation, how to set up the right system for your situation, and some tips on buying the right things without breaking the bank.

Benifits of Grow Room Ventilation

There are several reasons why grow rooms need good ventilation. Outside, plants are in the midst of natural breezes, sunshine, changes in temperature, natural evaporation, and precipitation – rain and/or snow. Some of these conditions can be a strain on the plant, and indoor growing removes that strain. Some of these conditions also help the plant though, and proper ventilation (along with appropriate lighting and space) will provide these vital elements to your grow room.

Ventilation comes in two main parts: the intake, and the extraction. Both are important to your indoor grow room conditions, and each of them needs to work in balance with the other.

So what will the right system do?

Control Heat

As well as the ambient temperatures in your house, the grow lights you use will also add a lot of heat. A few degrees might not feel very different to a human being, but to a plant it can mean a huge difference in moisture loss, crop volume, and overall health. The ventilation system removes excess heat.

Control Wind

A little breeze can toughen up plants, but it can also stress them in the process. A grow room situation removes the heavy winds, but it also removes the lighter ones that can cause a plant to toughen up stems – and tougher stems can bear more fruit without breaking.


Some humidity is good for plants of course, though the amount varies from species to species. Plants emit water of their own, too, as part of a healthy circuit of water up from the nutrient-rich roots to the shoots and leaves. But this humidity can build up around them in an enclosed space. Too much of it and plant diseases can develop, pests can move in on weakened plants, and mould and mildew can become a real problem. The right ventilation system will remove enough of this humidity to prevent these issues, but not so much that it endangers the health of your plants.

C02 Management

Plants need CO2 like human beings need oxygen. They absorb it through the daylight hours and it helps to fuel their nutrient cycle. A sealed grow room (or tent) can mean a steady depletion of CO2 and subsequent slowing of growth and productivity – basically it starves the plant of needed nutrition. Bringing in fresh air replenished the CO2 levels and allows the plant to continue its regular cycle – producing better growth and yields.


Many pests do well in stagnant, humid conditions. Such places are favourite spots for the laying of eggs and the growth of mould and mildew. A dry topsoil layer discourages the laying of eggs and turns off pests like spider mites and fungus gnats. Even if such pests are present, controlled conditions can slow the growth cycle and give plants more of a fighting chance against them. A balanced ventilation system is a good defensive measure against these issues.

Buying a Ventilation System

If you are going to go to the cost of setting up a grow room (or tent), it doesn’t make sense to stop short of the line and spend your money on a system that starves your plants, reduces yields, or encourages pest infestations. Finish strong with the right ventilation system and the value of the money you spend will increase – as will your enjoyment when you bring in those big, satisfying yields.

You can buy everything you need to control your grow room environment on our website here.

How to Ventilate Your Grow Room

There are two types of fans you’ll need – think of them as the two halves of a full system, that need to be in balance for the whole system to work.

1. Oscillating Fans

Oscillating fans are not expensive, and give great value for the money spent on them. The constantly move air around the room, keeping all areas in and around each plant’s growing space well-ventilated.

They can easily be moved from one location to another, so most people experiment a little with where they are most effective in a particular grow room configuration, or with particular plant species and placement. It isn’t too complex though – simply make sure that the air flow reaches all areas of the room. This is often best achieved by using more than one fan, especially in larger rooms or among denser plant types.

A word of caution though: Don’t aim the fans directly at your plants. This can cause ‘wind burn,’ an unhealthy drying out of the plant tissue, causing damage and stress to the afflicted plant.

Once you have decided on your oscillating fan needs, it is time to turn attention to the extractor fan part of the system.

2. Air Extractor Fans

Extractor fans pull old air out of the growing room, which creates vacuum pressure which pulls in fresh air. This fresh air, as mentioned above, is vital for supplying your plants with enough CO2 for their nutritional system needs.

The goal is to replace the air in the grow room or tent, once every minute or so.

That means that it is relatively easy to figure out what size fan you need for a certain size of room. Take the volume moved by the fan (this will be listed in the product information for the fan – we’ll get into it in a bit more detail below) and compare it to the volume of the grow room. The fan should move roughly the same amount of air in a minute that the room can hold. As long as it is moving that amount of air, and the oscillating fans are circulating the air within the room, you can be confident that you are providing your plants with what they need to thrive.

A little tip for new growers: Set up your fans and light systems before adding any plants to the room – that way you won’t have to work around them or risk damaging them.

NOTE: Understanding Fan Strength

Fans are given a rating based on how many cubic feet of air they move in a minute. This is the CFM rating (Cubic Feet per Minute).

Before you can choose the right CFM level, you’ll need to know the volume of your grow room or tent, and the exhaust efficiency.

Measure the length, width and height of your grow room. Multiply them together (L x W x H). If your room is an irregular shape, then figure out the volume of each portion of it separately, then add them together. Many grow tents have the volume listed in the product information.

Note this number – you’ll need it later.

Next you’ll need to determine the efficiency drop. This is the loss of fan efficiency due to the resistance of filters, and in some cases, the volume of the room. The length of duct between the fan and the filter is also a factor. Don’t panic! Here is a good rule of thumb (well, two rules of thumb!): The first is, take the volume of the room and multiply it by 125%. Use this as your room volume. The second is that, if you have a long duct path, multiply it by three; a short duct path, and only multiply it by two.

So, it looks like this:

(Volume of room x 125%) x (2 or 3, depending on duct length) = needed CFM

Let’s plug in some easy numbers as an example. Say your grow room volume is 100 cubic feet, and your duct length between the fan and the filter is short. Multiply the grow room volume by 125%, then by 2, and you have your needed CFM. In this case, that’s 125 x 2 = 250.

So for that example, you’d need a fan with a CFM of at least 250 (but not a huge amount higher, or you risk over-drying the room).

Intake Types (Passive vs Active)

As mentioned above, pulling air out of the grow room will suck fresh air into it (this is known as passive intake), but sometimes more help is needed to ensure a steady, easy flow – in these cases you might want to consider a, active intake system, one in which air is also pushed into the room by an intake fan.

A passive intake system needs an intake hole at least three or four times larger than the exhaust hole. This aids in easy flow and helps to prevent over-working your fan. Using more than one intake hole can also make up this total, and can help even out the fresh air when ventilating rooms of irregular shape.

An active intake system blows air in with a fan. This reduces the workload on the extractor fan(s) and you’ll be fine with an intake hole the same size as the exhaust hole.


Plants need humidity for proper growth, but too much of it can cause disease, aid in pest infestation, and can hamper growth and yield volumes and quality. Part of a healthy indoor grow room requires constant monitoring of humidity levels.

The leaves of plants will give off their own humidity through a process known as transpiration. This loss of moisture from the ends of the branches of a plant causes suction from the roots and lower portions of the structure, drawing up new moisture that is rich in nutrients to replenish the plant.

If a plant dries out, this process stalls and growth ceases – sometimes to a fatal degree. If ambient humidity is too high, evaporation ceases and the process is stalled from the top end, causing similar end results.

Adjusting humidity is, however, quite simple. To lower it, vent humid air out of the room and take in dryer air through the intake vents. If the outside air is also very humid in your area, you may require a dehumidifier to do the job. To raise humidity, slow the exhaust system temporarily to allow the humidity given off by transpiration to build up a little. You may even want to seal up the grow room for a temporary period to allow humidity to increase.

Monitor each situation closely, as humidity can change quite quickly, and you won’t want to over-adjust in either direction.

Some species of plants, and larger plants in general, need more humidity, so you may need to adjust the grow room conditions as your plants move through their growth cycles.

CO2 (It’s a fine balance)

In some cases, you may want to increase CO2 levels in your grow room by injecting more CO2 artificially. This is similar to giving a human being oxygen when the person is injured or needs to recover from a period of high exertion.  In a grow room situation, however, there are some factors to consider.

First of all, the level of CO2 necessary to benefit plants is dangerous for human beings. CO2 leaking from the augmented grow room could cause health problems in your home.

Secondly, your grow room will need to be sealed. CO2 injection needs very high levels to be effective, and that concentration will not be reached in a ventilated grow room, even if the fans are turned off. In addition to this, you’ll want bright grow lights to enable your plants to take full advantage of the added CO2.

In most cases, CO2 injection is not necessary for an otherwise optimised grow room setup.


Below are some frequently asked questions around grow rooms and grow room ventilation:

How large should my fan be?

You will need to calculate the CFM of your room using the formula we explained in the article above. This is not difficult to do, and can mean the difference between strong success, or total failure. A few inexpensive oscillating fans will also make your ventilation system more effective.

Does my bulb size matter compared to the fan?

You should get at least a 6-inch diameter fan, as this is the usual diameter of the light hood’s opening. It is a good idea to measure first, as they are also available in 4-inch and 8-inch sizes.

How do I know which type of fan to choose?

There is a wide variety of fans out there. Look for an in-line duct fan with a CFM higher than your calculated need for your grow room (see above article). Choose a make and model that fits with your budget and has good reviews. Check whether the fan comes with a filter included, or if it is an additional purchase and factor that into the cost.

What is Negative Pressure?

When the exhaust (out take) fan pulls air from the room, it creates a vacuum within the room. That vacuum is negative pressure. Air from outside the room rushes in to even out the pressure.

What’s the best type of ducting?

For most systems, the best choice is flexible aluminium. It is not expensive and is by far the easiest to install. Other options include heavy duty rectangular ducting or insulated ducting. The key factor is size – the smaller the duct size, the greater the air resistance. Bigger ducts are better for longer distances and to reduce the workload on fans.

Can I make my ducting more efficient?

There are a few things that can improve the performance of your flexible aluminium ducting. The first is to smooth out the curves and corners as much as possible, and then to smooth out the wrinkles in the tube itself. The shorter the length, and the fewer the curves, the lower the resistance.

What size intake fan do I need?

If you are using a passive intake system, you don’t need an intake fan. If you want an active intake system however, you should choose a fan that is the same size as your out take (exhaust) fan.

You can shop a range of Hydroponic supplies here online at Acorn Horticulture, including a fantastic range of propagation and grow tents.