While most amateur gardeners can achieve great results growing a couple of plants in containers filled with soil, an NFT cannabis grow seems like a logical next step if you want to increase the scope of your operation.
An NFT cannabis grow uses the hydroponic nutrient film technique (NFT). It is a simple system where a nutrient solution is fed by a pump from a reservoir and onto a sloping tray. A constant shallow stream feeds the roots of plants that are sitting on top of the tray in net pots or rockwool cubes.
Benefits of Nutrient Film Technique
The following benefits apply to any hydroponic system, including a nutrient film technique system:
- faster and more vigorous vegetative growth, bigger plants, and generous yields,
- fertigation is fully automated and requires minimum time,
- no need to buy new soil for every run,
- cleaner grow with less pest issues.
NFT growing also lets you save on water because it’s not drained to waste after every fertigation but runs in a continuous cycle.
Like other forms of hydroponics, an NFT grow system takes advantage of the fact that roots need a lot of oxygen to breathe. In soil—especially when it’s compacted and saturated with water—breathing is tricky, and plants develop more slowly. In a NFT grow, on the other hand, only the lower portion of roots is immersed in water while most of them are above its level and get all the oxygen they need.
Another big advantage of an NFT cannabis grow is that plants get only those nutrients that they need at the moment (of course, if the grower knows what to feed them). There is no buffering and no salt build-up in the root zone because there’s no medium. So, if you have overfed your cannabis or allowed some deficiency, just change the nutrient solution in the reservoir and the plants will react IMMEDIATELY.
Disadvantages of NFT for Cannabis
Certainly, there are some.
It’s always up to you to provide your garden with the correct nutrient formula, and it’s trickier than simply watering your weed that grows in a pot with organic soil, for example. So all hydro methods, and NFT growing in particular, are better suited for those with a few successful cannabis grows behind them.
Also, since an NFT grow system runs on electricity, a power outage can kill your crop in no time. Without a constant supply of fresh water, the roots will simply dry out.
As you can see, these are not major issues. Nothing a little bit of experience and some forethought can’t solve.
What Does an NFT Grow System Consist Of?
The main components for hydroponic nutrient film technique are a tank, a tray, and a pump.
- A tank (reservoir). In most amateur NFT cannabis setups, it’s a kind of a tub sitting below the tray with plants and holding several gallons of water and nutrients.
- A tray. Its size depends on the number of plants it holds. The most convenient way is to place the tray on top of the tank/tub of the same size.
- A submersible pump. Shouldn’t be too powerful, especially if no long tubes are involved and the water needs to be lifted only several inches. A 1 liter-per-minute capacity should be enough.
You may also need some additional equipment. The most important one is a water chiller because an NFT grow requires the temperature of the solution to be somewhere between 18°C and 21°C (65-70°F). Temps colder than that may shock the roots and slow down the growth. At higher temperatures, water retains too little dissolved oxygen.
The importance of dissolved oxygen for an NFT cannabis grow is not so great as for a DWC system for example, because roots are not wholly submerged in water. However, if you want to further boost the effectiveness of your nutrient film technique system, you can install an air stone (connected to a small fish tank air pump) to oxygenate the solution with bubbles.
A Store Bought or a DIY NFT System for Cannabis?
The principle behind an NFT grow system is so simple that you can fashion one out of almost anything. A reservoir can be any big bucket, barrel, or tub, and a tray — a length of a large-diameter PVC plumbing pipe to give just one example. The pump, as we have said, shouldn’t be anything very powerful.
So, if you own a house and have some basic tools, odds are that you also have all the necessary materials lying around to make a primitive but working NFT cannabis system. And what you don’t have, you can buy cheap in a local store.
Having said that, today’s market offers enough ready built solutions that are compact, efficient, and have many small but important aspects of cannabis growing taken care of. Remember: for your first NFT cannabis grow, you’ll need all the help you can get, and it’s nice to have some questions addressed and answered beforehand.
How to Set Up and Adjust an NFT Grow System
The details will certainly vary depending on a setup, so we’ll only talk about general principles.
First comes the reservoir. It should conveniently fit into your grow tent and provide easy access for when you want to change the solution. For cultivating just a couple of plants, it should hold at least some 6 gallons (20 liters). Don’t forget that the material of the reservoir (and the rest of the parts) should be opaque and completely sheltered from light — otherwise you’ll get algae (nasty green slime) which can clog the tubing.
The tray is basically another tub, but a very shallow one (just from a couple of inches to several inches deep, depending on whether you’ll use net pots or rockwool cubes). The best place for it is on top of the reservoir—in this case it also plays the role of a cover for the reservoir.
In store-bought NFT kits, when you put the tray on top of the reservoir, the former clicks in place at a correct angle (about 1 degree), so that water/solution can flow naturally from one end of the tray to the other. If you assemble a home-made nutrient film technique system, play around with different angles until you’re sure that water flows freely and there are no puddles anywhere.
How To Grow Marijuana Hydroponically
The next important thing is an even flow of nutrient solution over the entire tray. To achieve this, you’ll need a spreader mat—absorbent material, such as polypropylene or polyester fleece sold in small rolls. If you need to use several strips, make sure they overlap. The roots.of cannabis will spread along the spreader mat, creating a ‘mat’ of their own.
A small pump is submersed in the tank. A piece of tube attached to it is fed to the higher end of the tray. Choose a pump that has a flow adjuster—this way you can precisely control how much water your weed plants will get.
Now take a cover (again, it should be opaque) and cut the needed number of holes/spacings in it—one for each plant. These holes will be round for net pots and square for rockwool cubes. Put the cover in place, and now it’s ready for your seedlings or rooted clones to be put in it. Don’t forget to cover the rockwool cubes from light to suppress the growth of algae.
Make sure to run the system without weed plants first, so that you know that everything works fine and you won’t kill your crops.
Final Thoughts on NFT Cannabis Grow
Hydroponic nutrient film technique efficiently uses air, water, and fertilizers. This both allows you to get outstanding results come harvest and saves a lot of time once your NFT cannabis grow is all set up and dialed in.
If you already are a skilled grower and know exactly how cannabis grows and what it needs, the use of a nutrient film technique system will take you on the next level.
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