root pruning cannabis

The Advantages Of Air Pruning Cannabis

Air pruning has become huge in gardening. The good news is cannabis is definitely suitable for air pruning. Fruiting and flowering plants can grow bigger, stronger and faster with air pruning. In this blog, we show you how to work a little air pruning magic in the cannabis garden.



Air pruning is what happens naturally when a root tip comes in contact with air. Instead of probing further the tip dies, and more root branches grow to develop a fibrous mass. In conventional plastic pots cannabis plants, roots wrap themselves around the tiny gap between the medium and the plastic interior.

The roots grow long and continue searching for new fertile substrate instead of branching off. Roots will even burst through and cling to the holes at the bottom of plastic pots. They just keep on growing unless they are air pruned.


Air pruning will help you crop a heavier harvest. By encouraging a dense root mass in a well-draining oxygenated medium, your cannabis plants will explode with buds. Your plants will be able to handle larger volumes of nutrient solution and you won’t have to worry about root rot.

Best of all, by air pruning, you are really making the most of your medium. This is especially important if you have invested in premium pre-fertilised substrates or created your own super soil. Air pruned plants will access more of the nutrient-rich medium.

Instead of a few long spaghetti string roots, air pruned cannabis plants develop a root mass like a spiders web throughout the medium. A healthy robust root zone facilitates larger plant growth above ground and fatter flowers come harvest.


The act of air pruning your cannabis can be completely passive in most situations. As outlined, the roots tips die when coming into contact with air and the boost growth elsewhere. All you have to do is make that air available. This is done with air pruning pots — specialised plant pots that are designed for this exact purpose. What this means is that as long as you grow your cannabis in an air pruning pot that is approriatly sized for your cannabis, air pruning will happen automatically.


Today you have four options when it comes to air-pots. The first most expensive choice is the classic flat packed air-pot made of durable plastic and available in a wide range of sizes. Believe it or not, they are still the premium priced product. But they are built to last and great for growing weed trees.

The second choice is a smart pot. But not just any smart pot. You can pick up high-quality fabric smart pots online and even at ordinary garden centres on multipack deals if you shop around. They are definitely far more discreet and easier to carry home than huge plastic containers. Some brand name smart pots are extravagantly expensive and no better than economy smart pots made of the right stuff. Ideally a high-grade geotextile pot with handles. Sizes are impressive these days from 1l to 100l+.

The third pick is a rigid plastic air-pot. These pots are a cheaper alternative to the more expensive originals. They usually cost about half the price. Readymade air pots work just fine and are also available in a wide range of sizes. While they may not look as cool as original air pots they are just as functional.

The fourth alternative is to make your own air pot. But there really is no need too. Homemade pots are just like homemade muffins. Most of the time they suck and everyone is too polite to say so as they choke it down. You owe your cannabis plants better and store bought is always better than homemade.


Indoors, any of the above is a solid choice, no matter what medium you prefer to cultivate your cannabis with. Most smart-pots made of fabric are really best suited to soil and/or coco. Black fabric smart pots are usually available on discount or a reduced price for multiple pots. Smart pots with handles are actually easier to move around than either of the plastic air pots.


Outdoors white geotextile pots are your best bet. They are relatively cheap, although always a little more expensive than the black indoor kind. But you need to pay that little extra to keep the roots cool. And you don’t want the medium drying out too rapidly either. So the reflective white fabric is more advantageous for the outdoor weed farmer. Handles are critically important. You will either be moving your plants to follow the sunlight or to shelter in a rain shower, so buy the kind with handles.

Air-pots are too cumbersome without handles in the extra large sizes that outdoor cannabis grower’s desire. They may be of interest to discreet balcony growers able to manoeuvre 10l air-pots. If you want to grow monster marijuana plant you really need a super-sized smart pot.


Holding on to a mother plant of your favourite strain long term is best accomplished by potting that mother in a large air pot or smart pot. You definitely can’t keep a mother plant in a small pot for long. Non-porous plastic pots are not recommended even if they are quite large.

However, if you find yourself stuck with a root bound mother plant in a plastic pot you can salvage the situation. By removing the bottom two-thirds of the root mass and potting up into a larger container you can save your precious mother plant. It’s a risky move trimming so many roots and there is a significant risk of transplant shock too.

Provided the process goes smoothly the recovery time for the mother plant to re-grow a dense healthy root zone is enough to set you back. Expect at least a couple of weeks delay before you can take more cuttings.


Overall air pruning is a valuable cannabis cultivation technique. In fact, unless you’re already deeply committed to a particular hydroponics system you should at least experiment with air pruning. Soil and coco growers can easily make the switch whether they grow indoors or outdoors.

All you really need to do is upgrade your containers to air pots and/or smart pots and see the results for yourself. Once you find the right kind of air pot or smart pot for your grow show you’ll never go back to plastic pots. Most ordinary decent home growers can grow an impressive air pruned cannabis plant with a 15l air pot or smart pot indoors or outdoors in a warmer climate.

Cannabis plants respond positively to air pruning. It’s worthwhile considering an upgrade to air pots and smart pots. Let’s talk air pruning.

Marijuana pruning, all techniques

Image representing a barber prepared to carry out a pruning to a plant of marijuana

Has it come the time to prune your marijuana plant and you are not sure how to do it? 🙄 Don’t you know if it is the perfect time for pruning cannabis? When is the best time to prune? Don’t worry, no one is born knowing, and luckily this is not difficult to learn.

Pruning of the marijuana is done to gain production, usually many varieties tend to create a large central bud if they are allowed to grow and bloom in their own way. However pruned cannabis can make better use of the distribution of light between all the parts of the plant, producing more buds shaped in secondary branches and even lower.

At this article we will see when and how marijuana should be pruned to get an extra weight in the harvest, starting by seeing the different forms of pruning and their advantages:

🧐 Types of Cannabis Pruning

  1. Apical pruning (upper parts of the plant)
  2. FIM pruning (upper parts of the plant)
  3. Pruning of lower parts or Lollipop (lower parts of the plant)
  4. Root pruning (root zone)

It is necessary to distinguish between prunings that are carried out in the upper parts of the plants and the others. Before we start with it, we have to understand the way the cells responsible for plant growth work, the Auxins, which are always located in the upper sprouts, and once we cut these sprouts these cells move to the next higher parts of the plants. This means that when cannabis is pruned we encourage growth in the other higher parts of the plant.

👾 Apical pruning of cannabis, how is it done?

What is apical pruning? It is the most common technique of pruning cannabis, and doing it is very easy, just cut the top bud at the level of the last knot. This way instead of having a single main end we will have 2, if we do 2 apical pruning we will have 4 main ends, and as many times as we want while we are in the growth period, once in flowering is no longer recommended to make any pruning in the upper parts.

photo of a plant of marijuana with the apical pruning done*

When to start pruning cannabis?

If you want to start as soon as possible, wait at least until the plant has formed 4 knots, that is, 4 pairs of normal leaves, not counting the cotyledons. To continue pruning the marijuana it is necessary to wait to the following main branches begin to grow with strength, when you see that these already have other secondary branches. To go deeper into this method of improving production, I recommend you to read this article that specifically talks about the apical pruning of cannabis step by step.

🎯 FIM pruning in a Cannabis plant

This technique was discovered by chance, F.I.M. is the acronym for “Fuck i missed”, and is what happened to an American grower when he tried to make apical pruning to his marijuana plants. Later he discovered that what seemed to be a mistake had become a great success, since in the bud he had cut began to grow several new branches.

How and when is FIM pruning done?

To do the apical pruning we cut the bud at the height of the last knot, in this case it is necessary to leave between 10% and 20% of the bud. This way the growth is slowed down a bit in that moment, but later the lost time is recovered, since instead of a tip, in that bud will grow 3, 5 or even more shoots.

If we are pruning cannabis to get the maximum weight in harvest, the ideal way is to try FIM pruning at all branches of every cannabis plant, do not be afraid if it is your first time and you are not sure you can get the ideal shoot size to succeed. But, what happens if I do wrong FIM pruning? Well, it depends, if you leave more than 20% of the bud in the cut the most likely is that this same bud continues to grow the same way but with the main leaves cut. If on the other hand you cut more and leave less than 10% you will be doing the typical apical pruning, so don’t be afraid, if you don’t do the FIM correctly nothing bad will happen either.

illustration showing the difference between FIM pruning and apical pruning*

🔥 Low pruning or Lollipop technique

This method of cannabis pruning has several advantages, on one hand we clean the lower parts of the plant, where the light does not arrive well and surely they are going to produce little or nothing, consuming energy and resources that will take advantage better for buds of the higher parts, where the light arrives well.

In indoor crops we also get more ventilation, because by clearing the low areas the air runs better through those parts, avoiding the dangerous bags of moisture that can end up forming fungi that ruin our harvest.

photograph where you can see an indoor cannabis crop with low pruning*

How do I do Low Pruning?

With help of a cutter or a pair of scissors, cut all the leaves and sprouts where there is no light. We will leave the stems clean from the flowerpot until the height where buds begin to be well formed.

If you grow with the “Screen of green” method you can cut everything that is below the net, if you do “Sea of green” the ideal is that you leave only the main tip of each plant, and if you do not use any optimization technique you can use the depth of focus, where you see that the light does not reach you can prune it. Cutting the leaves of cannabis plants is not ideal in many cases, they are like solar panels that catch the light to transform it into energy, they are also the nutrient reserve and, when the substrate does not have the necessary, plants eat those resources. But in this case cutting leaves and sprouts of cannabis is positive, because if the light does not arrive, they subtract more than they add.

When to cut high leaves of cannabis?

First of all you should never cut the healthy leaves of the high parts of the plants, except when these cover excessively the light to other plants. The leaves that are attached to the buds should never be removed, but the large ones in medium height can be cut in the case mentioned above.

🚀 Pruning of Marijuana Roots

The 3 previous pruning techniques are done to gain production at harvest, but root pruning is done more as maintenance. In a normal crop, when the plant grows and the pot becomes small we normally transplant and solve the problem. This cannot always be done with mother plants, especially with “bonsai mothers“, which we try to keep in small pots so that we can have more varieties in less space. In this case what is usually done is a pruning of roots of cannabis plants and being able to use the same pot for a longer time.

How do I prune roots?

First you have to take the plant with its root ball out of the pot. Then, with the help of a cutter, a saw or a knife, we cut a part of the perimeter of the root ball, if it was in a 15 x 15 pot we can remove 3 or 4 centimeters from each side, as you can see in the image below.

image of a mother plant being pruned of roots*

Once we have pruned the root ball we add new soil to the pot, put the plant in, and fill the space with more new nutrient-rich substrate. This way the mother plant creates new roots again, gaining health and vigour until it has again space problems, at which point we will prune the roots back again to our cannabis plant.

⭐ Can I prune autoflowering plants?

The answer is yes, how can you do it, but it’s really not very interesting, because the plant loses some time in recovering the growth rate after a pruning, the time that auxins need to relocate in the plant. Autoflowering plants have such a fast growth cycle that rather than taking advantage of pruning to produce more, you can lose production because of lost development time.

If you want to prune automatic plants for height reasons, in this case you can do apical pruning or FIM, to encourage lateral growth compared to vertical.

✨ Pruning in outdoor crops

Indoors pruning makes more sense than outdoors, this is because indoors the light is fixed above, however outdoors the sun moves, and distributes the light much better to every part of the plants. But that does not mean that pruning in outdoor cultivation is not good, as it can also help to increase yields.

The most productive plants outdoors are those that have the shape of bushes, as round as possible, for which many prunings are needed, first the main tip, after a few days the secondary branches should be pruned, then the following ones, and continue so until plants get the pre-flowers, when we stop pruning the upper parts. Then the lower parts can be cleaned and so when the plant focuses on flowering it will be as ready as possible.

Can all cannabis varieties be pruned?

All varieties can be pruned, but there are some that are more likely than others. Sativas or hybrids with sativa dominance are the best because they tend to branch out more than Indicas. In fact there are indicas that do not really benefit from pruning, they perform better without pruning because they are very columnar and compact, and they concentrate most of the production in the main tip.

⛳ Tips and tricks for pruning cannabis

It is advisable to use a healing product to treat the newly pruned plants. When we cut the stem of the marijuana we are opening a way of access for fungi and other illnesses, so if we cover it we avoid future problems.

Aerial pruning is always done during the vegetative growth phase, both apical pruning and FIM. This is because marijuana creates new shoots during this cycle, but once the flowering begins it stops forming them to focus on creating flowers.

Pruning cannabis during flowering

If you don’t have more options and you are wondering how to prune in bloom, you have to know that the production is not going to improve anymore, but if it is due to space problems and there is no other option than pruning, you can do it

However low pruning can be done during flowering, the best option is to do it just before changing the cycle, but in this case there is no problem if it is done during the flowering phase.

Can I increase production without pruning?

Sure, there are techniques to contain the size of the plants and at the same time get more parts exposed to light. The best way is the L.S.T., which means “Low stress training”, which is something like shaping the plant to your preference without damaging it. What does this method consist of?

It is about folding the tip and the branches to leave them in horizontal position, tie them to the flowerpot with care, and the shoots of these branches and the tip grow vertically in a homogeneous way, taking better advantage of all the space without having to cut anything.

Another good way is Super Cropping, which means crushing the stem carefully, at a distance between 10 and 20 centimeters from the main tip, and bending the tip to approximately 90 degrees, so that it is perpendicular to the focus.

After a few days, when the secondary branches have grown quite a bit, the operation is repeated with these, in order to try to keep all the main branches horizontal, and more or less at the same height.

Drawing representing a marijuana plant with the super cropping technique done*

Do you know any other way to prune cannabis plants? If so, tell us, and if you think this article is interesting please do us a favor and share it.🤨👉

Do you need to prune cannabis plants? ✨ Do you know what FIM pruning is? ✅ Discover the best ways to prune cannabis and shape your plant to your liking.