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Pruning Cannabis: Why, When, and How to Prune

Mike Wilson
Mike Wilson
Cover Photo 3

Pruning marijuana plants is one of the essential steps to achieving higher yields, both indoors or outdoors. Very simple techniques can be used that generally consist of cutting the top of a plant in order to promote more lateral growth. In this post, we will discuss pruning, both apical pruning or “topping” as well as FIM pruning or “fiming”.

In addition, we are going to teach you various tricks and share the experience of accomplished gardeners who teach us their best ways of pruning and also explain when to prune and why to prune.  Pruning is also a cultivation technique that is frequently used to control and guide the growth of marijuana plants. In other words, pruning consists of cutting one or several growth buds at a certain distance from the apex (or tip of the branch).

Pruning cannabis can be very useful when we need our plants not to grow too tall. Instead, they will acquire a greater development of the latral branchees. When done properly, the cannabis pruning technique does not have to mean a loss of harvest, achieving the same or even better results than without pruning.

Why should we prune the cannabis plant?

By cutting the main apex of the marijuana, the auxins and other hormones involved in growth are distributed through the rest of the secondary branches. This achieves a greater growth of these branches to the detriment of the main stem. In terrace or guerrilla cultivation, it is sometimes necessary to control the growth in height of the plants so that they go unnoticed by prying eyes. It is in these circumstances when experienced growers appreciate the discovery of this ancient cultivation technique.

When we grow indoors in small spaces, cannabis pruning is also extremely useful, if not to say, essential. For example, in small grow spaceds with enough height, the side branches can be pruned to grow more plants with fewer side branches but with a larger central bud.


Kabrales with apical pruning to control the size in a small indoor growing area.

Because there is no limitation in height, we do not run the risk of the bud being very close to the focus and burning due to excess heat. On the contrary, if we grow in a space that is limited in height, a pruning of the central stem will give us shorter plants that are more branched and compact.

Experienced gardeners believe that the fruits of the plant require a lot of effort to grow to the desired point. So, many times, when we prune marijuana, what we do is eliminate other parts of the plant so that it doesn’t have to allocate energy to these area and can focus all of its efforts on creating a huge central bud. Pruning can also have other purposes as we have indicated at the beginning of this guide.

When can we prune weed plants?

It is advisable to prune after the plants have developed the third pair of leaves, or third internode. This usually happens between 20 and 30 days of growth. It is not advisable to prune before this because the plant will not yet be prepared to cope with this stress. It is very important to always prune before the start of flowering so that the plants have time to assimilate and develop the secondary branches as much as possible. After pruning, growth hormones such as auxins are distributed to the secondary areas of the plant, giving rise to greater growth of the lateral shoots and lower areas.

If you are a grower who likes to transplant your weed plants and parts from small pots (like the classic 500cc plastic cups) then we recommend the following. Do not do a pruning in the first 20 or 30 days of life. Wait until your plant is at least 45 days old, transplant it to its new pot and then, after about 2 weeks, carry out the pruning. It may seem a bit difficult to you, but it is not. Quite contrary to what you are thinking, you are going to help the plant handle the stress a little faster and develop optimally, faster, and more effectively.

What kind of prunings are there?

Cannabis pruning, along with the cutting process, are two of the most delicate techniques of advanced marijuana cultivation. Sooner or later, every self-respecting grower will have to face these two growing techniques. Pruning growing marijuana can translate into a multiplication of the harvest.

BRUCE BANNER pruning outdoor

This Bruce Banner #3 from Blimburn Seeds. Pruning was used to stimulate the central buds.

Pruning in marijuana crops is not something new, nor is it an innovative technique that has emerged in the new age of cannabis cultivation. On the contrary, pruning marijuana plants at the optimal moment should be part of every expert grower’s cannabis cultivation manual.

When talking about types of pruning for marijuana, almost everyone thinks of the most well-known types of pruning: apical and FIM pruning. Pruning is a type of action that alters the natural pattern of marijuana growth with the aim of increasing production.

Apical Pruning

Apical marijuana may seem extreme at first, but don’t be afraid to do it. To prune marijuana apically, the central tip of the marijuana must be cut. In this way, you get a fork in the center of the trunk of the plant in the form of a Greek Y. This encourages the plant to stop vertical growth, sending more energy to the side branches for growth. It is perfect if what we want is to obtain branched plants with low height. Top pruning is recommended in situations where you don’t want your plants to grow vertically.

apical pruning purple star killer 2

Purple Star Killer with apical pruning

This apical technique for pruning marijuana is usually done with a Scrog because having more vertical branches helps make this technique suitable. It is an ideal marijuana pruning technique if we plant long-flowering plants and outdoors it will also be useful to control the height of the plants.

FIM pruning

This marijuana pruning technique is similar to topping. This is due to the fact that in both techniques, it is necessary to cut the upper shoot. However, there are differences because instead of extracting the entire shoot, we will cut 80% of it. In this way, we leave a part of the bud and that hole that we had to cover when doing apical pruning does not appear.

fim prunning grandaddy purple

Granddaddy Purple with fim pruning

The goal of this marijuana pruning procedure is to get 4 to 6 new main buds at the top of the tip. It is the easiest way to increase the production of marijuana with a simple incision. It is important to emphasize that you do not need to cut the entire shoot because otherwise, we will be topping. The procedure of FIM pruning for marijuana is very useful for increasing the production of cuttings in the mother plants. Thus, when we plant a cutting to get a new mother, we can FIM it and obtain the greatest number of shoots possible from the beginning of the crop.

How to do FIM pruning?

The first step to apical weed will be to find the third node of the plant. Next, you will have to make a cut so that you extract 80% of the central bud, leaving 20% ​​of the new knot. The next step to pruning marijuana will be to wait for the plant to recover. If the plant has long growth, it is possible to do this technique several times. If at the time of pruning the marijuana you notice that the concentration of buds begins to appear in the lateral areas of the plant, you can extract a leaf or branch to concentrate the production in the central buds.


How to do Apical pruning?

First, it is important to do the pruning in the vegetative growth phase so that the plant can grow in width. The cut must be clean in addition to leaving enough space between the upper pair of leaves and the lower pair of leaves. It is highly recommended to use a healing agent to cover the cut so that no particles that could contaminate the plant are introduced. This can be repeated for the plant to have the greatest number of branches and grow as wide as possible with a greater proliferation of lateral buds.

poda apical 1

What are the benefits of pruning cannabis plants?

With the pruning of the cannabis plant, different effects are achieved, depending on the pruning applied. For example, apical pruning causes the plant to grow wider than it is tall which can be very useful when there is no more vertical space. You can also get the light to penetrate other areas of the plant that it did not reach before. With this, you will be able to cultivate favoring the parts of the marijuana plant that were found in a dark area.

We emphasize that it is always good to take into account what type of cannabis plants you are growing as it is not the same to prune plants that are usually more sativa than indica. Instead, more sativa strains of marijuana have more distant internodes and, ultimately, more upright growth. As they are pruned more, they tend to exponentially strengthen their lateral branches and we control their natural branching.

On the other hand, the mostly Indica varieties tend to have shorter internodes and more lateral growth. For this reason, when pruning, they will extend much more towards the sides and if the central bud is going to be produced, it is much more powerful and tends to thicken and become extra dense.

In short, the most notorious benefits of pruning marijuana reside precisely in the fact that we can mold the plant towards a specific purpose. Normally, in the case of marijuana, the main goal is to obtain a higher production of buds with a greater amount of resin (by receiving more lighting and more nutrients, resin production increases greatly) and better organoleptic properties (it can develop more and better terpenes).

BE CAREFUL When you prune your plants

An important fact to keep in mind when pruning our beloved plants is that from each sectioned branch, we will obtain two new “Y” shaped shoots. This will determine the space that each plant will require within the growing area. A plant that has had its main shoot removed will tend to grow much more in width than in height. Pruning cuts should always be made at an angle of 45 degrees to avoid moisture and condensation on the surface where the wound has occurred.

An excess of moisture near the open wound on the stem can lead to the appearance of infections and fungi which can harm the health of the plants. In your nearest grow shop or grow store, you can get a magnificent sealing paste for vegetable wounds. You can also apply the dry substrate that you use to grow which sticks and helps to heal thanks to the humidity of the pruned area.

Using very clean and sharp scissors, a cutter, or a scalpel is essential to preserve the health of the plants. Hygiene in cannabis cultivation is another determining factor which will make the difference between a mediocre harvest and a gourmet-quality professional harvest. In a dirty environment, the probability of suffering an attack by fungi or other pathogenic organisms is multiplied exponentially. Finally, we just want to tell you that all of our photo-dependent genetics such as our feminized, regular, or fast version cannabis seeds deliver great plants that are perfect for you to prune and practice until you achieve the level and performance you so desire. Keep in mind that our Blimburn online store has more than 800 different weed varieties from classic strains of the old school and also from the new generation. See you on the next blog where you can find more information and cannabis education because we want you to be the best weed grower you can be so that you can achieve the best marijuana that cheers your spirits.

Strains featured in this article:

Mike Wilson

Mike Wilson is a passionate cannabis cultivator with over a decade of experience in the California cannabis industry. Born and raised in the heart of the West Coast, Mike has dedicated his life to honing his skills as a cultivator, becoming a true master of the plant. His love for cannabis and profound knowledge of its cultivation have led him to explore every facet of this captivating plant, from classic strains to the latest trends in cultivation and advanced techniques.

With a unique perspective on cannabis culture and a focus on sustainability and quality, Mike generously shares his valuable tips and tricks on this platform. Through his posts, he will guide you on the exciting journey of cannabis cultivation, providing expert insights and practical experiences to help you achieve success in your own cultivation endeavors. Join Mike on his journey through the world of cannabis and discover how to cultivate responsibly and achieve exceptional harvests. Become part of his community and unlock the secrets of a true cannabis master!

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