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Are Your Big Cannabis Plants Bothering You?

Cannabis Plants 1

Robust, big cannabis plants are undeniably every grower’s dream! Plus, an overflowing supply of weed buds with every harvest! But oftentimes, those dreams turn into high-maintenance nightmares. We are talking about the times when your big cannabis plants grow into excessive heights! This is an issue that a lot of indoor growers have reported. While it isn’t common for outdoor gardens due to the unlimited ceiling space, an indoor grow room can run into a bunch of problems. Having excessively big cannabis plants, for example.

We are not saying that big cannabis plants are a threat! Many people out there would actually invite this feature as it would mean thicker and chunkier buds! However, cannabis plants do have an optimal height that is enough to support the growing buds of your crop. Taking all this into consideration, are your cannabis plants too big?

Why Do I Have Extremely Big Cannabis Plants?

Depending on the marijuana seeds that you plant and cultivate, your tiny babies can grow up to an astounding 15 to 18 feet in height! This can prove to be quite an issue. Most especially since the average indoor grow room will only house a ceiling that is around 8 to 10 feet off the floor. 

Not only does this run the risk of your cannabis colas bump into the ceiling. It also destabilizes the whole weight of the plant! Without a properly installed support system, these can easily fall and topple over. 

In addition to this, keep in mind that you are going to have some grow lights and ceiling fans installed into your setup! Having the top-most colas exposed to the lighting systems at a very near distance will undoubtedly cause some sort of heat stress or even burning. Keep in mind that this holds true even for LED lighting panels, which give off cool spectrums of UV light. 


Much like all the other unnatural behaviors of cannabis plants, their growth into tall heights is mainly caused by the improper (or excessive) maintenance of their environmental conditions. Don’t take this the wrong way, though! Having very big cannabis plants is often a sign that you are doing great in providing a comfortable environment and growing space for them to develop. 

But this growth may often go overboard if left unchecked. Here are the main factors that may cause the excessively big cannabis plants in your marijuana gardens:


Tall cannabis plants are often the result of changes in the growing area’s temperature. The growth of cannabis plants during their vegetative and flowering stages will usually take place with a fixed temperature pattern influenced by the lighting systems. One behavior that they display is that when the temperatures in their growing areas drop due to having the lights off, the branches and stems significantly start expanding and stretching. 

If the hours of lighting are kept at shorter timeframes than the one hours of darkness for long periods, then the cannabis plants may very well start growing up to taller heights. 

Air Flow:

Without the benefit of natural winds in an indoor garden, the stems and branches of indoor plants will tend to be a lot more flimsy and weak. This, in turn, can affect the support that the plant has for big plants. As it may not be able to hold up the buds as well as the heavyweight of excessively big crops, we can see why a proper ventilation system is important for keeping the development of your crops in check.

The presence of circulating air and CO2 in your gardens tends to “loosen” the cell structures in your cannabis plants. As a direct result, the plants will shift their cell development into strengthening the cell walls instead of stretching the cannabis stems and branches. In turn, they would not grow into excessively big cannabis plants. 

Lighting Systems:

The lighting of your indoor cannabis gardens will also play a big part in the height and size that they can reach. As we have said above, cannabis plants’ stems and branches tend to stretch and grow longer during the hours where they are not exposed to lighting systems. If you are operating a lighting system that gives off insufficient UV spectrums, then the plant hormones will typically respond by causing a faster development rate of elongation.

This also holds true in growing spaces that are not properly spaced out. Because the thick foliage of leaves may block the entrance of light from reaching the bottom leaves and parts of the crops, their initial reaction would be to cause a growth spurt in their heights to make up for the insufficient lighting given to them. 


Lastly, the genetics and marijuana strains that you will be making use of are also an inherent factor in deciding how tall your plants grow. It is common knowledge for growers that Sativa strains are capable of developing into tall and big cannabis plants. 

As their average heights measure around 10 to 15 feet, it is important for indoor growers to study the growth patterns of these strains and do what they can to keep them as regulated as possible. Additionally, leaving too much space in between your plants can cause the expansion of their leaves and branches.

What To Do If Your Big Cannabis Plants Grow Out Of Control

The optimal heights of cannabis plants will usually depend on which strains that you grow. While indica cannabis plants tend to grow up to around 2 to 5 feet in height, Sativa strains can reach anywhere from 6 to 15 feet! Those with ruderalis genetics (autoflowering versions), on the other hand, usually average around 1 to 3 feet in height. 

There are several things that you can do to mitigate the height of any big cannabis plants that exceed their optimal size. Plants that are too big may be inconvenient and troublesome to maintain. Here are the methods of controlling their height:


Topping your cannabis plants is usually done to increase your yields. However, it is also a regulatory process that makes sure your cannabis plants stay at a height that is fit for your gardens. Topping basically consists of cutting off the topmost cola of your plants. As this halts the apical dominance or vertical elongation of your plants and instead focuses its energy on the development of a thicker and more robust structure, topping is a great way of keeping their heights under control.

But when exactly do you need to top? Well, since it will practically be working for two purposes, growers should start topping their cannabis plants during the last weeks of the vegetative stage. Right before they start flowering, the added number of main colas will distract the plant from developing further height.


There are a lot of training techniques (such as Low-Stress Training or LST) that also aim to increase the yields of cannabis plants through controlled degrees of stress. With the use of methods like the Screen of Green (or ScrOG) to help manipulate the growth patterns of the crops, they will start stretching horizontally instead of vertically. Training techniques will usually involve tying down the branches of cannabis plants in a horizontal direction to promote wider growth and more buds.

Incidentally, these can also be very useful in controlling the heights of your plants! As they will aim to produce a much more even canopy atop, the risk of having them grow taller and taller is virtually eliminated.   


In the above section, we explained the different environmental factors that can cause the excessive growth of your cannabis plants’ heights. By controlling these factors, you can avoid having them grow into uncontrollable heights! This is good for both your plants and your setup as tall plants tend to fall over or bump into the installed equipment in your ceilings.

For one, make sure that you have a proper air circulation system in place. The constant flow of active air will cause the cannabis plants to develop stronger cell walls as opposed to growing taller. Also, try increasing the hours of light that your cannabis plants get. With the decreased amount of time spent with lights turned off, your plants will focus more on bud production. Rather than growing vertically. 

Furthermore, humidity fluctuations can cause a plethora of negative effects if you are not careful. Excess water vapor in the air can be hard to control, and big cannabis plants release a lot more of this than smaller plants. To keep molds and other diseases away from your plants, keep the humidity levels at around 50% to 60%.  


You can make things a whole lot easier for yourself if you start with the right genetics. Autoflowering and indica strains are much more compact and grow a lot shorter than Sativa strains. Picking an appropriate strain that would be a perfect fit for your gardens is crucial! It can solve the height problems of your cannabis plants well before having to actually experience them!

With that being said, you can always go for Sativa strains if that is your go-to. Growing them under their desired conditions while also keeping an eye on their apical dominance characteristic will help you avoid having to worry about excessively big marijuana plants.

Big Cannabis Plants: A Blessing Or A Curse

Having extremely tall cannabis plants can either be a blessing or a curse to growers! While it is something that a lot of people strive for. While it achieves bigger yields, it can also be bothersome to regulate and maintain. 

There is an optimal height for each marijuana strain! Overdoing it can definitely cause more damage to your setup. As such, it is always recommended to keep the cannabis plants’ heights under control!

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