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Table of contents
What is Defoliation?
To make it simple, defoliation is the process of strategically removing fan leaves to increase light penetration and air flow. Defoliating cannabis plants is a debated topic in the growing community, although most would agree it is a beneficial process that can aid in growing a healthier plant overall and a bigger yield. Even if you plan to grow outdoors, some defoliation can help combat pests, high humidity, and more.
You may be wondering why growers defoliate their cannabis plants considering these are natural plants that grow in the wild with no human intervention whatsoever, and they do quite well. In nature, cannabis plants use their foliage to store nutrients for stressful situations such as pest infestations, droughts, nutrient shortages, and more.
However, in an indoor setting, many of these stressful factors are essentially non-existent. Indoor cannabis plants are grown in controlled environments with near-perfect temperature, humidity, and light intensity, with a steady schedule of nutrients. This therefore makes the extra foliage not a necessity, and more of a challenge in most cases. It will only make it harder to control humidity, decrease light penetration, and you might find it difficult to move the plants around for regular checks if there’s so much foliage.
Benefits of Defoliating Cannabis
Increased Light Penetration
Light is one of the most important factors to successfully grow cannabis (and every other plant). Without light, the plant cannot photosynthesize, meaning it will not produce the energy it needs to grow. Light becomes even more important during the flowering phase. Without defoliation, there will surely be multiple bud sites that are not getting the appropriate amount of light to reach its full potential due to large fan leaves blocking light from above. Strategically removing these leaves will allow more light to penetrate through the canopy and reach these lower areas. If you have grown cannabis before and did not defoliate, you likely have had experience with “popcorn buds” or “larf”. Defoliating along with careful and thought out plant training will ensure great results.
Improved Airflow
Defoliating will only help this airflow reach places that it otherwise wouldn’t if the plant is incredibly bushy with leaves on top of leaves. Constant airflow is needed throughout the entire growing process. This is much easier in an outdoor setting considering the wind just does it all for you. However, indoor setups will require one or multiple fans to produce constant airflow. This aids in preventing pests as well as easier control of temperature and humidity. Stagnant branches will also be much more frail and easier to snap. The constant yet gentle movement strengthens the branches, so they can hold up all the (hopefully) massive buds that you’ve grown.
Reduces Risk of Pests
One thing I’m sure all gardeners can agree on is that a pest infestation is one of the worst things that can happen. It can ruin an entire harvest, making the gardener start all over again. Defoliating can reduce the risk of an infestation and overall increase the likelihood of harvesting a good end product. Cutting off leaves, especially near the bottom of the plant close to the soil, is all it really takes. Having as little foliage as possible near the soil will drastically reduce the chance of little critters crawling up onto the plant and eating your hard-earned work.
Limited Space (Indoors)
Indoor growers know all too well the challenge of managing the limited space they have. Every foot counts in an indoor setting, and not defoliating can decrease the amount of room you have available. Some fan leaves can get huge! If you don’t think the leaf is worth keeping due to receiving little light or blocking another bud site from getting the light it needs, then snip it! If you grow your cannabis in a tent, you’ll no doubt see some fan leaves completely against the tent walls, usually contorting. We would recommend just cutting these off, as it’s likely getting very little light and may even develop mold or mildew due to humidity pockets between the leaf and the wall.
How to Defoliate Cannabis
Defoliating will induce stress on your cannabis plant, so it is recommended to only defoliate a healthy and happy plant. Defoliating a stressed or deficient plant may only do more harm than good, and they may not recover like you hoped.
Outdoor Defoliation
Outdoor cannabis plants will not need nearly as much defoliation as an indoor plant. As mentioned at the beginning of this article, cannabis plants use their leaves to store nutrients and aid in photosynthesis. As outdoor plants are exposed to much harsher and inconsistent environmental factors, leaving more foliage would be beneficial. For outdoor plants, we recommend defoliating the lower 30% of the plant to reduce the risk of pests, and possibly some other areas if the strain is especially bushy. Unlike growing indoors with lights, outdoor plants reap the benefit of the sun constantly changing positions, enabling light to penetrate through the majority of the canopy, even if it has a lot of foliage.
Indoor Defoliation
Indoor growers will find that defoliating is much more important in their setting. As mentioned previously, if you believe a fan leaf is not contributing to the growth of the plant or is blocking light to another bud site, then snip it off! Cut off most, if not all, of the foliage from the bottom 30% of the plant. Some leaves may show signs of deficiency due to little exposure to light, and we would recommend removing these as well.
Don’t be afraid to be a little aggressive with your cannabis plants. They are weeds after all and will bounce back better than you may think after being stressed. Some growers remove almost every fan leaf throughout the plant and still manage to produce great results. Others defoliate very little and yet they also have great results. It’s really all about finding what is best for you and the setup you have. Here at The HighWay, we like to go more towards the middle ground of defoliation, strategically removing leaves to improve overall health, but still leaving some foliage to ensure that no amount of light is being wasted.
When Should I Defoliate a Cannabis Plant?
Depending on different training techniques that you might be using, your defoliation schedule may be different from others. To make it simple, we will share our general recommendations that will likely apply to most home growers.
Vegetative Phase
In the vegetative phase, it is recommended to keep most of the foliage while selectively removing certain leaves that are yellowing/dying, blocking lower nodes, or are within an inch of the soil. The big defoliation comes shortly before the flowering phase, roughly 3-7 days before you plan to flip your light schedule to 12 hours on and 12 hours off.
Goals of pre-flower defoliation:
- 90-100% of the bud sites should have direct exposure to light
- Improve airflow to reduce risk of mold or mildew in flower
- More energy directed towards developing flower
It is recommended to do this at least 2-3 days prior to the flowering phase to allow the plant to recover from the extra stress of a big defoliation. Try not to be concerned if it seems that all that foliage somehow comes right back a week later, because it sure does! Cannabis plants are very vigorous and will grow much of that foliage back in no time. This is why we also do a defoliation 2-3 weeks into the flowering phase!
Flowering Phase
As just mentioned, the foliage will grow back faster than you think. By day 14-21 of flower, it’ll look like you never even did any defoliation! All this new foliage will just be blocking buds from light and impair air flow. You can ultimately just follow the same process as the defoliation you just did 2-3 weeks prior, but be extra gentle as to not damage any buds or cause unnecessary stress. At this point in the plant’s life cycle, too much stress can cause some big problems like hermaphrodites or nanners, which could ruin an entire crop. Be mindful of what you are cutting off and don’t go overboard.
Tips for Cannabis Defoliation
- Use sharp trimming scissors – these trimmers from AC Infinity on Amazon work great!
- Start from the bottom of the plant and go up from there
- Be careful – you don’t want to accidentally cut anything off the plant (or yourself)
- Different strains may handle defoliation better than others – indica strains tend to be hardier and more resilient
Mastering the Art of Defoliating Cannabis
Defoliation is both an art and a science that requires observation, patience, and a little trial and error. By selectively removing leaves, growers can improve light penetration, enhance airflow, and reduce the risk of pests and mold, all while maximizing their plant’s potential. Whether you’re growing indoors with limited space or outdoors under natural conditions, the key is to find the right balance that works for your unique setup and strain. Remember, cannabis is a resilient plant that can thrive with the proper care and attention. With the cannabis defoliation techniques shared here, you’re well on your way to cultivating healthier plants and achieving bigger yields.
Looking to learn more about growing cannabis at home? Check out our Ultimate Beginner’s Guide to Growing Weed for everything you need to know to get started growing your own!
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