Defoliation. One of the more controversial subjects in the cannabis cultivation scene, and even more so when looking at autoflowering strains. For the longest time, autoflowering genetics were seen as fragile, low potency, low-yielding options that needed to be treated with supreme care – but the last few years have seen a real shift in the autoflowering market, with the rise of the ‘super auto’ generation.
So, is it okay to defoliate autoflowers? When should you look at implementing defoliation? How does defoliation benefit cannabis growth? How much is too much?
But before we get ahead of ourselves, let’s look at what defoliation actually is, yeah?
What is autoflower defoliation?
Autoflower defoliation is the process of removing excess leaves from your plants. This improves light penetration and air circulation while redirecting the plant’s energy towards bud development. The result is bigger yields and healthier growth. To prevent stress, you should only remove 10-20% of the leaves each time.
Understanding the proper timing, the perfect defoliation ratio, and the right technique to remove fan leaves is essential to maximizing the yield and ensuring you don’t do more harm than good.
By removing leaves from the lower canopy, we can
- Increase the light penetration to the budding sites – especially those on the lower branches. Areas that are shaded by the fan leaves have limited access to light which can slow the production rate of flowers.
- Increase the canopy air exchange – canopy ventilation is an often overlooked aspect of cannabis cultivation (particularly by novice growers). Without decent ventilation, budding sites can be starved of essential levels of oxygen, and the humidity and temperature in the canopy can quickly rise to uncomfortable levels. By removing fan leaves from the lower parts of autoflowering plants, we can allow fresh air to circulate better, and help to keep the temperature/humidity stable.
- Increase bud size/density – removing leaves from the lower canopy and slowly working our way up the plant can help to boost both the bud size and overall flower denseness. By reducing the amount of non-flower plant material, the plant has to support, you increase energy distribution through the emerging flowers.
- Reduce the chances of pest and mold issues – Old, yellowing, decomposing leaves are a hotbed for all sorts of problems, from outbreaks bud rot to pest infestations. By regularly defoliating autoflowers you can ensure that all the leaves are healthy and reduce the chances of any annoying diseases or pests.
- Slow the growth rate in a particular area – When defoliating a certain branch, there will always be at least a slight reduction in growth for a day or two (if not slightly longer). Defoliation is an effective way to gently slow down the growth of a branch that may be overtaking the rest of the plant.
Does defoliation increase yield?
If done correctly yes defoliation will increase yield. The sole purpose of defoliation is to get rid of any dead wood, by this we mean to cut off any dying leaves, leaves that are blocking out sunlight to other areas, or leaves that just aren’t receiving much sunlight. This allows the plant to divert more of its energy to other more useful areas such as its buds.
Remember though that defoliation is not the only tool at your disposal to boost your autoflower yield. There are plenty of other great methods such as LST or ScrOG that also provide increases to your yield with very little stress. Bare in mind that you don’t need to stick with just the one training method, you can also use LST and defoliation together with powerful results.
On the subject of increasing autoflower yields you should also look at other factors that affect your grow such as; pot size, using the best soil for autoflowers, light schedules, nutrients and using the best high yielding autoflower genetics.
This is the most hotly debated aspect of the whole discussion. Ask 10 highly experienced autoflower growers this question and you will likely get at least 5 conflicting answers.
We have done our own experimentation, and over the last few years we reckon we have got a pretty solid defoliation protocol down for autos, no matter if it is an indoor or outdoor crop.
This system is different from how we treat our photoperiod plants and is much less invasive. There are growers out there who like to go full-on with their auto defoliation, but we have found that a set schedule of easy and slow fan leaf removal works best for the vast majority of autoflowering strains.
What we suggest is to remove just a few of the lower leaves in the fourth week, and then again in the second or third week of flower. We never remove more than 1/4 of the leaves at one time, and try to stick to the older, less robust-looking leaves.
Can you remove leaves at other points?
Yes, for sure. If there are leaves that are yellowing or just looking really sad, we go ahead and carefully remove them – especially if they are blocking light penetration from hitting the flowers. Cannabis is a full-sun plant, and will always do best when exposed to the maximum direct light possible.
Yes indeed. Defoliating cannabis can stress a plant, and its even more risky with autoflowers. Any form of plant training comes with a list of positives and negatives, and defoliation is no different.
- The biggest risk associated with autoflower defoliation is shocking the plant. If you are too aggressive and remove large portions of the foliage at once, or just trim off an excessive amount of leaves over a short period of time, then you can see stunted growth and lowered yields as a result. The magic of autoflowering genetics is just how fast they can go all the way from seed to harvest, but with this speed comes less time for the plants to recover from any stunting issues.
- Then there is the danger of excessive defoliation. Each leaf is akin to a solar panel, with them playing the photosynthesis powerhouse role. While fewer leaves can equal bigger, juicier, heavier buds – going overboard can have the opposite effect.
- Older leaves can share mobile nutrients with newer areas of growth as needed. When you defoliate, you run the risk of causing some nutrient deficiency issues.
- All forms of plant stress increase the risk of causing a plant to turn hermie.
How many leaves should you remove during defoliation?
Again, a contentious and highly debated point. A quick google search will offer a bunch of different answers, but from our experience, less is definitely more when it comes to defoliation – and for auto cannabis strains in particular. No more than one-quarter of the total fan leaf count at one time, with less also being totally fine. To stay on the safe side, I normally remove around 15% of the fan leaves and then leave it, see how the plant responds and if no signs of stress are showing in a few days time you can remove a few more.
Schwazzing is one of the more recent evolutions of defoliation and is a pretty drastic and extreme measure to take with any cannabis strain, and definitely with autos. The idea was first introduced into popular cultivation circles by the book ‘Three A Light’ which gives a clear and straightforward path for growers to produce 3 pounds of dried bud per 1000W lighting rig, but to say we are a little skeptical would be putting it lightly.
Schwazzing involves removing all of the fan leaves (and some of the lower branches) in an effort to redirect every last drop of the plants’ life force into flower production. And while some growers have found success with this extreme method, we simply cannot recommend such invasive maneuvers. Sure, if you want to experiment with photoperiod strains then go right ahead! The control you have over how long the plant stays in the vegetative growth period means you have all the time in the world to let her recover before switching to flower.
The same is just not true with autos. Heavy defoliation of any kind will certainly result in some form of growth stunting, and this will 100 percent decrease the final yield, and could even have negative effects on the quality of the final product. Stick to soft and easy methods with your autoflowering genetics for the most bulletproof results.
Another popular option in the autoflowering marijuana growing community is to refrain from actually removing the leaves from the plant, and instead try to tuck them out of the way. By tucking the two fan leaves that accompany budding sites underneath and carefully crossing them over, it is possible to effectively keep them folded nicely out of the way. This means that the flower receives full light, without needing to impart any real stress on the plant whatsoever.
Then there is the technique commonly referred to as ‘Pony tailing’. This technique has only really come to widespread prominence in the last 12 to 18 months, but it seems to really work. We have implemented pony tailing into our last three autoflower runs and have found the results really do speak for themselves. By using cable ties to carefully bunch up the newest growth (the crown), you allow extra light penetration and room to the branches just below. This method seems to boost branch production, without causing any heavy stress. Perfect for autos.
So, there we go. Everything you need to know about defoliation and autoflowering genetics. If you are looking to push those autoflowers just that little bit further, then defoliation is certainly an option – but do it with caution. Pony tailing and leaf tucking offer a great (and far less stressful) solution for autoflower growers who want to get the most out of their genetics.
We have found that light defoliation mixed with some leaf tucking and pony tailing works absolute wonders with both indoor and outdoor autoflowering crops and can increase the final yield by upwards of 20% when conducted perfectly.
Happy growing, and good luck.
Do you still have questions about autoflower defoliation? Drop us a line in the comment section below!