For years the words defoliate and autoflower have been avoided in the same sentence by most growers, with the idea that autos should be left alone, aside from low-stress training. The reality is that defoliating autoflowering cannabis has its place in your grow, but requires the right methods be used to avoid a lower yield. It is still a topic of debate among growers, but there has been a larger uptake in recent years as auto genetics have improved, of growers using defoliation to increase their autoflower crops.
Unlike photoperiods, which can be defoliated fairly regularly throughout its life cycle without much of an issue (if you slow the plant down it’s okay, you can just give it some more recovery time before switching to flower), a stunted autoflower who is spending too much time healing and not enough time growing, is going to result in a lower yield.
Only For The Fit
Firstly, and most importantly… Defoliating your autos should be reserved for healthy plants that are thriving, if your plant is not doing great, don’t make things worse for it by adding stress. Growers who have plants already showing signs of stress should certainly not be defoliating.
Not all genetics are equal either, you should learn to be able to tell whether a plant is going to benefit from a defoliation or suffer from it. Some genetics do not grow as well as others and may suffer more than benefit from defoliating. Leaf tucking should remain your primary method of clearing bud sites, but for more light penetration and to increase airflow around buds, you can look at defoliation.
Timing is Everything
When defoliating an auto, you first need to ensure that it has established its growth and is not in the early stages of life. A good idea is to wait until pre-flower at a minimum before considering any kinds of leaf removal from your autoflower. Taking off leaves during the vegetative stages, especially early veg, will result in a slowing down of the plant growth and result in lower yields directly from the lack of vigor the plant was able to grow with during that stage.
It is widely accepted that if you do wish to defoliate, it should take place from around the beginning of flower. How long you continue to defoliate for is up to.
Taking it Slow
There are two approaches for those that choose to defoliate autos, you can do it all in one go, providing more stress to the plant in that immediate time, but then having her focus strictly on growth after that point, or the seemingly safer approach of removing a couple of fan leaves every few days. Removing fewer leaves means that there is less of an immediate stress on the plant and she’s able to still focus on the bud development throughout, with only some of her energy going towards the minor healing of the fan leaf removal sites.
As for which method is best, there are those who argue for both sides. However, I am personally a fan of the slower method, I will remove fan leaves as they block the bud sites. So far I have not had issues with visible stress or diminished yields using this methodology.
How To Defoliate Autos
There are those who feel like heavy defoliation does well for them on their autos, while others recommend a less heavy handed approach. I personally prefer basic defoliation of fan leaves that block bud sites, or excessive fan leaves that obstruct airflow through the buds. I find myself typically removing about 20 fan leaves in the first 3 weeks of flower, stopping around the same time that the stretching phase stops.
Remember that your bud sites still use the fan leaves to convert light, and you should make sure not to remove too many as this will negatively impact your bud growth.
Some prefer to remove even the lower branches if they look too weak to produce good bud sites, though this fairly heavy handed approach is one that should be reserved for experienced auto growers.