As a grower when you defoliate cannabis plants you are removing the leaves and some branches to keep the air flow around your plants moving, this will also allow more lighting to get down to the lower buds in flowering.
Why Should Growers Defoliate Cannabis?



The main reason to defoliate cannabis is to remove leaves that would otherwise block light from getting to the plant’s flowers. If it is completed correctly it can also help plants yield a larger harvest.
If the grower does not have a moving grow light in the grow room there will be permanent shadows in your grow room over the plants. Removing lower branches and leaves also will help improve the airflow under the plants, helping them battle pests and have been dry/wet cycles while growing.
Another great reason to defoliate is that your plant breathes through its leaves, when the plant has leaves laying over other leaves it can release humidity and will get water between these leaves. This moisture between the leaves can build up and provides a great place for fungus and molds to develop.



Defoliate Cannabis in Vegetative Growing Phase Indoors



When removing branches, leaves in the vegetative state growers will mostly want to stick to lower branches and leaves. Look for any branches that will not get enough light on the bottom of the plants, these branches will not get enough light to grow any amount of good quality buds.
Also during the vegetative growth phase it is a really good idea to remove any lower leaves that will not get enough lighting. Removing these leaves now will keep them from dying in the flowering phase of growth.
When that happens they will die and rot on the top of your plant pots, attracting bugs. They will also get mold on the dead leaves that can spread mold spores to your growing buds.
Defoliate Cannabis in Vegetative Growing Phase Outdoors



When your plants are growing outdoors there really is no need to defoliate the plants during the vegetative growth stage. All the leaves will be getting lots of light from the sun. The leaves all over the plant will be used by the plant to generate energy, grow stronger and grow much faster than without those leaves and branches.



Why Removing Yellow Leaves is not Cannabis Defoliation



You will see many articles all over the internet claiming you should remove yellow leaves from your plant. This is never a good idea. When your cannabis plant leaves are turning yellow this is a sure sign that your plants are lacking in nitrogen. The plant is removing the nitrogen from the leaves of the plant and using them to help new growth form.
If your plant is already lacking nitrogen this issue needs to be fixed before you start removing yellowing cannabis plant leaves. By removing those leaves you are only going to make the deficiency worse.
This is especially true if you are growing completely organically, as the plants will need all the nutrients they can acquire for growth, as the organic nutrients break down slowly to feed the plants unlike liquid nutrients.
Is Cannabis Defoliation Low Stress Training?



Growers should be aware that LST is different from defoliation of cannabis. LST is using low stress growing techniques to grow cannabis, when using this method of growing the plant is never damaged just moves to keep the plant growing strong.
Using defoliation involves physically removing pieces of the plant to remove shade and gain better air flow and access to grow lighting.
The Debate over Cannabis Defoliation Techniques



As many growers that you will find that say that defoliation is needed you will find as many growers equally that will say it is not needed. There is much debate with growers about whether this method works or is even needed. Personally we have used both methods for growing, and we have seen good results overall using this technique at the current times in growth and using the methods in this article.
When is the best time for Cannabis Defoliation?



When you have found that defoliation of your female cannabis plants work best when you do it in the first week of flowering. Your plants are already in a state of stress with the growth light change to 12/12 and removing leaves and branches will not really stress your plants anymore.
We have also removed leaves during the second week of flowering also with very good results overall.



Defoliate Cannabis in Flowering Growing Phase Indoors



Grower will start by removing all the larger fan leaves from the top of the plant. Keep in mind even when you remove all the fan leaves the plant will continue to produce leaves after the first week of flowering. Look for spots in your grow where these larger leaves are shading the tops of other branches. These are the leaves that should be removed first.
The tips of the branches are where the plant will get the most lighting, and where they will grow the largest flowers in the coming weeks of flowering growth.It is very important that they receive that maximum possible. Removing these large shade leaves will help with this.
Next look for any other leaves that may be shading upper growth branches. Growers should also remove these leaves as well. Your goal in the first week of flowering is to remove all the leaves that are shading lower buds, and branches that will receive enough light to grow larger buds.
Defoliate Cannabis in Flowering Growing Phase Outdoors



Since it will be harder to know when your plants have started the flower phase outdoors, you will have to take a best estimate as to when to start to Defoliate Cannabis Outdoors. Normally you will start to see more little white hairs protruding from the node sites of your plants. You will also start to see more of these at the top of your plants.
This is the perfect time to start to defoliate your outdoor flowering cannabis plants. Remove all the very large fan leaves you can do this all the way down the branches of the plant. These will typically be much larger leaves than indoors. Because outdoors your plants lighting from the sun is not stationary we don’t recommend removing any more leaves then this. The sun will move though the early fall sky providing a moving light source for your plants.
Can Growers Go Too Far When They Defoliate Cannabis?



When defoliating cannabis growers should remember that these leaves are holding valuable nutrients, water, sugars and generating energy for your plants. If you remove too many leaves and branches from the plant, it can shock the plant. This will remove the plant’s energy stores, making the plant grow slower.
Never trim too much as you’re growing your cannabis plant. Do your best to balance your growing plants’ new leaves and growth with defoliation of the plant..
Things you can do with Defoliated Cannabis Leaves



Remember you don’t have to throw all these leaves out in the trash after removing them. There are lots of uses for these cannabis trimmings. You can read more here about what to do with Cannabis Trimmings. We like to use them as a mulch around the bottoms of the plants.
Never Defoliate Cannabis after the third week of Flowering



Once your plant has reached the third week of flowering it will stop stretching towards the light, and it will also stop growing as many new leaves and focus its energy on flower production. It is never a good idea to remove leaves at this point.
Growers will also want to be careful not to remove and upper growing sites as these will grow the majority of your buds.
Can I Defoliate Cannabis Using Other Grow Methods?



Yes, using all these tips you can remove leaves no different than if you are not using a method like SOG, SCROG and LST. We find that defoliation works just as well for Low Stress Training once your plants start to flower. It also works very well to keep the lower plants clean of leaves and breaches.
Conclusion



Remember, these techniques are not hard set, some growers will do it differently. These are not rules to live by but more of guidelines to help you with defoliating cannabis plants. We recommend that you do what has worked for you in the past and if something is no longer working for you then maybe give some of these methods a try!