Pruning is essential for improving the quality and yield of your cannabis plants. It’s an intimate practice between the gardener and the plant and allows you to closely look at your plants and check up on their health.
It might feel strange to intentionally cut off bits of your plant, but these parts won’t produce quality buds because they won’t receive a proper amount of light—they’ll get shaded out by the buds and foliage growing above.
Cutting off the branches will allow the plant to redirect its energy and resources to the quality buds that will receive plenty of light. You also want to prune off yellow or dead leaves on the plant—they have no use and will only waste the plant’s resources.
Pruning also creates open space in the middle of the plant, allowing air to flow through it more freely and letting light penetrate deeper, keeping the plant vibrant and healthy.
What to look for when pruning
Quality buds grow where the plant receives a lot of sunlight and airflow, particularly on the top of the plant. You’ll want to remove:
Low-down branches that receive little sunlight
Leaves that are dying off because of lack of light
Bud sites that are low down and don’t receive a lot of light
In the early stages of growth, a plant is narrow enough that most of the foliage will receive plenty of sunlight. Start pruning your plants once they begin to take a bushy shape, and top them to promote this bushy growth.
As a plant grows and bushes out, it’ll start to take a shape and define the canopy. This will give you a sense of where the quality buds will grow so that you can start pruning away the unnecessary portions of the plant.
From this point until about 3-4 weeks into the flowering stage, you can actively prune your plants. Once well into the flowering phase, you want to cease pruning—it can cause the plant to start producing vegetative growth again, which will diminish the size and quality of your yield.
How to prune your cannabis plants
Grab a pair of pruning shears, usually some Chikamasas or Fiskars, for quick work on small branches and leaves. Keep an additional pair with more strength nearby to cut larger branches.
Keep your clippers/scissors sharp and make clean snips—this will keep the plant healthy and prevent infection and damage.
Remove large branches first. This will allow you to clear out as much space as possible before you begin the more detailed work. Start with branches on the bottom of the plant. These won’t receive enough sunlight and will never become fully developed buds.
Cut off branches that are growing up into the middle of the plant, underneath the canopy. These branches will get shaded out and also won’t develop full buds.
Prune any small or dying branches or leaves.
In the days following a pruning, your plants should go through a burst of growth—the open space will allow extra light to get to the plant.
Source: https://www.leafly.com/news/growing/how-to-guide-for-pruning-marijuana-plants