Trimming Cannabis Plants
It's rare you would want to disturb a cannabis plants growing habits. Generally there are only three times you might cut or trim a cannabis plant. To encourage more branching, to remove large fan leaves and to encourage even light distribution or remove lopsided or unwanted growth.
Encouraging More Branches
The first is when you want to split the main stem while the plant is in vegetation growth stage to encourage more lateral branches and nodes on the plant. Depending upon the species and growth habits, where you are growing and the limitations of height you have (growing indoors), different techniques will yield differing results.
Generally trimming the plant while it's young and splitting those stems by cutting just the tips of the newly forming leaves on a young cannabis seedling will force it to grow two stems. This can be repeated to get the desired phenotype or shape required for the conditions. More tips will spread light evenly across the plant and increase yields growing indoors and allowing for the optimum height away from fixed light structures.
Trimming Plants With a Purpose
Another time to trim plants is during growth to encourage the rest of the plant along with increased light. Evenly distributing lumens indoors reveals the best yields.
Diseased, lopsided or pest effected growth should be removed. By removing anything strange you limit the chances of diseases spreading, also keep an eye out as this may be a sign that something else is happening in your grow.
The only time you would never trim is if it's a giant main cola reaching to the stars.
Trimming Fan Leaves
Trimming the plant of fan leaves (which steal nutrients) is important, but there is a trick to trimming which few know, which will thicken the stems which the flowers are forming from. When trimming a fan leaf, leave approximately 2cm on the stem back on the plant. With this remaning 2cm of stem, squeeze/crush that remaining stem from the cut point back into the trunk. This will cause the trunk stem to grow thicker and thus improve the rate at which the flower can absorb nutrients.
Best Practices For Cutting Cannabis
Use very sharp sterilised cutting instruments and make clean fast cuts. Try to not cut too close to the main stem and avoid tearing the plants 'bark', plan your cuts well and make them precise. If you make a mistake, then you can bound the plant to heal wounds and keep an eye on anything you disturb.
This is a section from our harvest phase of the grow guide. Please also see our glossary of cannabis terms used in Australia.