Here are some old pics showing some "before and after" pics from pruning cannabis plants.
The first two pictures are different plants, and thus, not really a "before and after". The second two pics are true "before and after" pictures.
Pruning this way solves five issues in one snip.
1. Pests (most of which hatch in the soil, then climb, looking for food) starve on their way up the stalk.
2. The money you spent on nutrients goes toward the larger buds on the outside of the plant instead of vegetative growth, and small buds that are on the interior.
3. Any spraying performed will be highly efficient, and thorough.
4. Lack of moisture-collecting leaves and buds, allows for more airflow through the plant canopy; preventing mold/mildew
5. Harvest is cheaper/quicker. A plant with only "A" buds is quick to harvest, and dries quicker, than a plant with a lot of organic mass, "popcorn buds", and excessive stems.
#cannabis