What it is
Removing big leaves (the "fan leaves") from the lower and middle part of the plant. It is one of the most debated techniques: done right it helps, done wrong it stresses the plant.
What it's for
The big leaves at the bottom get almost no light and trap moisture between the branches. When you remove them, air gets in (less fungus, especially botrytis) and more light reaches the buds that were covered. The small lower branches that will never make good buds are also often removed ("lollipop").
When
At the end of veg and when flowering starts (many repeat it once at 3 weeks of flower). Never remove many leaves at once: leaves are the plant's solar panels and its food reserve.
How to do it
You remove the big leaves that cover buds or that are inside the plant without light, and the ones at the bottom. Cut the little stem (petiole) close to the branch, without tearing it. At most, 20 to 30 % of the leaves at a time.
On autoflowers
Carefully or not at all: they have little time and few leaves, and every leaf you remove costs them yield.
Before you start
Every prune or training is a wound: the plant spends energy closing it and adjusting. That is why it is only done with a healthy plant that is growing strong. If it is thirsty, has pests, mold, a deficiency or was just cured, let it recover for a few days first: one more blow to a weak plant can kill it.
▲ Pros
- More air and light below: half the chance of botrytis
- The top buds fatten up more
- Can be added to topping, FIM or LST
🎮 Practice it in UnderGrow
It's done from prune, once per plant, and can be added on top of topping, FIM or LST. At the end of veg or in pre-flower it adds roughly 8 % yield (less on autoflowers); in full flowering, half and with more stress. Slows growth for about 3 days (4,5 in flowering; 5 on autoflowers). It always halves the botrytis chance. First, check its health and stress: the technique adds its stress all at once and it can kill a plant with low health. Health only goes back up with the stress bar below 20 %.
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