Amazon: that is because sun is moving over the sky. You could reach that also with light railing. That is not a case in tight spaces.
Here goes what i understand under fan leaves of cannabis (exactly fan leaves and exactly cannabis)
When new node grows - it has a fan leave or two (it happens even three) fan leaf. While node is developing - fan leaf are feeding it. After removing leaf that node stops to develop normally, but then (in veg) always will be another node after one!
So, let's go further. After node is developed and fan leaf is getting away from main stem on it's own stem - that leaf is no more a builder, it becomes a reservoir of food, food for predators (as was said before), also a protection from any kind of bad things that comes from feed. Yes, they do absorb light and yes, they do make bigger yields in open space, they partially feed bud sites also. But that is only partially, as buds are fed directly by sugar leaves. If removal of fingers / leaves is done just in time - that causes plant to defend itself and grow another green mass. In veg that is new leaf and nodes, and in flower that is more small fan leaf (more in size, not in qty) which are growing straight from the buds. These are important till last phase of ripening, they helps to develop bud sites with sugar leaf. And in the end these fan leaf are often eaten by plant it self and tossed away.
Resume: fan leaf are needed and if removed - that should be done with understanding and care. They are mainly for developing plant itself, till bud sites are fully in place. After that they are not so needed and can be removed, if that is needed. And that is needed when spaces are tight mainly. And main thing is - buds are mainly fed by sugar leaf, not fan leaf. That is mainly, so always need to remember, that if there is a method to bend and tie everything - better do that, do not cut. But if there isn't - do that. And always do that only if plant is healthy.
Here goes my plant with extreme defol. 0.12m2, CFLs. And im practicing more or less defol for more than 3 years now, can't imagine a grow in small space without that.
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