During the first few weeks of flowering, is it safe for the plants to be topped or would it cause more harm than good? And if they shooldn't be, then how would you suggest controlling overlapping growth?

I would just bend what is in the way out of the way. Don't cut it, ya' lose the cola. Only cut it if you have no other choice.

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what if your plants are 6 feet tall

Well, if your plants are 6 foot tall...........Bravo to you my friend!!
I'd like to see pics of that shit!! You can still bend it over, just grab the topand pull it slowly to one side,back to the other side, and back the other way*****SLOWLY, AND CAREFULLY!!!*******!!!

A plant that size probably won't bend much due to the more wood like stalk and branches. If it's flowering, then be even more careful, cuz it's strangthening those branches to carry heavy buds on that 6 foot plant, with probably 4 or 5 foot branches.

But you can still bend the very top of the plant, at least to a point lower than the next set of branches down to give you a little more room.

Dude, i really want to see this 6 foot plant!!! +rep to ya' for a pic!!!

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