Using Bushmaster during veg??

so i started my outdoor grow in feb. Everything reverted back nicely no problems at all, except a few are getting too big and it's not even july yet. I picked up some 'Humboldt County's Own Bush Master' my qeustion is , can i use this during veg to slow the plant from growing taller or will it not work? if not can anyone suggest anything to keep the height down, their already 6 feet tall and will get taller before flower then even taller during flower. i cant let them get taller than my roof.

You should have topped that plant a long time ago dude... What were you thinking when the plant was 4 feet tall?

yo ive been watchn your grow on youtube! good stuff! I personally dont use bushmaster but I have friends who do and it doesnt really slow the upward growth, what it does is cause the plant to branch out. if your looking to keep your girls lower than your fence you can top, fim, and lst... keep up the good work i like your vids on the tube! take a look at my thread when you get a chance, you might like what you see!