When to start sexing

I'm growing some big bud under fl light and right know there on 24hr. My plants are about 10 inches about 9 inches wide and starting to smell like mj. I'm wandering when do I start to taper off the lights and try and get the plants to sex. And should I do any pruning of the plant.

Thanks in advance:rasta:

Hey. Yea man, totally prune it!! Don't prune in flowering, only in veg so hurry and do it now buddy!
I'd wait till after you prune it and your plants are about 12" tall, then go for the 12/12 and watch those nuggies grow ;)

Well... If you want your plant to stop growing for a week or more than yeah, prune. But why? The leaves are being used to make energy. If you start cutting them off the plant will stop growing and concentrate on the damage you would have done... so why bother?

If the plant doesnt need certain leaves it'll make them die off naturally which doesnt stunt growth.