When Can I Start to Flower?

My plants sprouted on September 26th. I grew them with CFL's up until October 8th, I then switched over to a 400 Watt Metal Halide Light. I was just wondering what is roughly the time span they will take to be able to support buds. I am growing in a closet grow room and I am trying to grow my plants short and bushy. Any input is much appreciated.

When the plant is mature enough.

You gotta decide for yourself we can't do that for you trial and error buddy.

Depends on strain and how tall you want to grow it. 18 inches tall is the general rule for growing indoors with a hybrid,with a pure indica plant 12-36 inches which will finish with a plant 2-6 feet or with a pure sativa 12-40 inches to finish with a plant 3-21 ft tall since sativas will most likely triple their height instead of double like indicas.So strain and space dependence plays a key role in flowering,so stop at a certain height and multiply by 2-3 and expect that to be the finished height,with a 400w don't expect to grow anything over 4ft and get great buds unless you lollipop or training in general (top,lst,supercrop,fim,scrog...)

Thanks guys. Ill guess I'll play around with it a little and see what works best.