when do i begin flowering?

i have a dumb question, i am curently growing 2 chonic plants (seeds from dr. chronic) they have been vegging about 1 month now and they are about 6 to 10 inches tall, when do i start the flowering period? they have been recieving 20 hr of light a day, 5 cfl lights at night and pure so cal sunlight during the day. they have been growing pretty fast. i can post pics if u need to see em first. thankx

You can flower at ten inches probably. Make sure you know the sex first.