Plenty of ceiling height is very important. 6-8ft allows the heat to rise and if using HID light?...allows you to raise the light as the plants grow upwards....otherwise; you have to trim, FIM or scrog....to maintain enough distance from the canopy.

EDIT: well if just vegging for transfer to outdoors...height is less important

you should be able to harvest in the fall of 2010...:stoned: