How many can I grow?

I can plant up to 45 plants. I have an 8x8ft room, which is 64 sq. ft. Usable planting space is about 50 square feet. I am using a 1000w light. If I plant all 45, how long should I veg them for before flowering to make sure they don't get too wide? They're indica dominant master kush.

Hrm, 45 plants under only a single 1000w HPS is pushing it. If i was you your best bet would be to 12/12 them right off the bat. It tends to create a single "Popsicle" type plant and bud you generally end up with a much smaller plant and less yield than if you veg. but if you got 45 crammed in together and get at least a ounce per plant (which I have done using 12/12 from seed) you should be fine lol.