YOu really want to consider using CFL for your Cloning/Veg section.

HOwever, you are going to have to address the fresh air in and fresh air out rules. Yes you need a fan, but you will need to rig the setup so there is a way for the hot air to be removed from your space.

Damaged walls can be repaired
HARDDON Reviewed by HARDDON on . closet ventilation problem!! I'm tryin to put together my first grow room. ive got decent closet space. its 5ft x 8ft x 2ft deep with sliding doors. But I need a lil help w/ an acceptable way to ventilate it. I can't damage walls, so couldn't run any kinda duct work. could fans be used to cirulate air, or must there be a way to some way for air to get in and out of the closet. Also, I wanna partition the closet in a flowering room and a cloning/veg. room. Thinkin about 400w HPS for the flowering section and 150w HPS Rating: 5