Sounds good but you don't need 4x4's. 2x4's are more than adequate. If it's outside, you need to take some precautions to keep the floor from rotting, which can happen real quick in certain climates. You might want to consider insulating.

You might get a few ideas here. DIY - A Growroom Log.

Good luck!

PC :thumbsup:
PharmaCan Reviewed by PharmaCan on . making a grow cab here is the plan 8ft tall, 4ft wide, 8ft deep Constructed out of 8x4 plywood sheets, and 4x4's. Venting, A/C unit ( window mount), and 2 fans, inside to provide turblence. Dual 600 watt hps for lighting with reflectors. Rating: 5