Tin foil, Mylar, or simple flat white paint are all common. The paint is the best for manageability... no wrinkles, tears, maintenance etc.

Thanks for the ideas... guys, sounds like I'll probably end up going with white paint. I currently have large cardboard sheets hanging down wrapped in tinfoil, but that stuf is such a pia the keep from wrinkling, tearing etc... I was hoping there was some sort of high gloss chrome paint or something, but haven't seen anything with decent reviews. I don't know much about mylar but I think it would probably be a bit expensive to obtain, and really how much better than white paint would it be?

I do already have a fan on the table, so I'm good on that front. I'm getting a 4' 6 tube T5 light tomorrow. Just looking for a way to close off my grow to trap in some light, clean up the room, and lock in a bit of heat.

4' x 6 tube should provide enough light without having to trap more provided you keep the tubes close to the tops of the growing plants. Unless the whole area is especially cool, 6 tubes is going to provide quite a bit of heat and the humidity inside such an enclosure may end up too high, essentially a terrarium. Sounds to me like a real potential for mold and mildew.

That's a good point olddutch.. Definitely something more for me to think about... It's a weird situation.. If it's cold but sunny out my basement drops in temp because my tstat is upstairs near the picture window.... I could get a little heater for the grow room I guess. Electricity is pricy where I live , so I'd rather not. .,

I'll figure something out.. Thanks for the suggestions.

Better to have a thermostat inside the box that controls exhausted fans, and intake vents at the bottom. Here are pics of my grow box:

http://www.general-cathexis.com/images/LED2.jpg

http://www.general-cathexis.com/images/LED3.jpg

Observe the thermostat on the right side and two exhaust fans, one at each end. The front will be covered with an aluminized mylar sheet and the box placed on top of a bench with large openings that serve as air intake vents.

A nice feature of an aluminized mylar front cover is that, when the outside is dark and the inside light, you can see the plants inside without removing the cover.

I'm going to favorite this idea for a future upgrade. That's pretty wild.