I would look at putting a fan in the back of that box. It will save you in the end. Even computer style fans. The lights can get pretty hot I have found in my small cab.

YOu arer gonna want a fan at all time around your plants moving air. This will cycle carbon dioxide around to the plants leaves making them grow.

Thats all i really know 100% forsure about growing - that cool clean air movement is a must for decent nugs

kd_special