What I was going to do, is not put a lid on it, and just hang the light down into the box and raise it as the plants grow via pulley.
Dude
thats going to get very hot in there. thats 100W per square foot. you will need a very good ventalation system to get the temps down. i would sell the light as new and buy a 250W HPS for it. and about the plan to have no roof. what are yoy going to do when you flower light will get in during the dark period.
WiZaRD
The area i'm growing in is 100% dark, so the only light is from the HPS light, so when I do the 12/12 it'll work fine... I figured it'd be to hot.
Webmaster
It will get hot but I woulnd't lower the wattage. Just make sure you have a vented reflector hood and hook a fan up to it. Then also make sure you have a vent fan in the box that keeps the air being replaced every few seconds. You should be fine, the extra wattage will make much better buds. You might not be able to get away with this box in the summer depending on where you live.