lighting problems - help!

[neonweed]

my grow box is 45 inchs long, 32 inchs tall , 20 inchs wide, and i was going to get a 400 MH but everyone told me its to hott for my little box, i was thinking about either going with a 250 watt MH or HPS or going with this led thing but the problem with the led liht in the description is that its 4f long and my box is only 45 inchs long, which is 3 inch's off


this is my grow box

i hope someone directs me to the right kinda of light source i need for my box.. i will be putting that white shit in the inside < i dont know what its called.... and a fan on the side of the box < how big should the fan be with the light yall direct me to??? and a chest top on it with door hindges. i will also be putting a hole on the other side for a an air escape hole

 

[Graytail]

Your main issue is clearance between the light and the plant tops - heat, not so much. Sure, you have to vent the heat, but you just can't put plants that close to HIDs - you need 6 inches, even for the 250s - the tops won't like it.

So that leaves you with flouros or LEDs. A bunch of small CFLs would work great in that space. LEDs also need more clearance than you'd think. 3 watt diodes need a foot or more. Maybe a couple cheapo LED panels with 1 watt diodes would be best?

A couple 3-4 inch vents and a computer fan should vent enough air for that size volume.

 

[lushgreen]

Graytail is right. Even a 250 HID needs room or you'll get light burn. CFLs would be the best option for a small box like that as they can be kept really close to the tops and don't pump out much heat.
I'm not experienced with LED growing so I can't comment on them. Depending on the total wattage you could have light burn issues if too close.