Is 4ft. sufficient for a 400W MH?

Here's the scenario, I have a closet that is 4x3ft and the height is about 8ft. So I splitted the closet into two compartments, giving each about 4ft of height. Each of the compartments will have a 400W metal halide. The bottom has 6 plants right now and the top I will plant to put 8 plants when I make the clones. My question is, is this sufficient height so that my light isn't too close to the plant that it will cause burning of the leaves? I have one exhaust vent but no intake vent, just a hole at the bottom which, hopefully, will passive air in. I dont think of putting another exhaust fan in unless heat becomes an issue. Any takers?

you will need a forced-air hood, or light tube ... MH is so damned hot, just an exhaust fan in that confined space aint gonna cut it ... in fact, if you haven't purchased the MH yet, I would pass it up, and go with CFLs, ... they are much gentler on your plants, and will grow outstanding plants with sufficient wattage ... :smokin:

Light tube? What is that. Yea, I already bought them metal halides. I was using flourescent before actually but these Halides are quite better cuz they're so damn bright and I can see my plants are loving it =D I only have 1 exhaust fan because I leave the closet door slightly open most of the time, except for when Im away.

Look Out for that heat.you will burn the plants to there death.I use a 400 watt Mh&HPS the Mh Vegetative stage and switch to HPS in the 12 hours light cycleof flowering.The light reflector has a 6' intake of fresh air which is pulled into the refector across the bulb and out exhausted to the attic with
6" vortex inline fan at 449 cfms.So the heat of the light is cooled down awholelot.I do have a aircondistion vent in there too.The closet is 2'Wx8'Lx8'H
The temp is around 73*To79* and the Humidity runs between 45% to58%
most of the time its about 49%.I build a dark room vents in the door.One near the top and one near the bottom.At the bottom I have a 3"x3" axle fan pulling in air from the room into the grow closet.The light is about 16 To 18
inches from the plants at all times. Do this and you shouldnt have any trouble
with heat.

Let Me know how it does.:dance: :dance:

Crazy,

Why don't you do what I do, double stack your closet. Since its 8 ft in height its probably easier for you to get away with the heat problem because of your good venting system?