ventilation in a cupboard

Ive got 6 clones from a plant I was growing outside I'm just about to start growing them in a cupboard about 3.5'x2'x4.5'.
I havent got a extractor fan or anything and was hoping maybe a small portable fan would be enough to circulate the air and keep the heat down in there,will this do? I havent grown in doors before so any thoughts on this would be appreciated and other problems i may incounter,thanks.
Also how far should I keep my light away from the plants its a 600w MH and does it change from veg to flowering stage

yeah it will circulate air. but without a heat vent, its an easybake oven. and with a 600w MH bulb that closet is gonna be hotter than fuck.

plus, u need to vent o2 out, and get freash co2 in. otherwise youll stunt the growth.

you need cross ventalation. ie fresh in old out. do u not have an attic or something?

Now theres an idea P hadnt thought of. I have an attic just above the ceiling of my grow closet. Would it be good to run an exhaust fan on the top of the closet to disapate the heat? You know like celing mounting the exhaust fan. My only concern would be that sucking out heat would also remove smell, this would eventuallu make it out of the attic to my neighbors. So is there a way to hook a carbon unit up to filter the air before it would be exhausted through the celing?

obviously.... and that 600 watt shouldn't be any closer than 1ft... but also don't put it any farther than 4ft from the lowest buds. The closer, the better.

nah i live in a flat on the middle floor so i mite have to accept my room is gona stink of weed, open the cupboard doors on a regular basis and keep my window open .Hopefully this will do the job.Its one of those coolshade lamps as well if that makes any difference.
thanks for the ideas tho