need some advice... first grow

finally got my own place and i got a pack of cali orange bud seeds from nirvana, got a closet to work with and i ordered the 400 hps from insidesun, should be here within a week.. just started 2 seeds in jiffy pellets and my space is give-or-take 3X3.. question is will i be able to use my 400w hps through the seedling and veg stage if i keep my light far enoough away?? im on a real tight budget right now and was barely able to get the hps so i really dont have any money for any other lights. any advice would help

what kind of ventilation will you have?

what height range are you working with? what type of enclosure?

I've had a few successful grows now and I haven't used anything else but my 250w hps in a small cabinet. I think the sodium light is awesome for early veg. I've noticed that my mature plants look a bit smaller than they could if I vegged under whiter light. anyway, don't even worry; they will grow sublimely under an hps alone even from the seedling phase. if budget is an issue just go with what you have and any upgrades in the future will yield somewhat better buds.
just make sure your plants get fresh outside air and keep temps under 85 F

height range is gonna be about 5-6 ft. as for enclosure im going to set up some walls with mylar, still thinking of different ideas for the exhaust.. any ideas would be helpful, thanks

Sounds like you should be in business as long as you can get proper ventilation a.k.a. a fan to blow out the hot air and a way to get fresh air into the room. (Even opening up a window in the room would do!) Just keep your plants at least 12" away from the hps. I would recommend supplementing your HPS with some CFL's. They are relatively cheap. You can go buy one of those work lights, remove the aluminum reflector buy one of those sockets that allow for 2 bulbs in one and watch your girls just love it! Happy growing and Peace!