Have you thought about ventilation? A good exchange of air in the room is something that you will want.. 400w doesn't sound like much for 5 plants, I have 2- 600 watt going on 3. 2- 400 would be probably be good.. If you cant get another light a good cab, scrog grow would be good... also I would research lst in the faq or thread search tool. Although you may end up with a room that is large enough to allow you to just let them grow, I think you would probably do better with a more compacted grow.. If you can up the wattage the you can get yourself a lot more yield with better trich formation..
follow the link in my sig, check the journal there is a ton of good info in there from people who really know there shit... also follow their links and check as many journals as you can.. Ive really found that the best way for me to learn. With the journals you can see how things actually worked out when trying new things that might work for you...
sry such a long post, Im high as hell and have a bit of babble in me now!!
Peace and Good luck!!!
HHM~~~TLB
