I've been planning a grow for some time now, at first I flirted with the idea of doing a cfl grow because I want to grow in a closet, but then I decided in the long run a 400w hps will make me happier, but my questions are: how many plants can I put under the 400w ?...I'm going to grow some of mandalas speed queen, I know I need a ballast, but do I need anything else...or does the bulb screw into the ballast and the ballast plug into an outlet ?