If it were my closet... I'd be looking at 2 options: 1 - 600w digital system with a switchable ballast. You can dial down the power when needed... seedlings, veg, too hot, etc.. 2 - If the closet is wide enough, a 4' T-5 panel with 8 tubes, which would be equivalent to about a 400w system. You also need to be thinking about ventilation and temperature control.. Lights produce a lot of heat. If you solve these problems up front, you'll save yourself time/energy/$$ in the long run and have a more successful first grow. Good luck! Farmer Rich