CFLs have the neat ability to be easilly swappable. Here is the light spectrum schedule to date on my tubgirls, which started as 5 plants, culled to 2 females:

11.20 - 4 x 27W 6500K CFL (108W) (sprout)
11.27 - closet coversion: 4 x 27W 6500K, 3 x 27W 2700K (189W) (spring)
11.30 - swapped 2 x 27W 2700K w/ 2 x 27W 6500K (summer)
12.02 - swapped 2 x 27W 6500K w/ 2 x 42W 2700K (219W) (midsummer)
12.08 - swapped 2 x 27W 6500K w/ 2 x 42W 2700K (249W) (late summer)
12.13 - pre-bud. switched from 24/7 to 18/6
12.17 - swapped 2x 27W 6500K w/ 2 x 27W 2700K (autumn)
12.20 - bud. switched from 18/6 to 12/12
01.03 - added 1 x 27W 6500K sidelight (276W) (stretch maint.)
01.05 - added 1 x 27W 6500K sidelight (303W) (stretch maint.)

This should give you an idea of what you need to get a group of plants through their life in a small closet.