^^ CFL stands for "Compact Fluorescent." It's a fluorescent bulb scrunched down into the size of an ordinary incandescent lightbulb, rather than being a big long tube. They look like normal lightbulbs, but a coil instead of a normal shaped bulb, you've probably seen one somewhere. CFL's are marvelous for indoor grows since they're so nice and small, relatively efficient in terms of energy, heat and output, and are very reasonably priced.
To the original poster, I'd definitely plan on using CFL's. HPS has a lot of perks, but for the smaller, more casual, or space-restricted grower, CFL's are unquestionably the way to go.
In veg stage plants like blues, and in flower they use more reds. That's how the sun works in various seasons; in summer, the sun's rays hit earth closer to the perpendicular, so the light is less filtered and we get a lot of intense blue rays. Then in the fall, as the alignment of the earth/sun changes and such, the angle of light rays hitting earth are a lot more acute, which filters the sunlight through the atmosphere more, stripping away lots of the intense blues, leaving a higher range of reds, which plants learned to make use of for flowering.
So, I use primarily 6500K lights for growth stage. My veg setup for my current grow was three 42W 6500K bulbs and one 2700K bulb on one plant. For flower, I just reversed it, giving her three 2700's and one 6500K. I'd recommend you use a similar setup, it's very practical and I can tell you, gets gorgeous results.
