Well, most people swear by HID lighting (High pressure Sodium mainly) for flowering which will get you pretty incomparable results compared to CFLs, but I remember seeing someone that grew some pretty nice buds with CFLs. You might want to pick up a couple more bulbs when you do flower, and make sure they are warm bulbs or more towards the red spectrum for flowering. But yeah, you can definitely use them, you just won't get the yield you could have with HID.