Quote Originally Posted by achilles
lets aim for sticky status!
2. cfls come in cool white (vegging, blue tint, 5,000k), and warm (flowering, red tint, 2,500)

4. Look at lumens, its suggested to have a minimum of 3,000 lumens per square foot of grow space. with a standard 100watt equivalent cfl bulb making 1,700 lumens, 2 per square foot is about right.
Referring to #2, thank you for this info. I've been searching for an answer like that for a while and i finally stumbled across this thread and I'm very happy that I did. Thanks to Achilles and Letseeya for the info from this thread.

Referring to #4, I have the same question that letseeya posted. It's strange that I hear about 100w CFL's that produce 2k lumens, then I read a grow log and someone says that they have a 30w CFL that produces 2.5k lumens (not factual, just an example). How is that possible?

Another question...how do lumens work excactly? I read somewhere that you don't just add them up. What matters most is the same type of lumens or something like that? I read this on a grow log, but the description was far too confusing for me to follow. A simplified answer for a noobie would be much appreciated!