That's the rule of thumb for the bare minimum with CFLs, not the recommended or ideal. Take Bigdad for example, who posted on this thread -- the rule of thumb says that 150w of CFLs is the threshold for 2 plants, but he is growing 2 plants with more than double that.
Thanks for the replies. This is not my first grow (did outdoors this summer and got me hooked). I really just need to scope out where I am going to grow in order to make mg decision. If I have room for a HPS and ventilation to match it I will go for that but I'm planning on a limited space so cfls seemed like a decent alternative.
You have room, trust me. HPS doesn't take as much space as you think, and the ballast can be wall-mounted. My tent (2' by 3'), which is small, with a 250w, which can handle a liiiiiitle more space than that, makes my closet warm in a house that is normally at 65-70 in winter. It's not so bad. If you live in Miami for example, higher ceilings are actually an appropriate idea to help (not a 100% fix, just help)
Very true Toasty and I do agree that hps is the way to go for flower, but I'm just working on getting him to a starting point with cfls.. I do realize that it is the bare minimum, but it still works as a good rule of thumb for those with little experience.. A good set of cfls for me can create a decent vegg room at a minimal cost.. Guessing from the way the user is posting and with the holidays coming up they maybe be low on money and if not being a new grower they may be a little apprehensive about buying a hps until they make sure they have the room/desire to grow indoors.. The good thing about starting cfl's is that they do fine in vegg and personally they gave me the opportunity to explore growing without investing too much too quick.. It also gave me the setup for a perpetual grow with an hps flower room in no time at all.. If he wanted to flower with cfl I'd suggest double to tripling wattage, but once he sees his beautiful girls it may be hard to keep his hands off of an hps.. I'm just here to give a hand since I as well began with cfls and still utilize them as my vegg room..