Actually, 50cfm is practically nothing, but for your space it might work... It's always good to have too much than too little ventilation.

360w of cfl in a 6cf area is probably going to get pretty hot. Test your setup before you start planting anything so that if you need more ventilation, you can add it. Temperatures should be 70-85 degrees F. Too far below 70 or above 85 will stress the plants and reduce your output.
dgsgandalf Reviewed by dgsgandalf on . Amount of light vs. heat generated Growing in 2ft x 1ft footprint, 3ft vertical space (6sq ft). Want to run 12 30watt CFLs. Temps between 72 and 78F currently running 6 23watt CFLs. I know CFLs do not create much heat, but that many is bound to create some. Anyone have any guesses as to how much? Options are 50 or 70CFM fans. Think 50CFM would be enough to suck out a lot of the heat? Rating: 5