Read this sticky http://boards.cannabis.com/indoor-li...uch-light.html for your needs.

2000 lumens sq. ft./21500 lumens sq. m. = Absolute minimum for growth. You won't get much from this, especially after the plant has grown a bit. Not really enough to flower well.

3000 lumens sq. ft./32250 lumens sq. m. = Pretty Good growth. Enough light for the entire light cycle, although your yields may be lower.
4000 lumens sq. ft./43000 lumens sq. m. = Very good growth. Once you pass around 3500, growth rate and ability goes up fast.

Over 5000 lumens sq. ft./53750 lumens sq. m. = Optimal growth. Dense growth in all stages.
After I done lots of reading on CFL lighting, I ended up with PL-L. That's the most effective CFL I've ever seen. You can consider T5 ligthing as well. You have good space to use long tubes.

Check out CFL and Tube grows and compare it yourself.