CFL light bulb watts? for PC grow box.

I am growing a lowryder #2 feminized plant in a PC grow box. There is one problem that I need your opinion on. I have fans and a power strip, but for one plant much CFL light bulbs will I need and watts.

Hope you can help.

If you can control the heat, a couple of 26 watt equivalents will possibly yield you a few grams from 12 weeks of work.