How many plants can I grow with 300w CFL?

I have a large closet space with a footprint of around 2.5 square feet and a height of around 3 feet. The walls are painted bright white for reflectivity. I have a single dual spectrum 300W CFL under a reflector that can be raised and lowered as necessary.

My question is, how many autoflowering plants could I grow under this light? I know more lights would help etc etc but this is the compromise that my better half and I have agreed upon for the time being.

I'm only growing for personal use but would love to have a few different strains to try.

@ 86w per plant... do the math
3 would be ideal, four pushing your luck.
make sure you position the lamps as close and as evenly as you can get them.
and one other thing- 300w of cfl's are nice, but a single 400w MH will really sell your better half on the subject, once she sees the difference.
good shit can be grown using cfl's but its an art form....

No way she'd go for a MH due to the heat problems. Already worried about the warmth that the big CFL puts out!
3 plants sounds fantastic, just what I was hoping for!

One more question, my current plant is around 18" tall so would I need to wait for it to finish in another 4 weeks or so before adding new plants? The reason I ask is that the babies will be around 20" from the light until they catch up with their big sister or until she gets the chop!

Yeah, you don't wanna grow the babies if they are gonna be like 8 inches from the light or whatever. One thing you could do is hang a light by the side of your big one for side growth and then just put your babies under that one, or you know what I mean. I agree with 3 plants thought if you don't plan on getting more lights.