That's enough light for CFL. You can get by with 300 in veg. You might add 50w in flower. But, 46w/sq ft isn't bad for CFL. 50-60 is probably better in flower. But, it will work.
You'll have to transplant to 1gal containers and go 12/12 early. You can't get too large in that space. (Autoflowers work well in a 4' tall space.). If you're growing photosensitives, they'll stretch a lot when you do 12/12. You'll want to familiarize yourself with topping, low-stress training (LST). It depends on the strain. Indicas won't stretch as much as a sativa.