you can start a lot of plants under those lights but if you were trying to bring them all the way to fruit, I would say you would only be able to do about 2-4 plants. You've got a total of roughly 240 watts at around 50-70 lumens a watt = 12,000 to 16,000 lumens. Which you want at least 3000 lumens a square foot. CFL's and T-8's also have poor canopy penetration.
These are just rough estimates (and really there's a lot better ways to figure out lighting) but somewhere for you to start in your planning process.
If you're just starting seeds and planting out in spring, you could fit about 30-40 plants depending on how well they grow, in a 4X4 area with that kind of light. It would be really tight but you could do it.
Just my 2c