watt to leaf size connection.

To what extent does a bulbs power have to do with total leaf size? Reason i ask is cause i went to a buddys house and hes running 600hps with a 400mh. The leafs on his plants are way smaller then mine. His biggest fan/energy leaf is only maybe 5in long. Under my 1k hps my leafs are huge, like dinner plate size. So just curious if you guys have noticed a stroung coralation between the two.

It's not the wattage of the lights. Even if he wasn't using the same total wattage as you, when growing the same plant as you, he'd have to use a light that was actually inadequate for a given plant for its biggest leaves to be noticeably smaller than yours at the same plant height. More light energy increases growth up to the maximum amount of light the plant can handle, of course, but if both different wattage lights are as close to their respective plants as they can be without light burn, then both plants are receiving similar amounts of light at canopy level. The higher wattage lamp just needs to be further away from the plants and will support healthy growth further down than the lower wattage one.

i think it has something to do with how much you feed your plant also.