sry, that is one question that cannot be answered.
it depends on too many factors...
how good you are at growing.
the strain you're attempting to grow.
what type of set-up you have.
type of lights.
nutrients...
and on, and on....
might I suggest you try a less general question.
about lights or strains or growing methods.
Lol, I'm warning you; people are just gunna rip the piss out of a question like that. And it can be any where between a couple grams a swag and pounds and pounds of leng...depends on alot of things.
How are you growing it, what lights are you using, how long do you plan to veg it, how much room do you have, are you gonna use ferts, what kind, hydro or soil, what strain do you plan to grow, you gonna grow outside?