Actually, the relevant questions may be -
What kind of lighting is he using? Fluorescent? Metal-Halide? Or a bunch of ultra-bright 5w Luxean LEDs?
And appropiate fertilizer? The sort you'd use, on say, tomatoes? Beans?
Are the pots clean to start with? What potting mix to use?

And for those who're posting about books and hydro kits, well... not all of us even know where to find the stuff. We're all newbies at times.