Well im 4 weeks into a new grow right now same setup as before, im at about ,let me find my tapemeasure, jsut under a foot an a half, i would def. say it would be bigger if it were under a mh bulb but i dont have the money to throw into a new bulb just yet, so i cant really expirement. This i feel is a dedication type question, Its like aero or drip, they both work ones better tho. I think the real question is in the quality and not quantity, how much better will ur buddies be with a mh bulb in veggie. Its jsut a question of how much more u will grow i think. W/ lights regarding mh in veggie.