I agree with Booch but i dont think youd ever need to trim it especially if its only 7" tall. I'd have to assume that whereever your growing it that your space might be small in area but doesn't have AS MUCH as a restriction in height. A lot of people I know grow their stuff in really thin but tall places and make their plants stretch to cope for the lack of horizontal space. You COULD keep it short but that would be more for a purpose of learning or to not need such a large yield.