how important is ventilation??? i have three little guys growing right now with no ventilation... they are about 3-4 inches tall... should i add some ventilation to my grow rom now??? or what till they get bigger??? or forget the whole idea altogether??? my grow room is in a box... and adding ventilation would mean cutting out a piece of that box making it less light proof??? so all in all .... is it worth it? if so... how much for three plants?