an hps burning the house down...not if u take precautions...but outdoors u don't need a greenhouse...dig big holes and fill with premium soil...start em in 8in. pots...when they're bout ft. tall put in some big ass holes...2-3ft wide and 2ft deep...u'll get huge harvest of gigantic buds if u follow this technique...i usually fill with mg moisture control potting soil so u don't got to worry bout watering often and the soil has plenty of food...feed em when they flower and boom...harvest some nice homegrown buds(without the $ spent on a greenhouse) :jointsmile: