The medical pot growers are almost always grown in greenhouses from what I take. This is the article that peeked my interest last year. http://www.forbes.com/forbes/welcome/?toURL=http://www.forbes.com/sites/danalexander/2016/07/06/cannabis-capitalist-scotts-miracle-gro-ceo-bets-big-on-pot-growers/&refURL=https://www.google.com/&referrer=https://www.google.com/