Green Industry Is The Lose May 8, 2013 0:12:52 GMT -5 Quote Select PostDeselect PostLink to PostMemberGive GiftBack to Top Post by Rasteroid on May 8, 2013 0:12:52 GMT -5 I think the manual is pretty clear.. greenhouses work like production buildings for negative PM (strikes), but they get a multiplier on food produced for positive GM. (Like mines, for positive PM.)