They argue that by allowing residents to grow their own marijuana, they would also be growing toxic black mold. “Stachybotrys mold needs four things to grow and turn into a deadly toxin known as Black Mold: Wood and other forms of cellulose such as plant matter, water, heat, and air,” says Alexandra Datig of nipitinthebud2010.org, “Stunningly, indoor marijuana cultivation offers all four.”