a good one I heard from a friend, a mutual friend of us told this to him and was truly convinced it was true, that friend didn't believe it and asked me since I grow and in the eyes of my friends I know everything about weed(one of my nicknames is the weedencyclopedia)
according to him you should inject a growing alive weedplant with heroin(with a syringe, in the stalk/mainstem), wich should be good for the plant and make it give huge yields.....