tataceanswered grow question 8 months ago The belief that cannabis plants need a lot of phosphorus, however widespread, is not supported by scientific data which actually states that when in excess it significantly reduces the yield of the plants. I stay away from various supplements, I choose a good tripart and then I delve into Calcium, Magnesium, Silicates, Sulphur, Vitamins, Amino acids and possibly hormones (Natural, no carcinogenic chemical crap).