POLY4’s four macro nutrients, as stated on its label, are 14% K2O, 17% CaO, 6% MgO and 19% S*.
Label declared analysis of a fertilizer is the minimum content of its nutrients or, in the case of undesirable elements, the maximum content of that element. It is most commonly expressed as a percentage by weight.
- POLY4's chemical formula
- K2SO4 MgSO4 2CaSO4 2H2O.