Pro Cal is an excellent supplemental source of Calcium, Magnesium and Iron. Plants engaged in rapid growth can often come up short on these essential elements so supplementation is a great idea. The savvy grower makes Pro Cal a must have in their arsenal of plant growing weapons. Plants undergo a lot of stress and rapid assimilation of nutrients in their quest to build cell walls, produce chlorophyll, conduct photosynthesis, divide cells and other important functions. Calcium is an element that isn’t very mobile within the plant and needs good flow of fluid throughout the plant to pull it to the areas to which it is needed and more importantly the calcium needs to be in a form that the plant can easily transport. It is of no use if there is an ample supply of calcium but that the plant can’t uptake it. Pro Cal has solved this issue so that our calcium source is readily available and married with extra magnesium and fully chelated iron. Features: Thickens cell walls Helps form calcium pectate Fully chelated iron Important source of magnesium Noticeable size increase Improved enzyme function Coco coir approved Powerful formulation Cost effective