Potassium works along with Nitrogen so if you add nitrogen to the soil, it is important to add potassium at the same time. Most soils already have some potassium, so the third number in the fertilizer analysis is usually smaller than the other two. Fertilizers for some tropical plants, especially palms, contain extra potassium because these plants have a special need for it. Calcium also helps to build cell walls. As it is contained in Chlorophyll, it is also important in the dark green color of plants and for the ability of a plant to manufacture food from sunlight.
Sulfur is needed to manufacture Chlorophyll.
It is used by the leaves and needed by legumes to form seeds. All Rights Reserved.