Calcium often appears in the cell walls and membranes and plays a special role in the ion-reactions within plants. Calcium is transported in the plant by means of water conduction (xylem). In situations with a high humidity or in a compact crop the rate of conduction is small and can lead to a deficiency of calcium. A deficiency of calcium leads to softened cell walls which manifests itself immediately in an increased sensitivity to fungi, and the dying off of young leaves and growing points. Also an excess of calcium can occur, which results into brown spots on the leaves. -Ca 15 works very fast, does not change the pH-value, and is a pure product. -Ca 15 is economic and contains 180 grams of pure lime per litre of liquid. -Ca 15 can be combined with all fertilization schemes, does not clog or pollute. A dosage of 1:1000 increases the amount of Ca by 3.2 mmol.