Magnesium is leached by watering and must be supplied when feeding. It can be applied as a foliar spray to correct deficiencies. Calcium activates enzymes, is a structural component of cell walls, influences water movement in cells and is necessary for cell growth and division. Some plants must have calcium to take up nitrogen and other minerals. Calcium is easily leached.
Deficiency causes stunting of new growth in stems, flowers and roots.
Symptoms range from distorted new growth to black spots on leaves and fruit. Yellow leaf margins may also appear. Micronutrients Iron is necessary for many enzyme functions and as a catalyst for the synthesis of chlorophyll. It is essential for the young growing parts of plants. Deficiencies are pale leaf color of youn g leaves followed by yellowing of leaves and large veins.