Effect of Pre-Harvest Calcium Sprays on Calcium Concentrations in the Skin and Flesh of Apples

During 2004 and 2006, experiments were conducted that measured the absorption of calcium (Ca) by the fruit and assessed the effects of Ca sprays on the skin and flesh of apples. Frequent (1 spray/month for 2 or 4 months) Ca treatments increased the concentration of Ca in the skin, but not in the flesh of fruit, and several sprays were needed to promote a prolonged increase in the concentration of Ca in the skin. Calcium sprays did not influence the concentrations of magnesium (Mg) and potassium (K). Foliar analyses confirmed the absorption of topical Ca by the apple tree following the Ca sprays as the concentration of Ca in leaves increased.