Calcium is an essential element in all vegetative growth, lack of calcium is very often one of the main problems for many vegetable gardeners. One of the most apparent signs of a calcium deficiency is what is called blossom end rot in tomatoes. Fruiting and root crops require an regular AND available source of calcium. Talborne's Bone Phos is a highly available sustained release calcium source that will not burn your plants. Apply to new plantings and work into the soil.