Lack of calcium is seen as a downward buckling of leaves. Calcium deficiency shows up as a light green band on the margins of younger leaves. Leaves look wilted and the top of the leaves can remain unfolded. It is considered immobile, so calcium deficiency shows up in the youngest leaves and the youngest portions of the leaves. Young leaf margins curl back with brown spots.
Dead spots can appear on potatoes in the youngest tissues.
Calcium has an indirect role in plant nutrition by altering the availability of certain nutrients and preventing toxic effects from others. Plants need a steady supply of calcium as they are developing. Calcium and magnesium deficiency may appear on plants grown in highly acid soil, when excess aluminum is available for plants. Blossom End Rot - Brown spots that form on the blossom ends of fruits, especially common in tomatoes. Remedied with a calcium nitrate spray, made of calcium nitrate and water.