Symptoms
Ca deficiency symptoms first appear on youngest leaves. They become light green, and tips and margins become necrotic.
Furthermore, the leaves are bent downwards like claws, the growing point dies off. The older leaves remain dark green.
Reasons
Calcium deficiency
Several nutrient deficiencies such as sulphur and iron start with chlorosis on younger leaves, but the claw-like shape of the leaves is characteristic for Ca deficiency.