Plants require calcium for proper growth because calcium is essential for the development of strong cell walls. The element is also used in cellular signaling, a biological process critical to a plant's healthy development.
Generally, plants absorb calcium from soil, and it is rare for a plant to have calcium deficiency. When too little calcium is available to a growing plant, disorders can develop, such as those that result in damaged lettuce tips or burned tomatoes. Too much calcium in the soil can be harmful to a developing plant, leading to issues such as deposits of calcium carbonate crystals in plant parts.