Detecting a Lack of Calcium in Gardens

Soil Testing

• Inexpensive soil tests sold in hardware stores and home improvement centers do not always test the amount of calcium in the soil. To determine whether your soil lacks calcium, have a soil test performed by a soil test service. The resulting soil test summary or soil analysis sheet will indicate whether your soil needs additional calcium and provide instructions for adjusting the calcium level.

Observation of New Growth

• Savvy gardeners may be able to detect a calcium deficiency from observing plant growth. The new growth on the plant shows signs of a calcium deficiency first. The young leaves and stems may appear stunted and the plant may take on a bushy appearance. New leaves may be small or misshapen and have brown spots along the margins. The spots eventually grow inward and meet in the center of the leave. Veins may appear dark and leaves may look crinkled or torn at the edges.

Observations in Fruiting

• In the case of tomatoes and peppers, a calcium deficiency may cause a soft, dark spot on the end of the fruit. This is referred to a blossom end rot. The soft area ruins the appearance of the fruit and may spread to include a large portion of the fruit. Typically, when blossom end rot strikes, it affects all of the fruit and can render the entire vegetable patch with infected fruit.

Dry Weather and Calcium Absorption

• Sometimes, a calcium deficiency in plants is due to a lack of water and not a lack of calcium in the soil. Because calcium dissolves in water and is then transported via the roots to the growing plant, when the soil is too dry plants do not receive the calcium they need to thrive. This is often the case with tomatoes and peppers that develop blossom end rot during dry seasons. In this case, the solution is regular watering to keep soil from over-drying.

Soil pH and Calcium

• Calcium and soil pH are directly related, as the concentration of calcium in the soil is the primary determinate of soil pH, according to Ohio State University Extension. As a rule, the higher the soil pH, the higher the calcium concentration in the soil. Thus, a low soil pH may indicate that your soil has low levels of calcium. If you suspect a calcium deficiency in your plants, adjusting the pH of the soil based on a soil test may be in order.