Calcium is considered one of the secondary nutrients for plants. Although it is not as essential as primary nutrients (nitrogen, potassium, and phosphorus), it still plays several important roles—such as enhancing nutritional value, protecting plants from microbes and pest damage, and supporting proper growth.
However, when calcium levels exceed the optimal range, several problems can develop in plants. In the following sections, we will discuss the symptoms of excess calcium, its causes, and how to prevent it.
Signs of Excess Calcium in Plants
An excessive buildup of calcium affects the plant’s ability to absorb potassium, magnesium, and iron. The deficiency of these nutrients results in symptoms that negatively impact plant health and growth. Below are the signs that indicate a plant is suffering from too much calcium:
1. Spots on Leaves
Excess calcium causes the appearance of spots on plant leaves, often reddish-orange in color.
2. Leaf Drooping
High calcium levels may cause leaves to droop slightly downward as a visible reaction to stress.
3. Stunted Plant Growth
Excess calcium affects the plant’s normal growth.
Under normal conditions, calcium is essential for forming strong cell walls and ensuring healthy development. When its levels become too high, its beneficial role is disrupted, leading to growth deformities or slowed growth.
4. Deficiency in Other Nutrients
Excess calcium reduces the plant’s ability to absorb magnesium, iron, and potassium. The most common symptoms include:
Iron deficiency symptoms
- Yellowing of leaf blades while the veins remain green
- Smaller, pale new leaves
- Severe cases may lead to leaves turning white with brown edges
- Noticeable reduction in overall yield
Magnesium deficiency symptoms
- Yellowing of tissues and veins
- Leaves may become deformed, fall prematurely, or die
Potassium deficiency symptoms
- Weak plant immunity, increased susceptibility to diseases
- Smaller and lower-quality fruits
- Drying of leaf tips and edges
Causes of Excess Calcium in Plants
Several factors can lead to calcium buildup in the soil, including:
- Overuse of calcium-rich fertilizers
- Adding lime to the soil without conducting a soil test beforehand
- Watering plants with hard water (high mineral content)
How to Prevent Excess Calcium in Plants
To avoid calcium toxicity, it is necessary to reduce soil calcium levels. Before taking any corrective action, a soil test should be performed to accurately determine calcium concentration. Recommended corrective practices include:
1. Planting Oxalate-Rich Leafy Crops
Growing crops such as spinach, which contain oxalic acid, helps naturally reduce excess calcium in the soil.
2. Adding Organic Matter
Use organic materials with higher acidity and lower calcium levels, such as:
- Decomposed leaves
- Organic compost
- Peat moss
3. Leaching Soil with Water
Water the soil once a week for 30–60 minutes to help flush out accumulated minerals.
4. Crop Rotation
Diversifying crops prevents calcium buildup and maintains soil nutrient balance.
