Calcium Deficiency in Plants: Common Reasons & How To Fix

Why Do Plants Need Calcium

Has your plant stopped growing? Or is it growing slower than usual? This might be a sign of calcium deficiency in your plants. Prolonged nutrient deficiency can lead to your plant becoming stunted and weak. Therefore, you have to fix this problem if you want it to live a long and healthy life.

Many people think that adding calcium to the soil can fix its deficiency problem. But, in reality, solving this issue isn’t as easy. Before we get into the possible solutions, let us look at why a plant needs calcium and the causes of its deficiency.

Why Do Plants Need Calcium?

Why Do Plants Need Calcium

In humans, the main work of calcium is to keep the bones and body healthy. Likewise, in plants, it upholds the strength of older leaves and helps the younger leaves to flourish. If calcium is not in the right amount, it can lead to discoloration of the plant and rotting of roots. 

Hence, the gardeners should use the right amount of fertilizers to keep the plant healthy. In addition, other factors like soil pH play a vital role in the optimal growth of plants.

Causes of Calcium Deficiency

By the name, you may think that calcium deficiency is generated by the lack of this essential nutrient. This is one of the primary reasons, but other factors play a vital role too. Even if the soil contains the right amount of calcium, it doesn’t mean that your plant will absorb all the calcium it requires. If the following factors are not in the right amount, your herbs and shrubs will suffer from calcium deficiency:


Most plants thrive when the pH of the earth revolves between 6 to 7. If the pH falls below 6, the soil will become acidic. This results in plants experiencing a troublesome time absorbing the essential nutrients. However, some acid-loving plants may be able to grow better in acidic soil.

Nutrient Balance

For this factor, we need to look at the chemical properties of calcium. Calcium is a metallic element, indicating that calcium is a cation, aka a positively charged ion. Hence, this positive charge reacts with a negatively-charged particle located in the clays and other organic matter.

The ability of the soil or other materials to retain the cations is known as cation exchange capacity or CEC. If you are into gardening, you may have come across this term. Usually, the denser substances like clay and organic matter possess a high CEC, whereas less dense materials like sand have a low CEC.

Calcium is not the only plant nutrient that reacts with other negatively-charged particles. Many essential metallic nutrients like magnesium, sodium, potassium, aluminum, and manganese bind with these sites. If one of the nutrients is in surplus, it can lead to a situation called over-saturation.

For instance, if magnesium is five times more in the ground than the amount a plant needs, most binding sites will get loaded with magnesium. A similar case happens when you add calcium in excess to the soil.

Transpiration Rate

Transpiration is a process by which water evaporates from the plant tissues like leaves and flowers. You may have learned about this in school. Even though the roots absorb water in large quantities, the majority of it is released back into the air through transpiration.

How Does This Relate to Calcium?

As you may know, plants have two primary tissue to transport water and minerals throughout their body. They are xylem and phloem. Phloem helps transport plant sap in multiple directions and consists of living cells. On the other hand, the xylem tissue transports water and minerals from the roots to the leaves. Xylem tissue comprises dead cells.

Calcium is a vital mineral that transverses through the plant via the xylem tissue. Therefore, its movement is related to the transpiration rate. When transpiration happens through the stomata present in the leaves, suction action pulls more water up the plant.

However, low transpiration rates can result in calcium deficiency because less water and minerals(including calcium) travel through the xylem. So, why do plants experience low transpiration rates? There can be many reasons, but the primary ones include insufficient water, high humidity, and cold temperatures.

Fixing The Calcium Deficiency in Plants

Fixing The Calcium Deficiency in Plants

Before discussing the fixes, you need to make sure that you use a calcium source soluble in water such as calcium nitrate. This allows the nutrient to get easily absorbed by the plant roots. If you use soil, which is most of us, calcium sources such as bone meal, lime, or gypsum are more suitable choices. However, it can change the pH levels of the earth or may add other nutrients as well.

If you prefer hydroponics to grow your plants, just add the calcium-only substance. This will ensure that you do not overdose your plant with other types of nutrients. If you use hard water, keep in mind that it already contains a high level of calcium and other kinds of nutrients. Hence, you may not need to add these nutrients.

In most cases, the plant just needs you to add more calcium to the earth when it suffers from calcium deficiency. However, adding more of this nutrient can generate other issues. It is even possible that the soil or solution does not require more calcium. The central problem can be something else. It can be due to a low pH level or temperature variations. Hence, we will need to look at these factors and see how we can fix them.


Water is essential for the roots to absorb nutrients from the soil. Without proper irrigation, plants will go into a state known as water deficit. This can further lead to many other problems. Hence, you need to build a schedule for proper irrigation of the plants.

pH Level 

The optimal pH level of the soil depends on what type of species you are considering. For instance, tomatoes like the soil to be neutral, whereas blueberries are acid-loving plants. If the soil is too acidic, you can use a base like lime to neutralize the soil.


As the temperature rises, the transpiration rates will also increase. Likewise, if your house garden is cold, the transpiration rates will decrease, leading to calcium deficiency. However, room temperature is enough for the optimal growth of most plants. Depending on the temperature variations, you can use either an air conditioner, cooler, or room heater.


If the humidity is high in your grow house, transpiration rates will decrease. You can fix this issue by adding fans to facilitate airflow and help the plant transpire. Regularly monitor the greenhouse environment to know any further problems.

Prevention is Better Than Cure 

Prevention is Better Than Cure

If you take preventive actions from the start, you will not have to go through so much trouble. Hence, a few measures you can take to protect your plants are: 

  • Make sure that there are no defects in the fertigation system
  • The nutrients should be given to the plants proportionately
  • The fertilizer stock solution should be kept and maintained in multiple tanks
  • Reservoirs should consist of consistent solution levels

For their optimal growth, plants need a variety of macro and micronutrients. This makes it difficult to treat a deficit caused by a single nutrient. Very often, your plant suffers from deficiencies of various nutrients at one time. 

Hence, it becomes essential to observe the fundamental parameters of plant health. This will help you in the long run as it is easy to identify an issue if you regularly monitor the plants. They will thrive in your garden instead of just surviving!

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