How To Add Calcium To Soil For Tomatoes

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Last Updated on October 26, 2022

Every gardener needs to learn how to add calcium to soil for tomatoes to ensure they are healthy fruits free from disease that hinders growth.

Have you noticed any small, water-filled patches at the bottom of the juicy red tomato that widened and turned into a dark patch?  On touching, did you notice how they give you a sunken and leathery feeling?  This tomato is suffering from blossom end rot – a common disease that prevents the proper growth of the plant.

This disease occurs due to a lack of calcium; therefore, it is vital to know the importance of adding calcium to plants.

Importance Of Calcium For Tomatoes

A healthy plant blossoms in rich soil.  Tomatoes require an adequate supply of calcium, nitrogen, phosphorous, and potassium for them to thrive.  Adding calcium to the garden in its soluble form is easy and enters the roots of your plants, making it easy for their absorption.

There are several reasons why you will need to add calcium to your garden before growing tomatoes.  They include:

  • Calcium is a macronutrient used quite as much as nitrogen, potassium, and phosphorous.
  • It is the macronutrient of plants.
  • It’s crucial to give proper health to plants and be involved with so many functions in plants, from appropriate cell wall formation to fruit production.
Importance of Calcium for Tomatoes

Plants need calcium throughout their growth period since it’s used in so many processes in the plant. Therefore, the ideal time to add calcium to the soil is throughout the plant’s growth period.  Of course, you can’t keep on adding calcium to your garden soil; but the time you add depends on you.

How To Add Calcium To Soil For Tomatoes

Test Your Soil

Before planting your tomatoes, it is advisable to conduct a soil test to know what nutrients are present and which ones are missing.  You can test the soil at home to determine the presence of macronutrients and soil acidity.  Calcium deficiency is revealed when soil is tested in a laboratory.  In extreme cases, you can get professional help to get advice on how to add calcium to your soil for tomatoes.

Add Ground Limestone And Gypsum

Lime and gypsum work well together and are good sources of calcium.  To increase calcium in your soil, add limestone by spreading it all over the soil.  Use a machine or hands to mix the soil and get it ready for planting.  Both lime and gypsum are coated with molasses, which is an excellent source of calcium.  The ground gypsum has inbuilt salt making it an excellent source of calcium.  Gypsum can have a lasting effect on the soil with nutrients like magnesium, copper, phosphorous, and zinc.  It should therefore be used in controlled amounts.

Down to Earth Organic Garden Gypsum Calcium Sulfate, 5 lb

Use Fertilizers

Soluble fertilizers can be a good source of calcium for tomatoes.  Other fertilizers like soft rock phosphate are naturally rich in calcium and intended for tomatoes used.  You can add these fertilizers when tilling it.  For tomatoes, be careful not to disturb their roots when giving the plants fertilizer.  Give them a one-time application of half a cup of 8-8-8 granular chemical fertilizer.   If using organic granular fertilizer, use only 1 cup of 5-5-5 per plant.  Mix this fertilizer with the top 8 inches of soil along with lime before planting your tomatoes.

Add Eggshells

Yes, you heard it right!  Eggshells are rich in calcium and can be added to the soil.  Grind them into a fine powder before integrating them into the soil.  Unlike limestone, it must break down into the soil before the plants use it. The breakdown process might take a few months.  This method remains one of the simplest and easiest methods to provide calcium to tomatoes.

Use Calcium Spray

You can spray the tomato leaves as a way to add calcium to these plants.  And the most significant thing of all is you can make this spray yourself.  Simply your choice of calcium solution to a gallon of water.  Shower or drizzle the solution once or twice a week when the flowers are set to bloom.  Ensure the spritz reaches the fruits too.

Water Your Plants Thoroughly

Water is the number 1 source of calcium.  An inch of water per week is required for the growth of juicy and calcium-rich tomatoes.  You can use rain or irrigation water to water your tomatoes. Note that these plants love to be deeply watered throughout, or else shallow watering will not improve the situation.  Ensuring you have provided your plants with adequate water is essential to provide calcium and feed the plants.

When you use any of the methods above, your plants will not suffer blossom end rot.  Pot-grown tomatoes are more prone to catching this disease than garden ones.  So ensure you supply enough calcium to the potted plants too.

What Happens When You Add Calcium To Soil For Tomatoes Early?

It is the best time to add calcium to your soil as it will begin to work and stabilize the soil before planting your tomatoes.  If your soil has a Ph level of 6.5 to 7.2, it is acidic and needs to be supplemented with lime.  You can also add dolomite lime to improve the level of magnesium in the soil.  If you forget to add lime early in the fall season, don’t worry; you can still add it in the spring season at least 2 months before planting tomatoes.

What Happens When You Add Them Late?

If you notice you are late to add calcium to the soil, it’s best to add it late than not at all. However, don’t wait until it’s too late because it will not work.  Adding lime can be a great solution to eliminate the acidity of the soil. 3/4th cup of lime is enough for each plant.

What Happens When You Add Them Late


Why is calcium important to tomato plants?

The calcium in your soil is essential for the growth of tomato plants. Calcium helps the plant to develop a strong and healthy root system and to produce flowers, fruits and seeds.

Calcium is often called "the muscle food" because it helps to build strong cell walls. The calcium in the soil can be used by the plants to build strong roots and stems.

You can get calcium from your soil and apply it to your tomato plants when you plant them. However, if you want to give your plants a boost of calcium, you can also feed them as they grow.

How do I add calcium to my tomato plants?

You can add calcium to the soil in the form of dolomite, limestone, oyster shell, or even rock dust. You can also add calcium to your tomatoes by using a foliar spray. Many home gardeners use a diluted solution of calcium chloride to feed their plants. If you do not have access to a spray bottle, you can purchase a fertilizer with calcium already mixed into it. Foliar feeding is done by spraying the leaves of the plant with a solution of calcium. If you want to know how much calcium you need to feed your tomatoes, you will have to experiment with different amounts.

Can calcium be harmful?

It takes time for your plants to get used to getting their calcium from the soil rather than from the leaves. So start by adding a small amount of calcium to your soil and see how your plants respond.

If you add too much at once, it will burn your plants.

How can I tell if my tomato plants need calcium?

Tomato plants are actually a very good source of calcium. In fact, the calcium content is so high that if you add too much calcium to your soil, it will inhibit plant growth. This is especially true of older plants. Soil tests are good at determining the calcium content of soil, but they can't tell you what the calcium content is in a specific plant. Soil tests can only tell you the calcium content of the soil as a whole.

What is the fastest way to add calcium to soil?

The most effective way to add calcium to soil is to use bone meal or manure. The best time to do this is in the fall when it is time to start a new crop, as it will improve the soil and provide nutrients for your crops. It is also better to apply bone meal than manure, because of the high amount of nitrogen in bone meal.


Now, you are well informed about how to add calcium to tomato plants; it’s high time you do so. To prevent the tomatoes from suffering from the blossom rot disease, ensure you add calcium to your soil at the right time.

When your soil is well enriched with the right amounts of nutrients, you can now thrive in your tomato farming.

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