8 Ways To Add Calcium to Your Soil - Backyard Boss
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8 Ways To Add Calcium to Your Soil

There are many ways in which you can ensure that you have soil that will help your plants grow well and give you a very good yield. One of them is to make sure that it contains enough calcium. The easiest way to check this is by learning how to test your garden soil and using a home soil test kit which will let you know exactly what your soil contains and what it needs to be optimal for what you are growing. Here’s a detailed guide to help you learn how to use a soil test kit to boost your soil health.

But why calcium (Ca) specifically? Well, it typically contributes to soil fertility and good aeration. Moreover, the lack of Ca can lead to high soil acidity which will obstruct your plant growth. On top of it all, Ca is required for the forming of strong membranes and cell walls in plants. Down below you will find all about the benefits of calcium to your soil and plants, some ways to tell that there’s a deficiency of Ca, as well as some ways to add Ca to your soil.

How Calcium Affects Plants

woman mixing soil
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There are many benefits that calcium can bring to your backyard and some of them are:

1. Healthy Soil

Ca plays a crucial role in maintaining the soil pH. Moreover, it helps by opening up the soil, which itself leads to better water absorption and erosion reduction. Furthermore, this means that nutrients are easier to be absorbed by your plants.

2. Plants Get Nutrien

As we mentioned above, better aeration allows for nutrients to flow from the roots of a plant, through its stem, to every single leaf.

3. Early Season Growth

Another effect that Ca has on plants is faster growth at the start of the season and an amassment of a greater root mass. Furthermore, it assists with plant uniformity, which is a very important factor for crop growers.

4. Healthy Plant Tissue

Ca is a very important component of cell walls. Furthermore, it is key for cell division, nitrogen usage, and permeability of cell membranes. However, there’s a tricky detail – your soil needs calcium, while your plants need available calcium. Thus, you will need two different types of Ca – a soluble one and a slow-release one.

5. Better Yield Size

One of the best-known benefits of calcium is its help with yield size and quality. Especially when combined with alfalfa.

Signs of Calcium Deficiency in Plants

incorrect sunlight can curl plant leaves
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A good amount of calcium in your soil will help the growth of the young leaves of your plant, while at the same time maintaining the health of the old ones. However, if there’s a calcium deficiency, leaves will start to lose their color and rot will occur both above and below ground. This is why you should always keep close attention and take immediate action if any of the following occur:

1. Rot

Rot can occur anywhere on your plant – the leaves, the fruit, the stem, and the roots. This is a telltale sign of calcium deficiency, and it is crucial that you act immediately to avoid necrosis.

2. Decoloration

The loss of color to any part of the plant is a red flag. However, when it is due to Ca deficiency, brown spots will appear mostly on the leaf margins. Moreover, yellowy spots combined with them are an even bigger sign. You will have to act quickly in order to stop your leaves from becoming necrotic. Do remember that apart from Ca deficiency, there can be many other reasons for decoloration, this is why you should always perform a soil test first – this will help you find the root of the problem.

3. Curling leaves

When the plant doesn’t receive enough calcium, the new growth starts to curl up. If you notice this, especially with new leaves, it is a good idea to consider if the lack of Ca is the reason.

4. Slow growth

If a plant lacks Ca, it will take much, much longer to mature. While this can be a symptom of many issues, it is a good idea to rule out calcium deficiency first.

8 Ways to Add Calcium to Your Soil

So, in order to spare you the stress and time of looking for ways to add calcium to your soil, down below you will find the 8 most popular ways to do so:

1. Calcium Fertilizer

calcium for soil

Using soil additives is perhaps one of the quickest and easiest ways to do this. However, it is crucial that you check your soil pH level. Moreover, do make sure that you follow the instructions on the packaging so that you get the optimal effect.


Alternatively, you can view it on Amazon.


2. Add Lime During Fall

Woman gardeners put lime or calcium
Image credits: Tevarak via Canva

Lime is an excellent additive, especially if you opt to use it in the fall. Firstly, it can help with increasing your soil’s pH level and make it more acidic. Moreover, it will give your soil and plants a fantastic calcium boost. That said, if your soil is too acidic, it can make it difficult for your plants to grow. If you find out that your soil lacks magnesium too, you should use dolomitic lime. But always do a soil test first.

3. Use Eggshells

eggshells in plant
Image credit: ThamKC via Canva

Eggshells contain a massive amount of calcium, useful for a lot of plants. They have to be properly dried, made into a powder, mixed with water (3 tbsp eggshell powder per gallon of water), and administered through watering. Although they contain some of the best soil amendments and nutrients, they are not the quickest method. It can take about a year for some plants to take in the calcium contained in the eggshells completely.

4. Foliar Application

spraying and misting plant
Image Credit: Sasha Kim via Pexels

This is perhaps the fastest way to fight acute Ca deficiency. This is due to plants absorbing nutrients best through their leaves, rather than roots. Foliar sprays can be easily made at home using seaweed or chamomile and they will cost you almost nothing!

5. Apply Gypsum

gypsum powder

Gypsum is an amazing way to stabilize your soil pH. It is a supplement that acts quite fast and will not increase or decrease the pH level. Make sure that you spread the gypsum evenly over the soil of your backyard, then water it. Ensure you read the package instructions carefully before applying it to your soil.


Alternatively, you can view it on Amazon.


6. Ground Oyster Shells

oyster shells
Image Credit: EEPaul via Creative Commons

Oyster shell flour is another organic and easy way to add calcium to your soil. Unfortunately, it has a very low solubility. This means that before it is fully absorbed and effective, years will have passed. To make oyster shell flour, you have to dry the shells well, and then use a processor to make them into a fine powder. Spread the powder over the soil, then add a little bit of water.

7. Wood Ash

wood ash
Image Credit: ravi khemka via Creative Commons

This is an excellent calcium source, especially if it is hardwood ash. However, it does tend to increase the pH level significantly but is less effective than lime in this property.

8. Bone Meal

It is made out of finely ground-up bones and is a fantastic additive for raising Ca levels. However, it works really slow and it will take more than a full growing season before it’s reached its full potential.


Alternatively, you can view it on Amazon.


In Summary

There are many ways to add more Ca to plants and above we mentioned the eight easiest and most popular ones. While the symptoms seem quite simple and the diagnosis seems easy to make, before deciding on a Ca deficiency treatment, you should always use a soil test just in case this is not the issue.

Happy Gardening!

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