Calcium Fertilizers
The Different Types of Calcium Fertilizers & How they Impact the Soil
As calcium is an integral macronutrient found in the soil, you may need to use a calcium fertilizer if your soil is deficient.
Here, we look at the different types of calcium fertilizers that you can use and how they alter the soil in different ways, including their impact on the soil’s pH level.
Calcium in soil – why it’s important
Calcium is a macronutrient found in soil. While plants require more potassium, nitrogen, and phosphorus for their growth, calcium is still an integral nutrient, as it makes plants less susceptible to disease.
That being said, it’s important to get the balance right. Adding too much calcium to your soil can make it too alkaline, which makes it less absorbent of other macronutrients.
Before adding any calcium fertilizer to your soil, it’s a good idea to arrange a professional soil test. This is the best way to determine whether your soil is deficient in the first place.
Note that a professional test is different from a simple pH test that you can do for yourself, as it records both the calcium level and the pH level of your soil.
Understanding the CCE before using a fertilizer
The reason you need to do a professional soil test is to understand the Calcium Carbonate Equivalent (CCE).
The higher the CCE of the soil, the more calcium is available to the plants within it. Let’s take a look at some of the different fertilizers you can add to the soil to increase its CCE.
The different types of calcium fertilizers
As calcium is a key element for the healthy growth of plants, calcium fertilizers can promote the strong and healthy growth of numerous plant species.
But as mentioned above, you need to first determine whether or not your soil is calcium deficient before adding a fertilizer, as you don’t want to risk making your soil too alkaline.
After the soil test, there are numerous ways to add calcium to your soil, with the following calcium fertilizers all worth considering:
Lime – Best for its high CCE
One of the easiest and most cost-effective ways to increase the calcium in soil is to add lime. Also known as calcium carbonate, lime increases the pH level of your soil, so add it in moderation if you plan on using it as a fertilizer.
Dolomitic lime – Best for calcium & magnesium deficient soil
Dolomitic lime contains magnesium carbonate, and it’s a particularly good option if your soil is low in magnesium. You will find out the calcium and magnesium levels via the professional soil test, so this is a good option if it is deficient in both nutrients.
Gypsum – Best for sulfur & calcium without altering the soil’s pH level
One of the biggest advantages of adding gypsum to soil is that it doesn’t change its pH level. It is a calcium sulfate that acts fast and helps your plants get the nutrients that it needs to grow healthily.
Bone meal – Best for phosphorus & calcium
Another good alternative to lime is bone meal, which is a slow-release calcium fertilizer. People who grow bulbs and root crops often use bone meal, as it is less soluble than lime, and it only slightly raises the pH level of the soil.
Wood ash – Best for a natural alternative to lime
Hardwood ash is a good natural option when it comes to adding calcium to your soil. One of the drawbacks is that you need a lot of wood ash for it to have the intended benefits, and it’s not as effective as lime.
Colloidal phosphate – Best as a slow-release calcium fertilizer
Sometimes referred to as rock phosphate, colloidal phosphate slowly releases calcium into the soil. It also moderately raises its pH level.
Which is the best calcium fertilizer for plants?
Dolomitic lime and limestone have CCE values around 100, making it one of the best options for the soil. However, you need to be mindful of the fact that lime significantly raises the pH level of the soil.
In comparison, gypsum has a reading of around 25 CCE, but it is a good option because it doesn’t change the pH level. Bone meal tends to have a CCE of around 20 to 30.
The key thing to remember when adding a calcium fertilizer is that calcium isn’t the only essential nutrient for your plants, so getting the balance right is absolutely key.
How do calcium fertilizers affect the soil?
As you would expect, calcium fertilizers affect the soil by increasing the CCE. However, they also alter the pH level of your soil, so you need to consider which type of fertilizer to use.
So, follow these steps to determine which type of fertilizer to use:
- Complete a professional soil test and a pH test to get a reading of which nutrients your soil needs.
- Consider which plants you have or which plants you are going to plant and how they will respond to the addition of each calcium fertilizer.
- Select a calcium fertilizer that will help the growth of your plants and apply it in moderation so you don’t drastically alter the pH level of the soil.
Conclusion
Calcium is a key nutrient in soil and it contributes to the healthy growth of plants. Lime is the most commonly used calcium fertilizer, but it significantly alters the pH level of soil and needs to be used in moderation.
Therefore, gypsum is a great option, even if its CCE is lower, as it doesn’t change the soil’s pH level and it can be used to support the healthy growth of numerous plant species.
Sources
https://www.groworganic.com/blogs/articles/how-to-use-fertilizers-calcium
https://www.thespruce.com/adding-calcium-to-soil-4773599
https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/calcium-fertilizers
