Learn how to add calcium to soil for healthy plants and how to know when your garden needs it. We’ll look at the top 13 ways to do this for the healthiest garden produce.
In This Article
Why Add Calcium to Soil
Calcium is an important macronutrient for healthy soil. It produces vitamin rich produce for your body’s needs to help keep you healthy and active.
The levels need to be right for plants to have what they need to avoid disease and pests. Just as it’s important to our body systems, it’s as important to the life of your garden plants.
Too much can lead to high pH levels. This will keep plants from being able to absorb macronutrients making a garden look puny and produce very little, if any, fruit.
Testing Your Soil
A pH test can indicate if you need to adjust calcium levels and a refractometer can tell you the Brix level of your produce. This will help you quickly know how well your plant is able to absorb nutrients.
If you want real numbers and percentages the easiest way is to get a comprehensive soil test from a professional lab. This will give you a good idea of what steps you need to take to make your garden a growing paradise.
You should see the difference as you give your soil what it needs. The super soil recipe provides all the nutrients your soil needs and can last for years.
Ideally, Ca is absorbed by the plant roots and moved by transpiration throughout the plant to provide overall health. This only works if it is present in your soil and the plant is able to absorb and use it.
The Cation Exchange Capacity (CEC) is the ability of the dirt to absorb and hold nutrients in the form of positively charged ions or cations.
A test of your planting dirt will tell you the level of your CEC. Organic matter and clay levels will hold water better than a sandier garden plot which will leak nutrients faster and fail to hold proper nutrients levels for a good CEC.
When to Add to Soil
By knowing the common signs of a deficiency, you will be able to quickly correct the problem. The faster you address the need, the better the chance you can prevent permanent plant damage.
You should be able to spot a deficiency in your garden by looking at the plants you have growing. As soon as you see any of these signs, you may want to have a soil test done or you can simply amend the soil to get a head start.
Signs of Calcium Deficiency
- Stunted growth
- Curling of leaves
- Brown spotting on leaves
- Inhibited bud growth
- Dead root tips
- Cupping of mature leaves
- Chlorosis (yellowing of leaves)
- Leaf tips look burnt
- Fruit damage such as blossom end rot
Top Ways to Add Calcium to Soil
- Epsom Salt
- To apply Epsom salt, it is best to add about 1 Tbsp to a gallon of water, mix thoroughly, then spray it on your plants. Spray in the early morning before the sun is on the plants so it has time to dry to avoid burning them.
- You can also sprinkle it on top of the ground and water thoroughly. It will dissolve and become available for plants. It will also help improve the uptake of critical nutrients like nitrogen and phosphorus. This is my preferred way of adding Epsom salt.
- Gypsum (Ca sulfate)
- Gypsum is a fast-acting Ca supplement with low CEC and it will not effect your pH levels. This is what the old timers used to amend their plots and is still a great choice.
- Calcium Spray
- You can buy foliage calcium sprays for a quick and easy remedy but as they do not address the need of the soil you will need to apply them every few weeks.
- Chamomile Spray
- Steep chamomile tea, or blossoms in boiling water until it’s cooled. Strain the tea and keep the leaves or blossoms to add to the garden area. Add the tea to a spray bottle and spray foliage of plants. Depending on your needs I would start spraying plants once a day until I saw an improvement. It is a organic option that works with many applicants.
- You can also dissolve chamomile powder in warm water, let cool and pour onto soil.
- Add seaweed to rainwater barrel or barrel about that size to around 10-20% of capacity then fill the barrel with water. Let it steep for 14 days. You can work the removed seaweed into the garden if you want. Put the water into a spray bottle and spray directly onto foliage.
- You can also mix the seaweed into the dirt between the rows of your plants or to potted plants and water thoroughly. This will add Ca over time.
- It’s easy to purchase an organic seaweed fertilizer at your garden center or online.
- Calcium Fertilizers
- Depending on your garden health, pH level, and the time of year, you may have to apply more calcium fertilizer than recommended to some types of plants.
- Lime (Ca carbonate mined limestone)
- Adding lime to your soil is a great way to boost calcium and raise soil pH.
- Dolomite Lime (Ca carbonate)
- Dolomite lime will also put magnesium into your dirt and may be a great choice for gardeners with low levels of both of these. If you don’t need magnesium, simply choose another option to raise your Ca or pH levels.
- Ground Oyster or Clam Shell Flour (Ca carbonate)
- Ca carbonate is a long term approach to amending your soil. The low solubility makes this a slow release option over 3-5 years. It will gently raise your pH at the same time.
- Wood Ashes (Ca carbonate)
- Wood ash is a great homestead product that all fireplaces, wood stoves, and brush piles produce. It will raise your levels and as long as you don’t burn any wood that is soaked in chemicals, is a cheap and easy organic amendment. Simply mix your wood ash into top 3 inches off your ground and let the water take it from there.
- Rock Phosphate or Colloidal Phosphate (Ca oxide)
- Calcium oxide releases Ca into the soil slowly and is not the easiest or cheapest option for most people.
- Bone Meal
- Bone meal is a high-phosphate fertilizer that is slower than some but a stable, dependable option for amending the levels over time.
- Egg Shells
- Egg shells decompose too slowly to be directly added to garden plot. They should be decomposed in a compost pile or worm bin before adding them to the garden so they will be able provide it.
- We save our egg shells and crush them for powder to use in the garden and to offer them to the flocks.
If you have not been gardening long or in the same gardening zone for any real length of time, you may want to take the time to get to know your soil. Every garden spot is different even on the same piece of land.
Before you start amending it, it’s best to consider what it actually needs.
You don’t want to cause more problems by adding too much of something. This mistake may be hard to correct in the years to come.
Now you understand the top ways to add calcium to soil, why you may need to, and how to know when to add it. Consider the ways to accomplish it and decide which works best for you goals and garden.
As always, we’re here to help.