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Calcium Nitrate Fertilizer – What Does Calcium Nitrate Do For Plants

Calcium Nitrate Fertilizer – What Does Calcium Nitrate Do For Plants


By: Bonnie L. Grant, Certified Urban Agriculturist

Providing the correct amount of nutrients to your plants is crucial to their health and development. When plants don’t have enough of a certain nutrient, pests, disease and low bearing are often the result. Calcium nitrate fertilizer is the only water soluble source of calcium available for plants. Read on to learn how to use calcium nitrate and decide if it will be useful for you in your garden.

What is Calcium Nitrate?

Diseases like blossom end rot are easy to control with calcium nitrate. What does calcium nitrate do? It provides both calcium and nitrogen. It is usually applied as a dissolved solution, allowing for quicker plant uptake but may also be applied as side or top dressing.

Ammonium nitrate is a commonly used source of nitrogen but it interferes with calcium uptake and causes calcium deficiency disorders in plants. The solution is to apply calcium nitrate instead to any crop that has a tendency to develop calcium deficiency disorders.

Calcium nitrate is produced by applying nitric acid to limestone and then adding ammonia. It is known as a double salt, since it is comprised of two nutrients common in fertilizers which are high in sodium. The processed result also looks crystallized like salt. It is not organic and is an artificial fertilizer amendment.

What does calcium nitrate do? It helps with cell formation but it also neutralizes acids to detoxify the plant. The nitrogen component is also responsible for fueling protein production and essentially leafy growth. Heat and moisture stress can cause calcium deficiencies in certain crops, like tomatoes. This is when to use calcium nitrate. Its combined nutrients can help cell growth stabilize and fuel leafy development.

When to Use Calcium Nitrate

Many growers automatically side dress or top dress their calcium sensitive crops with calcium nitrate. It is best to do a soil test first, as excess calcium can also lead to problems. The idea is to find a balance of nutrients for each particular crop. Tomatoes, apples and peppers are examples of crops that may benefit from calcium nitrate applications.

When applied early in fruit development, the calcium stabilizes cells so they don’t collapse, causing blossom end rot. Meanwhile, the nitrogen is fueling plant growth. If you are an organic gardener, however, calcium nitrate fertilizer is not an option for you since it is synthetically derived.

How to Use Calcium Nitrate

Calcium nitrate fertilizer can be used as a foliar spray. This is most effective in treating and preventing blossom end rot but also cork spot and bitter pit in apples. You can also use it to treat magnesium deficiencies when it is combined at a rate of 3 to 5 pounds magnesium sulfate in 25 gallons of water (1.36 to 2.27 kg. in 94.64 liters).

As a side dress, use 3.5 pounds of calcium nitrate per 100 feet (1.59 kg per 30.48 m). Mix the fertilizer into the soil, being careful to keep it off of foliage. Water the area well to allow the nutrients to start seeping into soil and get to plant roots.

For a foliar spray to correct calcium deficiency and add nitrogen, add 1 cup of calcium nitrate to 25 gallons of water (128 grams to 94.64 liters). Spray when the sun is low and plants have been watered sufficiently.

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Read more about Soil, Fixes & Fertilizers


Fertilizer Recipe Using Calcium Nitrate

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Calcium nitrate is the only water soluble form of calcium. Because it is also a source of nitrogen, it is commonly used in liquid fertilizer recipes to deliver both of these essential nutrients to growing plants. When nutrient deficiencies are noticed, apply calcium nitrate in complete fertilizer recipes or as a nutrient spray.


Calcium Nitrite Fertilizer Uses

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Calcium nitrite, made by mixing hydrated lime with nitrogen oxide gas, is not water soluble and is most frequently used to accelerate the hardening of concrete and to protect metals from salt corrosion. Additionally, calcium nitrite is necessary to make inorganic calcium nitrate, a component in many fertilizer formulations.


No, Epsom salt does not add calcium to soil. Epsom salt is magnesium sulfate, so it contains magnesium, sulfur, and oxygen (along with some water).

Epsom salt (magnesium sulfate) does not help to prevent blossom end rot in tomatoes or peppers, since it does not contain any calcium.

So, there is no way that Epsom salt can add calcium to soil, or do anything to prevent blossom end rot. For more information, check out my article on Epsom salt.


How to use Calcium Nitrate for Tomatoes

After you have mixed up your calcium nitrate solution you’ll be ready for spray application to your garden. For the best application method, wait until your tomato plants have grown to at least the second set of blossoms.

After you see these second set of blossoms, you can the apply your spray to the tomato leaves two or three times a week.

The second way to apply calcium nitrate to your plants is a side dressing directly into the soil. The amounts will differ. You’ll need about four ounces of spray solution for every seven to ten feet of tomato rows. You’ll mix your solution directly into the first one inch of surface soil, and avoid getting it on the leaves if you chose to do this method.

Other Uses of Calcium Nitrate in Garden

Calcium nitrate has many other benefits for the garden, and not just for tomatoes. Since all plants require calcium and nitrate nitrogen to grow, it can be a great fertilizer for the entire yard, including grass.

But there are many vegetables that are commonly grown in the garden, and the calcium nitrate can also suitable for them. All types of vegetables can benefit from using fertilizer, rather than nothing. These include broccoli, cabbage, cauliflower, celery, lettuce, and spinach. The recipe and application method is similar to the application for tomato plants.

Tips for Growing Tomatoes

Since tomatoes are a garden staple they can benefit from other growing tips to ensure that yours are the largest, and firmest, yet taste good too.

When you’re first planting your seedlings, don’t crowd them together. Ensure they have plenty of space from each other. Also ensure they are grown in a part of the garden that gets lots of light. Don’t plant them below a sun-blocking bush or tree. If you are growing them in a greenhouse or indoors, ensure you have adequate electrical lighting for them.

Indoor plants love a bit of a breeze, and this can be replicated by a fan. Before planting outdoors, cover the planting bed with a black plastic sheet. This will heat up the ground. Seedlings love soil warmth, and this will encourage them to grow faster. When you plant your seedlings, bury them deeper in the ground than when they were planted in their seedling pots. This encourages root growth. Many people like to bury their plants sideways. They’ll soon raise up as they grow toward the sun.

Don’t immediately mulch the ground. Do it after the ground has heated up. When your tomato plants have grown to a length of three feet remove the leaves that are from the ground and up to one foot. These are usually the leaves that will first develop fungus as soil-born pathogens will spray upwards. You can use a compost tea spray to prevent this.

Even soil that contains a lot of calcium carbonate, or lime, doesn’t necessarily mean that plants can utilize this form of the nutrient. This is why a good fertilizer such as calcium nitrate will provide the nutrients that your tomatoes and other vegetables in the garden need. The calcium carbonate in soil does not dissolve well in water, making calcium nitrate a better form of plant nutrient. Remember that if you’re using calcium nitrate to not use any other agricultural chemical on your tomato plants.

Keep your calcium nitrate in closed packages and in a dry, moisture-free spot in the garden shed. With some attention to detail, you’ll experience a better crop of tomatoes this year.


Watch the video: How to Mix our Calcium Nitrate Calcinit. Great for Veg Cycle growth