Is CAN Fertilizer Good for Tomatoes?

CAN fertilizer is a potent fertilization tool, and many farmers utilize it for calcium-loving crops. Unfortunately, despite its high levels of calcium and nitrogen, CAN fertilizer lacks vital ingredients necessary for most plants. So, what about tomatoes, do they like CAN fertilizer? 

CAN fertilizer is good for tomatoes because of its high calcium content. However, you must be careful when applying CAN fertilizer as it is also high in nitrogen and low in other vital nutrients. Therefore, CAN fertilizer should not be the only fertilizer used for tomato plants.

In the rest of this article, I will discuss what CAN fertilizer is, plants that benefit from its use, the pros and cons of applying it, what nutrients tomato plants need, and the best fertilizer to use on them. So if you want to learn more about CAN fertilizer and tomatoes, read on. 

What Is CAN Fertilizer?

CAN Fertilizer is a commonly used fertilizer among gardeners. There is a good chance that you have come across this fertilizer in your gardening research, especially if you are planting large-scale plant growth. Before using CAN fertilizer in your garden, it’s essential to understand what CAN fertilizer is and how to correctly use it.

CAN fertilizer is Calcium Ammonia Nitrate, an inorganic mineral that gardeners can add to the soil to provide a steady supply of nitrogen for plants. However, it can easily cause root burn if you don’t test the soil before its addition. In addition, too much nitrogen can be harmful to plants. 

Because limestone and nitric acid are the two main ingredients in this fertilizer, it is primarily composed of calcium and nitrogen. Additionally, it is water activated. CAN Fertilizer is best used on soils with low acidity as it tends to raise these levels once applied.

Plants That Enjoy CAN Fertilizer

Now that you have a better understanding of what CAN fertilizer is and how it functions, let’s discuss some of the many plants that benefit from its use.

Plants that can benefit from high levels of nitrogen:

  • Tomatoes
  • Peppers
  • Eggplant
  • Rhubarb
  • Brussels sprouts
  • Kale
  • Bok choy
  • Lettuce
  • Spinach 
  • Sweet corn 

These plants will all do well with a steady supply of nitrogen. However, it’s still essential to perform a soil test before applying a fertilizer like CAN, as it can significantly raise the nitrogen content in the soil. When nitrogen becomes too high in the soil, it can result in the overproduction of leaves and the underproduction of fruit. 

Root burn may also occur, causing the death of your plants, so it’s best to know your soil’s nutrient levels before fertilizing. This is especially important when using this fertilizer on tomatoes as they can get too much nitrogen but will still greatly benefit from the calcium. 

How Tomatoes Benefit From CAN Fertilizer

Tomatoes are a fantastic food source, rich in folate, vitamin C, and potassium. It’s a highly versatile food with dozens of uses, including sauces, salsas, stews, soups, and more. These delicious, acidic vegetables can be found in almost every home garden.

Unfortunately, tomatoes can also be quite challenging to fertilize as their needs change throughout their growth cycle. However, using a slow-release fertilizer to maintain their health is a great way to produce large delicious tomatoes. 

Tomatoes need calcium and nitrogen along with other nutrients in order to thrive. However, CAN fertilizer can be beneficial to tomatoes because it can help fend off blossom rot and prevent the spread of other tomato plant diseases. 

The Pros and Cons of CAN Fertilizer

Next, I want to discuss the many pros and cons of using CAN fertilizer on your garden plants. As I previously explained, this type of fertilizer is exceptionally potent and does a great job of releasing a steady supply of nitrogen into the soil. However, there are both pros and cons to using it. 

The pros of using CAN fertilizer:

  • Provides a steady supply of nitrogen for plants.
  • Slow-release nutrients for a more extended period of time. 
  • Aids in stronger plant growth. 
  • Promotes larger, healthier fruit. 
  • Helps prevent blossom rot. 
  • Provides a growth boost for plants. 

The cons of using CAN Fertilizer:

  • Improper nutrient supply for most plants. 
  • It is technically a synthetic fertilizer. 
  • It is difficult to apply evenly throughout the soil. 
  • Causes increased acidity in the soil. 

If you plan on using a CAN fertilizer on any type of plant, for example, tomatoes, be sure to test the soil before adding it in. 

If you don’t already have a soil tester, I recommend Luster Leaf’s 1602 Soil Test Kit (available on This kit is great because it provides rapid nutrient level results and comes with over 20 tests. Plus, it’s perfect for beginners to use. 

How Do You Use Calcium Ammonium Nitrate Fertilizer?

Now that you better understand CAN fertilizers’ effects on the soil and plants, it’s time to talk about how to apply it. When applying any type of fertilizer, it’s essential to read the instructions for the brand you are using. Each product will have different potencies; therefore, different amounts will be used to distribute it. 

You can use calcium ammonium nitrate fertilizer by mixing the granules directly into the soil or by creating a spray to mist your plants. Both will aid in increased plant growth and keep unwanted illnesses and pests at bay. Just be careful not to add too much.

If you are mixing the granules straight into the ground, be sure to follow the package’s directions. If you plan to make a calcium mist solution for your tomato or other plants, you should mix about four tablespoons of the salt into a gallon of water before transferring the mixture to a spray bottle.

Once wholly dissolved, the spray can help prevent blossom rot and keep your tomatoes safe from bugs and unwanted illness. Not to mention it can aid in healthy tomato plant growth. 

Luckily this type of fertilizer isn’t terribly smelly, but the scent can last a few days, so you should wear a facemask when applying it in large quantities. Chemical fertilizers are never good to breathe in.

What Nutrients Tomatoes Require for Optimal Growth

Now that you know more about using CAN fertilizer, it’s time to talk more about tomatoes and the nutrients they need. Tomatoes, of course, tend to become large leafy plants (depending on the variety) and need a good amount of nutrients to produce healthy fruit. 

Nutrients tomatoes need to thrive:

All these minerals, along with healthy soil, will ensure the growth of your tomato plants. CAN fertilizer contains two of these components, so it can make an excellent addition to your tomato plants’ soil. However, CAN fertilizer should never be used on its own since your tomatoes still need potassium and phosphorus to grow appropriately. 

When Should Tomatoes Be Fertilized?

Lastly, when using any sort of fertilizer, it’s essential to know when to apply it. For example, tomatoes are relatively simple to grow, but their fertilizing needs can be complex. So how often should you fertilize tomatoes? How can you tell when they need it? 

Tomatoes should be fertilized when planted and at different stages of their growth cycle. When tomatoes produce fruit, they need to be re-fertilized using a less aggressive fertilizer. You should fertilize your tomatoes until they die off in the winter weather. 

Use an all-inclusive fertilizer when you first plant your tomato plants. After which, if you wish, you can add a calcium-rich fertilizer like CAN fertilizer or a compost mix to ensure optimal plant growth. Just be sure your soil can handle the extreme acidity before doing so. 


Ultimately CAN fertilizer can be excellent for your tomato plants if used properly. However, you should use caution when applying it as it’s high in nitrogen which can cause explosive plant growth but also make plants sick in high doses. The high calcium content of CAN fertilizer is the most appealing to tomato plants as they rely heavily on this nutrient for growth. 

When using CAN fertilizer, it’s better to start with small amounts and add more if necessary. Of course, you can always add fertilizer but removing it is far more tricky. 

You can read my other article on how to fertilize indoor and outdoor plants here: How to Fertilize Indoor & Outdoor Plants (Ultimate Guide)

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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