Homemade Calcium for Tomato Plants – DIY  Solutions

Calcium is one of the crucial minerals for tomato plants. It plays a key role in improving fruit quality. In most cases, plants obtain calcium from the soil but experts recommend spraying tomato plants with a calcium solution two to three times a week, beginning when the first blooms appear. 

Adequate calcium helps prevent several tomato disorders majorly Blossom End Rot. This is a physiological condition that causes the blossom end of the fruit to rot. So, calcium will act in strengthening cell walls in tomato plants, reducing the risk of cracking and splitting. 

Early application of calcium has also shown to reduce damage from caterpillars including tomato hornworms. The nutrient is also beneficial in root development and absorption of nutrients from the soil.

Calcium deficiency in tomato plants

Several factors can contribute to calcium deficiency in tomato plants. Inconsistent watering, especially underwatering is the main culprit. Understandably, water helps in the transportation of nutrients and mineral salts in the plant. So, underwatering typically disrupts the uptake of calcium by the plant. 

Blossom end rot is the most common symptom of calcium deficiency in tomatoes. It is a physiological disorder that causes brown, leathery rot near the blossom end of the tomato. While BER isn’t caused by any fungi or bacteria, it can dramatically reduce fruit quality and quantity.

In severe cases, calcium deficiency can also cause weak stems and leaves. It may be the reason why your tomato plant leaves are turning brown and curling upwards. However, the most reliable way to confirm a lack of calcium in the soil is through a soil test, done by a university or extension offices.

Simply take samples from several locations within the planting area and mix them in a container, then submit it for testing. Home test kits are also available at most gardening stores. However, they may not be as accurate as professional soil testing services. If you decide to use them, then follow the instructions properly.

Homemade calcium for tomato plants

There are several homemade options for boosting calcium for your tomato plants. They include the following:


Using eggshells is a very cost-effective way to add calcium to your soil. Eggshells are made almost entirely of calcium carbonate crystals glued by proteins. They also contain potassium, magnesium, zinc, iron, and phosphorus in small percentages.

There are several ways to use eggshells for tomato plants. You can simply crush and add them directly to the soil or make eggshell tea.

  1. Save your eggshells after use and rinse them clean to remove any egg residue.
  2. Dry them completely in the sun or in a well-ventilated area. Alternatively, place them in a 300-degree F heated oven. 
  3. Once the eggshells are dry, crush them into a fine powder using a mortar and pestle.
  4. Mix the crushed eggshells directly into the soil around your tomato plants. You can also add them to the planting hole when setting out new transplants.

It’s important to note that eggshells are a slow-release source of calcium. It can take weeks for the calcium to become available to the plants.  So, be patient if your plants are still showing signs of deficiency. For faster results, consider creating a calcium-rich solution to use as a foliar spray. 

Boil a handful of eggshells in a gallon of water for about 10 minutes. Remove the eggshells and let the water cool completely. Dilute the cooled eggshell tea with an equal amount of water and apply directly to your plants.  You may also consider using commercially available supplements like calcium nitrate.

Calcium nitrate is a water-soluble calcium source that can be applied as a soil drench or foliar spray. It’s a readily available form of calcium that can help correct a calcium deficiency quickly. Be sure to use as directed on the product label by the manufacturer.

Note: Too much calcium in the soil can affect a plant’s uptake of other nutrients. The outcome includes orange or reddish spots on the leaves, stunted growth, and leaf drop. This shows magnesium, iron, and potassium deficiency.

Tums Tablet

Surprisingly, crushed Tums tablets can be used as a source of calcium for plants. Since they are rich in calcium carbonate plus flavors and colorings, using them isn’t won’t harm your plants but provide the much-needed calcium. Dissolve 4-6 Tums tablets in a gallon of water and apply as foliar spray.

Wood Ash

Wood ash can be a good source of calcium carbonate. However, it can raise the pH of your soil. Tomatoes prefer slightly acidic soil (around 6.0 to 6.8 pH). If your soil is already alkaline, adding wood ash can make it too high for tomatoes. Moreso, salts in wood ash can burn the roots of your tomato plants.

Before using wood ash on your tomatoes, test the pH of your soil. You can purchase a soil test kit from most garden centers. Alternatively, send a sample of your soil to a professional soil testing lab. If your soil pH is already above 6.8, it’s best to avoid using wood ash.

Composting wood ash for a few months can help reduce its salt content. Simply add it to your compost pile and mix it occasionally. When ready, Spread it around the base of the plant, keeping it a few inches away from the stem. The best time to apply wood ash would be early enough before planting.

Final thought

Calcium acts as a foundational element for healthy tomato plants. It strengthens their structure, aids in nutrient management, and prevents disorders like blossom end rot, ultimately leading to better-quality fruits. In addition to deficiency symptoms, a soil test can tell if calcium levels are in decline and whether moreis needed.

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