How to Add Calcium to Plants Using Epsom Salt

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Things You'll Need

  • Tablespoon

  • Scale

  • Water

  • Spray bottle


Do not use Epsom salts on sage, which doesn't benefit from Epsom salts. They have a negative effect on this herb.

Fertilize your plants for a greener, more beautiful garden.

Epsom salts have many benefits for the body since they help draw toxins, sedate the nervous system and soothe and soften feet. Besides being beneficial for your health and beauty, Epsom salts are also beneficial in your garden. Epsom salts, or magnesium sulfate, help make plants bushier, help produce more flowers, increase the production of chlorophyll and help seeds to germinate. Used as a fertilizer, Epsom salts help absorb phosphorous and nitrogen. Epsom salt is also a source of calcium, and will help restore the calcium in your plants and soil.


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Step 1

Determine whether lack of calcium is exactly what is affecting your plants. A lack of calcium causes plants to rot; in plants such as tomatoes, this is known as blossom end rot. When there isn't enough calcium in the soil, the tomatoes rot before they become ripe.

Step 2

Add Epsom salts to restore the calcium in the soil for your plants. The amount you use depends on the type of plants you are growing. Epsom salts, a source of calcium and magnesium, will help plants grow. Refer to instructions from Epsom Salt Industry Council, available online, to determine the amount of Epsom salts to use.


Step 3

Measure the amount of Epsom salts your plants need using a tablespoon or scale, depending on the specific instructions. Note the date so you know when to add Epsom salts again.

For peppers, mix 1 tbsp. of Epsom salts with a gallon of water. Add to the soil when the plants bloom, and repeat 10 days later.

For tomatoes, add 1 tbsp. for each foot of plant height per plant every two weeks, as recommended by Epsom Salt Industry Council. To prevent blossom end rot, Twin Oaks Nursery recommends using 1 lb. of Epsom salt per bed garden, or 1 cup per tomato container. Also, spray a mixture of 1/2 cup of Epsom salts per gallon of water onto the tomato plants while they are growing, instead of regular watering, from time to time.


In the garden, use Epsom salts every two to four weeks, 1 tbsp. for every 9 feet of shrubs such as evergreens, azaleas and rhododendron. For lawns, use 3 lbs. of the salt mixed with water in a sprayer for every 1,250 square feet. Before you plant your plants, apply 1 cup of Epsom salts for every 100 square feet in your garden. For trees, use the salts three times a year, in the amount of 2 tbsp. for every 9 square feet.

To fertilize houseplants, each month, mix 2 tbsp. with a gallon of water. For roses, both inside and outside the house, use Epsom salts once every two weeks. Use 1 tbsp. of Epsom salts per foot of plant. Spray the roses weekly with an Epsom salts mixture of 1 tbsp. of salt per gallon of water. This will help get rid of any pests.


Step 4

Mix 1 tbsp. of Epsom salts with a gallon of water and pour into a sprayer. Spray this mixture onto any blooming plants such as tomatoes, peppers and roses. You can also sprinkle the salts over the soil of your plants. When using the salt in a dry form, however, make sure it doesn't touch the plant itself.

Step 5

Repeat the process of adding Epsom salts on a regular basis. Your plants should improve after just one use of the salts.


references & resources

Aleksandra Ozimek

Aleksandra Ozimek has been writing professionally since 2007 for a fashion blog, various online media and the "Queens Courier," in addition to interning at "Cosmopolitan" magazine. She completed her Bachelor of Science in journalism and photography from St. John's University, where she is completing her master's degree.