Learn which plants thrive in your Hardiness Zone with our new interactive map!

How to Make Food for Plants With Epsom Salts

By Meg Butler ; Updated September 21, 2017
Epsom salt is good for certain plants.

Epsom salt gets its name from Epsom, England, where Epsom salt was most distilled from local spring water. Epsom salt has a variety of practical uses. Because it is a rich source of magnesium sulfate, Epsom salt is often used as plant food in areas with low magnesium levels for plants with high magnesium needs. This natural plant food is easy to make and apply.

Step 1

Add Epsom salt to a large container that holds more than gallon of liquid. Use 1 tablespoon to feed peppers, shrubs per 9 square feet of soil underneath the shrub's canopy and tomatoes per foot of height. Use 2 tablespoons to feed trees per 9 square feet of soil underneath the tree's canopy.

Step 2

Pour 1 quart of boiling hot water over the Epsom salts.

Step 3

Stir the water well until the Epsom salt completely dissolves.

Step 4

Pour 3 quarts of ice-cold water into the mixture and stir well. The water should be about room temperature.

Step 5

Apply the room-temperature mixture to your plants. Give pepper plants a foliar spray. Pour the mixture into a spray bottle and coat the leaves of pepper plants with the spray once the plant is in full bloom. Repeat the spray again in 10 days. Water tomato plants and shrubs with enough mixture moistening the top 8 inches of soil. Repeat the watering once every two weeks for tomatoes, although shrubs can wait four weeks in between watering. Water trees with Epsom salt mixture. Water the entire area under the canopy. Repeat this procedure three times a year.


Things You Will Need

  • Epsom salt
  • Large container
  • Measureing spoons
  • Water
  • Spray bottle


  • Only evergreen, azalea and rhododendron shrubs need Epsom salt food.
  • For trees with very large root zones, add another gallon or so of water to the mixture for even spreading. Be sure to stir the mixture well.
  • Store unused Epsom salt plant food in a cool, dark spot.
  • According to Linda Chalker-Scott, Ph.D., Washington State University Extension Urban Horticulturist, Epsom salt plant foods are not always necessary. They should only be applied to the certain plants when growing on soil proved by a soil test to be magnesium deficient. Use on plants with low-magnesium needs or plants grown on healthy soil may harm the plants.


  • Never apply Epsom salt to sage plants.
  • Do not use Epsom salts on potted plants. The eventual salt build-up may eventually harm the plant.

About the Author


Based in Houston, Texas, Meg Butler is a professional farmer, house flipper and landscaper. When not busy learning about homes and appliances she's sharing that knowledge. Butler began blogging, editing and writing in 2000. Her work has appered in the "Houston Press" and several other publications. She has an A.A. in journalism and a B.A. in history from New York University.