Gardening with Epsom salt

Grow bigger, better plants with Epsom salt. Experts recommend gardeners use Epsom salt to prepare soil for planting and to treat and feed specific plants, including peppers, tomatoes, fruit and roses. Epsom salt can also help keep house plants, lawns, trees and shrubs healthy.

Why is Epsom salt good for plants?

Studies show that magnesium and sulfur, two naturally occurring minerals that are major components of Epsom salt, may help plants grow greener with higher yields and more blooms. Magnesium creates an environment conducive to growth by helping seeds germinate, increasing chlorophyll production and improving phosphorus and nitrogen uptake. Sulfur is also a key element in plant growth, helping produce vitamins.

Tests by the National Gardening Association show that Epsom salt helps produce more flowers and makes pepper plants grow larger. In addition, experts say Epsom salt reduces the total amount of fertilizer your plants need—and makes the fertilizer you do use more effective.

How do you know if your plants need Epsom salt?

Before you plant, test your soil by sending a sample to county extension agents. We recommend doing this every one to three years. Your agent can also help diagnose problems with plants. Here’s how to find your nearest extension office.

Prepare your soil before you plant.

  1. Sprinkle 1 cup of Epsom salt over every 100 square feet of soil.
  2. Mix into the soil before planting.

Note: Sage and Epsom salt don’t mix! Sage is one of the few plants that doesn’t benefit from an Epsom salt boost, so avoid adding it to the soil where you grow the herb.

Feed and treat your plants with Epsom salt.

Fertilizer can cause salt buildup in soil, which can interfere with plant growth. Epsom salt helps separate fertilizer bound to the soil, making the nutrients more available to your plants. Some growers swear that the use of Epsom salt as a secondary nutrient makes their fruit sweeter.

Here’s how to use Epsom salt to encourage better growth in a variety of specific plants:

Fruit

  1. For every 500 square feet of soil, mix ¼ cup Epsom salt with water.
  2. Apply the mixture when you irrigate your fruit plants.

Houseplants

  1. Dilute 2 tablespoons of Epsom salt in 1 gallon of water.
  2. Use mixture to feed houseplants monthly.

Lawns

  1. Apply 3 pounds of Epsom salt for every 1,250 square feet of lawn.
  2. Apply with a spreader or dilute the Epsom salt in water and use a sprayer.

Peppers

  1. Dilute 1 tablespoon of Epsom salt in 1 gallon of water.
  2. Spray your peppers at bloom time.
  3. Ten days later, spray again.

Roses

  1. At planting time: Add 1 tablespoon Epsom salt to each hole.
  2. To help roots recover: Dilute ½ cup Epsom salt in 1 gallon of water and soak unplanted rose bushes in mixture.
  3. To encourage flowering canes and healthy new basal cane growth: Scratch ½ cup Epsom salt into the soil at the plant base.
  4. To discourage pests: Dilute 1 tablespoon Epsom salt in 1 gallon of water per foot of plant height and spray roses with solution weekly.
  5. “Wake up” your roses with this Epsom salt tip from master gardener Linda Cobb.

Shrubs (evergreens, azaleas and rhododendron)

  1. Dilute 1 tablespoon Epsom salt in water for every 9 square feet.
  2. Apply to the root zone every 2 to 4 weeks.

Tomatoes

  1. Dilute 1 tablespoon Epsom salt in water for every foot of plant height per plant.
  2. Apply every 2 weeks.

Trees

  1. Dilute 2 tablespoons of Epsom salt in water for every 9 square feet.
  2. Apply to the root zone 3 times each year.

Learn more about how Epsom salt works in your garden below.