How to Use Epsom Salt for Plants
You can buy Epsom salt in the drugstore, but learning how to use Epsom salt for plants can help them thrive when applied correctly.
Epsom Salt vs. Other Types of Salt
While table salt and rock salt are harmful to plants, Epsom salt has been found to be beneficial under the right conditions. Table salt and road salt can kill plants, while salty ocean spray causes damage to coastal vegetation. However, Epsom salt is believed to provide benefits for plant health.
What Epsom Salt Is
Epsom salt, also called magnesium sulfate, is made of magnesium, sulfur, and oxygen. Though it resembles table salt, it differs in taste and function. As a naturally occurring micronutrient in soil, magnesium from Epsom salt helps plants absorb nutrients more effectively.
Humans use Epsom salt for various reasons, such as in baths to relieve muscle soreness. It is also consumed as a remedy for certain ailments, but medical advice should be sought before internal use. Pregnant women or those with kidney issues and skin conditions are advised to avoid it.
The Use of Epsom Salt for Plants
Many gardeners report that Epsom salt improves plant health, leading to bushier growth, vibrant color, and increased flower production. Some also believe it promotes seed germination and deters garden pests. However, the University of Minnesota Extension Service recommends its use only when a magnesium deficiency is confirmed in the soil, as excessive magnesium can be harmful.
Signs of Magnesium Deficiency in Plants
Testing soil through a local extension service is recommended before using Epsom salt. In potted plants, nutrient deficiencies may be indicated by yellowing leaves. A general yellow color suggests a sulfate deficiency, while leaves that yellow between green veins signal a magnesium shortage (interveinal chlorosis). Factors like soil pH and weather can also affect plant health, so expert advice should be obtained.
Plants That Should Avoid Epsom Salt
Certain plants should not be given Epsom salt due to their low magnesium needs, such as beans, leafy vegetables, and coniferous trees. Tropical palms, carnivorous plants like Venus flytraps, and insect-eating plants should also avoid it, as they thrive in nutrient-poor soils.
Using Epsom Salt on Specific Plants
While tomatoes, peppers, and roses may benefit from magnesium, soil tests are necessary before application. Claims that Epsom salt prevents blossom-end rot are debated, as some experts believe additional magnesium could worsen the condition.
Application Tips for Epsom Salt on Plants
Epsom salt should always be diluted in water before use. Plants should be drenched at the roots or sprayed on the leaves. Spraying during hot, sunny days should be avoided to prevent foliage burn.
Weed Control with Epsom Salt
Weeds can be killed with highly concentrated Epsom salt, often mixed with vinegar. However, caution must be taken as the solution can harm nearby plants through root absorption or spray mist.
How to Measure Epsom Salt for Plants
The following guidelines are recommended:
- General Use: 1 tablespoon of Epsom salt per gallon of water for monthly application.
- Foliar Spray: 2 tablespoons per gallon of water once a month.
- Houseplants: 2 tablespoons per gallon of water once a month.
- Shrubs: 1 tablespoon per 9 square feet every 2-4 weeks.
- Lawns: 3 pounds per 1,250 square feet, spread evenly or diluted with water.
- Trees: 2 tablespoons per 9 square feet, applied three times annually.
- Roses (Bare Root): Soaked in 1 cup of Epsom salt per gallon of water before planting.
- Roses (Established): 1 tablespoon per foot of height every two weeks.
In new gardens, Epsom salt can be sprinkled at a rate of 1 cup per 100 square feet and mixed into the soil before planting.
