The Epsom Salt Garden Myth

There are times when garden advice is spot-on, and other times when a garden tip attains urban myth status. The Epsom salt garden tips fall somewhere in between. Epsom salt has long been touted as a preventative for blossom end rot, as a treatment for pest control, as an aid for encouraging rose blooms, and as a fertilizer — but are any of these claims true?

First, let’s take a look at what Epsom salt is, exactly. It’s a chemical that consists of magnesium and sulfur. It also contains water, but it’s a crystalline form, so the water content is not significant. Although plants do need magnesium to grow, they don’t need much of it, so magnesium by itself is not usually something that is necessary to add to your soil. Plants also need sulfur but, as with magnesium, they don’t need much in order to thrive.

So should we use it or not? Here are some good tips, facts, and recommendations for Epsom salt use in the garden — as always, it’s good to make garden decisions based upon solid knowledge and research rather than myth or well-intentioned neighborly advice.

1. Conduct a soil test before attempting to adjust a specific nutrient level in your soil. A thorough and complete soil test will tell you what nutrients your soil is lacking. Your local county extension office is a good resource for soil testing.
2. Use Epsom salt only if your soil test shows it is deficient in magnesium.
3. It’s relatively rare for soil to be deficient in magnesium or sulfur, particularly if you regularly add compost to your garden. That being said, sandy and acidic soils may have a higher incidence of magnesium deficiency.
4. Epsom salt has not been demonstrated through research to be an effective tool in managing pests and disease. In particular, Epsom salt may actually be a cause of blossom end rot rather than a preventative or a cure of it.
5. Epsom salt has not been demonstrated through research to help roses grow or bloom better.

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