Over the years Epsom salt has been recommended to treat so many ailments it is mind boggling. For generations this simple chemical composed of magnesium sulfur and oxygen has been used on humans, livestock and plants.
Some gardeners swear by it. Many folks who grow tomatoes, peppers and roses seem particularly enamored by it. Epsom salts are used for fertilizer, disease and pest control. Blossom end rot, a major tomato disease, is said to be controlled by Epsom salts as are slugs and snails.
Historically, this simple molecule of magnesium sulfate has been used by livestock farmers too. It is also used topically and internally to treat human ailments. I admit I use it sometimes, too. The question becomes, “how much is fact and how much is fiction?”
When it comes to plant nutrition, the answer is mixed. Magnesium and sulfur are both essential plant nutrients. However, they are not needed in the same quantities as the big three: nitrogen, phosphorus and potassium. Magnesium is an important component of the chlorophyll molecule, so it stands to reason plants would benefit from it.
The problem is that unless magnesium and sulfur are insufficient in the soil, there is no advantage to adding more. Nutrients should be in balance.
As far as blossom end rot of tomatoes goes, there is little hard evidence that Epsom salts help control it. Calcium deficiency is more important for blossom end rot development, and higher magnesium often leads to less calcium uptake. Magnesium salts do little for slug and snail control, unless individual mollusks are contacted.
If too much is added to the soil, the soil could be temporarily poisoned. When residue remains on the leaves, too much water could be drawn from them and they would scorch. It’s important to calculate application rates of anything.
My father-in-law frequently used Epsom salts when doctoring cattle and sheep. He used it internally to treat constipation and grass tetany. Grass tetany results from insufficient magnesium. These are both appropriate and effective uses. Taking Epsom salts internally will help bowels move in people, too.
He also used Epsom salts topically on wounds to keep them from getting infected and to reduce swelling. Again, these are proven uses. However, soaking in water alone can be effective too, as can soaking in salt water.
I soak puncture wounds and splinters in hot Epsom salts. A hot bath with this compound often is recommended to reduce muscle aches. Hot soaking with magnesium sulfate is also a traditional remedy for athlete’s foot and toenail fungus. Cold Epson salt preparations are sometimes used to treat poison ivy and insect bites.
Many medical researchers feel that much of the relief of symptoms is psychosomatic. Patients think it will work, so it does. Maybe that’s why there are claims for so many different ailments.
While there is no hard evidence soaking in Epsom salts helps alleviate problems, there is also no indication of side-effects either. Furthermore, magnesium sulfate is cheap. Sometimes we pay big money for drugs or supplements and they don’t help either.
Ted Manzer teaches agriculture at Northeastern High School.