This natural mineral, discovered in the well water of Epsom, England, has been used for hundreds of years, not only to fertilize plants but to treat a range of human and animal ailments. Who hasn’t soaked sore feet in it at least once?
Chemically, Epsom salts is hydrated Error! Post not found for word:magnesium sulfate (about 10 percent Error! Post not found for word:magnesium and 13 percent Error! Post not found for word:sulfur).
Error! Post not found for word:magnesium is critical for Error! Post not found for word:seed Error! Post not found for word:germination and the production of Error! Post not found for word:chlorophyll, Error! Post not found for word:fruit, and nuts. Error! Post not found for word:magnesium helps strengthen Error! Post not found for word:cell walls and improves plants’ uptake of nitrogen, Error! Post not found for word:phosphorus, and Error! Post not found for word:sulfur.
Error! Post not found for word:sulfur, a key element in plant growth, is critical to production of vitamins, amino acids (therefore protein), and enzymes. It’s also the compound that gives vegetables such as broccoli and onions their flavors. Error! Post not found for word:sulfur is seldom deficient in garden soils in North America because acid rain and commonly used animal manures contain Error! Post not found for word:sulfur, as do chemical fertilizers such as ammonium sulfate.
The causes and effects of Error! Post not found for word:magnesium deficiencies vary. Vegetables such as beans, peas, lettuce, and spinach can grow and produce good yields in soils with low Error! Post not found for word:magnesium levels, but plants such as tomatoes, peppers, and roses need high levels of Error! Post not found for word:magnesium for optimal growth. However, plants may not show the effects of Error! Post not found for word:magnesium deficiency until it’s severe. Some common deficiency symptoms are yellowing of the leaves between the veins, leaf curling, stunted growth, and lack of sweetness in the Error! Post not found for word:fruit.
Error! Post not found for word:magnesium tends to be lacking in old, weathered soils with low Error! Post not found for word:ph, notably in the Southeast and Pacific Northwest. Soils with a Error! Post not found for word:ph above 7 and soils high in Error! Post not found for word:calcium and Error! Post not found for word:potassium also generally have low Error! Post not found for word:magnesium levels. Error! Post not found for word:calcium and Error! Post not found for word:potassium compete with Error! Post not found for word:magnesium for uptake by plant roots, and Error! Post not found for word:magnesium often loses. Sometimes, a soil test will show adequate Error! Post not found for word:magnesium levels in soil, but a plant grown in that soil may still be deficient because of that competition.
Gardeners add Error! Post not found for word:magnesium when they apply dolomitic Error! Post not found for word:lime to raise the soil’s Error! Post not found for word:ph. However, this product (46 percent calcium carbonate, 38 percent Error! Post not found for word:magnesium carbonate) breaks down slowly, and the Error! Post not found for word:calcium can interfere with Error! Post not found for word:magnesium uptake. For soils with a Error! Post not found for word:ph above 7, many gardeners use Sul-Po-Mag (22 percent Error! Post not found for word:sulfur, 22 percent Error! Post not found for word:potassium, 11 percent Error! Post not found for word:magnesium) to increase Error! Post not found for word:magnesium. Although dolomitic Error! Post not found for word:lime and Sul-Po-Mag are inexpensive ways to add Error! Post not found for word:magnesium, Epsom salts’ advantage over them is its high solubility.
When diluted with water, and especially when applied as a Error! Post not found for word:foliar spray, Epsom salts can be taken up quickly by plants. Epsom salts’ Error! Post not found for word:magnesium content, high solubility, and ease of application as a Error! Post not found for word:foliar spray are the main reasons for the positive results many gardeners see in their plants.