bunch of Capsicum anuum red peppers
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Will Your Pepper Plants Benefit From A Sprinkle Of Epsom Salt?
According to the University of Minnesota, there's no scientific evidence that treating your peppers (Capsicum annuum) with Epsom salt improves productivity, growth, or fruiting.
Epsom salt contains 10% magnesium, so it's only needed if your dirt is deficient. This rarely happens, as most U.S. soils are naturally magnesium-rich.
If your garden soil is very acidic, leeches often due to rain or overirrigation, or is clayey, it might be magnesium-deficient, so it's crucial to get it tested before adding Epsom salt.
If peppers show signs of interveinal chlorosis, like yellowing leaves, defoliation, and reduced fruiting, the soil may need magnesium, or it could be out of balance.
For example, high levels of potassium in soil can prevent pepper plants from absorbing magnesium, so adding Epsom salt is pointless as the plants are unable to take it up.
Instead, depending on the results of a soil test, you’d need to add nitrogen or reduce potassium. If the tests reveal low magnesium levels, Epsom salt may help your pepper plants.
However, water-soluble Epsom salt may flow right out if added to leached soil, so most professionals recommend adding dolomite limestone, kieserite, or biochar instead.
Horticulturist Charlie Nardozzi published a study on the National Gardening Association's website claiming Epsom salt helps pepper plants grow better and produce better fruit.
Professor of horticulture Debbie Flower, who was quoted in 2018's The Yolo Gardener, says plants can't absorb diluted Epsom salt; instead, it causes leaf scalds and soil build-ups.
Dr. Linda Chalker-Scott in 2018 quoted studies that found concentrated levels of Epsom salt caused salt injuries and boron and calcium deficiencies in plants, which can rot them.
A Pennsylvania Delaware Valley College study found no positive effects of adding Epsom salt. Other studies found it unlocks the soil's aluminum and harms nitrogen-fixing microbes.