Gardeners are being encouraged to use Epsom salts, a common bathroom item, to address magnesium deficiency in tomato plants, leading to juicier and bigger fruit yields throughout the season, according to horticulture experts.
Magnesium Deficiency in Tomatoes
Tomatoes are vulnerable to pests such as aphids, leafminers, mealybugs, caterpillars, plant bugs, and spider mites, as well as diseases like blight and leaf spot. However, nutrient deficiency—particularly magnesium—is often overlooked. Symptoms include yellowing leaves, patchy fruit, and stunted growth, which can persist despite other care efforts.
The Royal Horticultural Society states that magnesium is essential for chlorophyll production. Without sufficient magnesium, photosynthesis slows and plant growth declines.
Epsom Salts as a Solution
Andrew Koehn, a horticulturist at Scribner's Catskill Lodge in Hunter, New York, told Martha Stewart that Epsom salts (magnesium sulfate) are effective if magnesium deficiency is confirmed. He noted: "Magnesium deficiency usually appears as leaves with bright green ribs and veins and otherwise discoloured areas of yellow, red, or brown." He added: "Magnesium is the center of the chlorophyll molecule, so it's crucial for good green colour in leaves and therefore good for overall plant health."
Untreated magnesium deficiency can stunt plant development and reduce harvests. A simple soil test using a home testing kit can confirm the deficiency. Visual signs include yellowing between veins of older leaves, reddish-brown hues, brown patches, and premature leaf drop.
How to Apply Epsom Salts
To treat the issue, dissolve one tablespoon of Epsom salts in a gallon (just under four litres) of water and apply to the plant's base once monthly throughout the growing season. Alternatively, spray the solution onto leaves for rapid absorption. However, excessive potassium from fertilisers can impede magnesium uptake, so balance is crucial.
Koehn cautioned: "Applying Epsom salt or additional magnesium when your plants don't need it may stunt plant growth and turn them too green, which is not good for plant health overall." Use Epsom salts sparingly as a supplement, and discontinue if no improvement is observed.
