Gardening experts have identified a common bathroom cabinet staple that may help fix magnesium deficiency in tomato plants, potentially leading to bigger and juicier fruit. Epsom salt, or magnesium sulphate, is a natural mineral that can be applied monthly during the growing season to boost plant health.
Magnesium Deficiency in Tomatoes
Tomatoes are highly susceptible to pests like aphids, leafminers, mealybugs, caterpillars, plant bugs, and spider mites, as well as diseases such as blight and leaf spot. However, nutrient deficiency, particularly magnesium, often goes unnoticed. Symptoms include yellowing leaves, fruit patches, stunted growth, and overall decline. According to the Royal Horticultural Society, magnesium is essential for chlorophyll production; low levels slow photosynthesis and harm plant health.
Andrew Koehn, horticulturist at Scribner's Catskill Lodge in Hunter, New York, explained to Martha Stewart: "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."
Identifying and Treating Magnesium Deficiency
A simple soil test with a home kit can confirm magnesium deficiency. Visual signs include yellowing between leaf veins on older foliage, sometimes with reddish-brown tinges, and brown spots that cause premature leaf drop. To treat, mix one tablespoon of Epsom salts into a gallon (just under four litres) of water and pour around the plant's base. Alternatively, dissolve the same amount in water and spray directly onto foliage for quicker uptake. Apply monthly during the growing period.
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." High potassium levels from fertilisers can block magnesium uptake, so balance is crucial. Epsom salt works best as a supplement, not a miracle solution. Monitor plants after application and discontinue if no improvement is seen.
