Successfully growing tomatoes one year is enough to convince any gardener that it will be just as easy to do again. However, tomatoes are very susceptible to a range of formidable pests, including aphids, leafminers, mealybugs, caterpillars, plant bugs, and spider mites. Plant diseases like blight and leaf spot are also common concerns for gardeners, but one thing that is often overlooked is deficiency.
Even the most enthusiastic growers can find themselves puzzled when once-thriving tomato plants start to look a little off. Yellowing leaves, patchy fruit, and poor growth can set in, and despite your best efforts, they just don’t perk up. Gardening experts suggest that the solution might be sitting in your bathroom cabinet.
While it’s common to reach for a tomato feed high in potassium during the flowering and fruiting phase, magnesium is often overlooked.
According to the Royal Horticultural Society, magnesium is a key player in chlorophyll production. Without it, photosynthesis slows down, and growth suffers.
Andrew Koehn, horticulturist at Scribner’s Catskill Lodge in Hunter, New York, notes that Epsom salts are a worthwhile solution if magnesium is definitely the problem, but they should be used with caution.
He told Martha Stewart: “Magnesium deficiency usually appears as leaves with bright green ribs and veins and otherwise discoloured areas of yellow, red, or brown.”
The horticulturalist 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.”
Plant growth may be stunted with fewer tomatoes to pick if magnesium deficiency is untreated.
To confirm a magnesium deficiency, a quick soil test with a home test kit should suffice. Otherwise, the clearest signs on the plant include yellowing between the veins of older leaves, sometimes with reddish-brown tints
Older leaves may also develop brown patches and eventually drop off prematurely. Fortunately, you can remedy the problem right away by feeding tomatoes Epsom salts once a month throughout the growing season.
Epsom salt, also known as magnesium sulfate, is a naturally occurring mineral compound of magnesium, sulfur, and oxygen.
Dissolve one tablespoon of Epsom salts in a gallon (just under four litres) of water and apply to the base of the plant.
Alternatively, you can dissolve one tablespoon of Epsom salts into a gallon of water and spray it on the leaves for fast absorption.
It’s important to remember that magnesium deficiency may not always mean a true lack of magnesium in the soil. High levels of potassium from fertilisers can interfere with magnesium uptake, so balance matters.
Epsom salt is best used as a supplement, not a cure-all, so it should be used sparingly. Monitor plants after application and stop if you don’t see an improvement.
Andrew said: “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.”