Epsom Salt for Plants: Real Benefits, Myths, and Safe Dosages
When you hear Epsom salt, a naturally occurring mineral compound of magnesium and sulfur. Also known as magnesium sulfate, it's been used for decades in gardens to fix yellowing leaves and boost fruiting. But here’s the truth: it doesn’t fix everything. If your soil already has enough magnesium, adding Epsom salt won’t make your plants grow faster or greener—it just wastes money and could even harm them.
Most gardeners use it because they heard it helps tomatoes or roses. And yes, those plants can benefit—if they’re suffering from a real magnesium deficiency, a condition where leaves turn yellow between the veins while the veins stay green. But that’s rare in UK soils. More often, yellow leaves come from overwatering, poor drainage, or lack of nitrogen. Before you sprinkle anything, do a simple soil test, a low-cost way to check nutrient levels before adding amendments. You can buy one online for under £15. It’ll tell you if you even need magnesium, or if you’re just guessing.
There’s no magic formula for how much to use. Too little won’t help. Too much can lock out other nutrients like calcium. For tomatoes, a common recommendation is one tablespoon per plant, dissolved in water and applied every two weeks during flowering. But if your soil is already rich, that’s pointless. Same goes for roses—some gardeners swear by it, others see no change. The key is matching the treatment to the actual problem. And if your plants are struggling, look at the bigger picture: are they getting enough sun? Is the soil draining well? Are you watering too much? Epsom salt isn’t a cure-all. It’s a targeted fix for one specific nutrient gap.
What you’ll find in the posts below are real, no-fluff guides on how to use Epsom salt safely, when to avoid it, and what to do instead. You’ll also get clear advice on other soil fixes—like using compost to improve structure, or how vinegar and coffee grounds interact with your plants. No myths. No hype. Just what works, based on what gardeners in the UK have actually tried.