You should skip plants not use Epsom salts on like beans, peas, beets, radish, lettuce, Swiss chard, and sweet potatoes. These crops grow fine in soil with low magnesium. Alabama Extension lists all of them as tolerant, which means they pull enough from your regular garden soil on their own.
Treating these crops can epsom salt harm plants by adding salt where your soil does not need it. I spent a full season giving my lettuce and bean rows monthly Epsom salt drenches. Nothing changed. The treated rows looked the same as the ones I left alone. My lettuce heads weighed the same, the beans set at the same rate, and the leaf color matched. I wasted product and added salts to beds that did not need them. Your results will be the same if you try it.
These plants handle low magnesium well because of how they grow. Your beans and peas have roots that pull nutrients from soil even when levels are low. Lettuce and Swiss chard make leaves without setting heavy fruit. They never drain magnesium the way your tomatoes or peppers do. Beets, radish, and sweet potatoes store energy in their roots and just do not need much magnesium to do it.
When you add Epsom salt to soil that already has enough magnesium, the extra salts sit in the root zone. They start blocking water from reaching your roots. Your plants can wilt even when the soil feels damp to your touch. This salt stress looks like drought stress. It tricks you into watering more, which makes everything worse by pushing salts deeper around the roots.
Too much magnesium also fights with calcium and potassium at the root level. If you push magnesium too high, your plants may show calcium shortage signs like blossom end rot or weak stems. The roots can only take in so many nutrients at once. Too much of one blocks the others from getting through to your plant.
The best approach for your mixed garden is targeted treatment. Only treat plants that show clear signs like yellow patches between leaf veins on older leaves. If your beans, peas, lettuce, or beets look healthy and green, leave them alone. These are plants that don't need magnesium added to their soil, and treating them just wastes your time while causing problems.
Get a soil test before you add Epsom salt to any part of your garden. A $15 lab test shows you what your soil needs and what it already has. Only apply to confirmed low areas and only to crops that respond well to extra magnesium. Skip your tolerant crops and save your effort for the plants that will show you a real difference in growth.
Read the full article: Epsom Salt for Plants
