Myth: Epsom Salts are a good fertilizer and will promote blooms, make tomatoes and peppers more productive and are a general “cure-all” for the garden.
Fact: Epsom salts contain magnesium sulfate (MgSO4), a very simple chemical consisting of magnesium, water and sulfur. Magnesium is one of the minor elements which plants need to grow, and it is rarely deficient in soils in Central Texas. It may be deficient in a sandy, acidic soil, but we don’t have to worry about that here! A soil test will confirm if the soil is deficient in magnesium.
Adding too much magnesium to the soil can actually tie up calcium and make it unavailable to the plant. Since tomato plants need calcium to prevent blossom end rot, adding Epsom salts to the soil may make blossom end rot worse!
Epsom salts contain no nitrogen, no phosphorus, and no potassium. In fact, its analysis is 0-0-0! It does not contain ANY of the major nutrients required for plant growth.
Spraying Epsom salts on plant foliage can cause leaf scorch, so DON’T DO IT!