Epsom salt used as a foliar spray or soil additive will help tomato and pepper plants grow and produce larger, tastier yields.
Late in the season use an Epsom salt spray to increase tomato and pepper yield and keep plants green and bushy; early in the season add Epsom salt to the soil to aid germination, early root and cell development, photosynthesis, plant growth, and to prevent blossom-end rot.
Epsom salt is not actually salt but a natural mineral compound of about 10 percent magnesium and about 13 percent sulfur—often referred to as magnesium-sulfate. Epsom salt is highly soluble and easily taken in by plants when combined with water and sprayed on leaves. As a soil additive, Epsom salt becomes soluble with soil moisture and is drawn up into plants through the roots.
A magnesium or sulfur deficiency in the soil can cause tomato and pepper plants to grow small and spindly, leaves to yellow between leaf veins late in the season, and fruit to be slow in maturing and ripening.