Epsom Salts for the Garden. Are the leaves on your tomatoes or pepper plants turning yellow? Want more blooms on your rose bushes? Wondering why your lawn is looking brown? Boost plants and grass with Epsom salt, high in magnesium and sulfur. Helps plants grow greener with higher yields and more blooms. 1 handful to 1 square meter. OR 3 table spoons to 1 liter water