Epsom salt helps in the creation of chlorophyll, which is vital for photosynthesis. In addition, magnesium greatly improves a plant’s ability to produce flowers and fruit. If the soil becomes depleted of magnesium, adding Epsom salt will help; and since it poses little danger of overuse like most commercial fertilizers, you can use it safely on nearly all your garden plants.

You should also be aware that many plants, like beans and leafy vegetables, will happily grow and produce in soils with low levels of magnesium. Plants like rose, tomatoes and peppers, on the other hand, require lots of magnesium, and therefore, are more commonly watered with Epsom salt.

When diluted with water, Epsom salt is easily taken up by plants, especially when applied as a foliar spray. Most plants can be misted with a solution of 2 tablespoons (30 mL) of Epsom salt per gallon of water once a month. For more frequent watering, every other week, cut this back to 1 tablespoon (15 mL).

With roses, you can apply a foliar spray of 1 tablespoon per gallon of water for each foot of the shrub’s height. Apply in spring as leaves appear and then again after flowering. For tomatoes and peppers, apply 1 tablespoon of Epsom salt granules around each transplant or spray (1 tbsp. or 30 mL per gallon) during transplanting and again following the first bloom and fruit set.