Epsom Salts

Asked February 7, 2018, 12:37 AM EST

I am hearing conflicting opinions about using epsom salts in the garden. Is it safe? Is it good for certain types of plants? Does it build up in the soil and become toxic?

Benton County Oregon

1 Response

Epsom Salts is not a substance that is recommended by Oregon State University. There are many home gardening practices that have no scientific basis and continue to be used by gardeners, Epsom Salts is one.

The conflict that you hear comes from the difference in findings of researchers versus the ‘experience” of the gardeners. The message from researchers to home gardeners is there is no scientific proof that Epsom Salts has any beneficial effect on plants. The gardeners who use Epsom Salts say, “look at my beautiful Roses, big tomatoes & peppers, I have used it for years!”.

Epsom salts contains hydrated magnesium sulfate. Plants use trace amounts of both Sulphur and magnesium. Both of these minerals are found naturally in the soil. Home gardener’s plants use trace amounts of these minerals that are naturally found in soil. To be sure you do not have a deficiency of these minerals in your soil have a soil test performed.

The main plants that home gardeners use Epsom Salts are roses, tomatoes, and peppers.

Here is a link to a very good paper on Epsom Salts and their use.


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