Is Epsom Salt Good for Tomato Plants?

Did you know that tomatoes are America’s favorite plant for the home garden? It’s not hard to see why. They don’t take up a lot of growing space, continually produce fruit, and are easy to grow. Tomatoes are also an excellent source of lycopene, which has been shown to lower the risk of many types of cancer.

Plus, they have practically unlimited culinary uses. Their versatility is terrific for the home cook because tomatoes taste good, too. And no store-bought version can top the taste of a homegrown tomato.

If you are an avid gardener, I don’t have to tell you that there are a lot of different growing techniques out there. It seems like everyone has their tricks to growing the best-tasting tomatoes. One of the most commonly recited gardening tips is to use Epsom salts as a fertilizer.

This tip makes sense. After all, there are some scientific reasons for using Epsom salt in the garden. Epsom salt is not a salt but rather a natural mineral compound. It’s often referred to as magnesium-sulfate because it’s about ten percent magnesium and thirteen percent sulfur. Magnesium and sulfur are vital micronutrients for healthy plant functions like photosynthesis.

Under certain conditions, applying Epsom salt to tomato plants could make them healthier, but not always. In some situations, it could make tomato plants sick or contaminate the ground. Unabsorbed, Epsom salts can wash into the groundwater, streams, or even lakes.

Let’s examine three of the most common questions about using Epsom salt when growing tomatoes.

Does Epsom Salt Prevent or Treat Tomato Blossom End Rot?

Tomato Blossom End Rot - Care2

(Photo: Greyvillea)

No. Sorry, this is a wide-spread gardening myth. Unfortunately, Epsom salt can’t do that.

Blossom end rot is a physiological disorder that affects tomatoes and peppers. It isn’t related to a magnesium deficiency though — the most common causes are fluctuating moisture levels or a lack of calcium — so adding Epsom salts won’t help prevent it (or treat it) since they contain no calcium at all.

In fact, according to North Dakota State University, adding Epsom salts can lead to more blossom end rot in certain circumstances. Magnesium competes with calcium uptake in tomato plants; the more there is, the less chance that calcium will be absorbed.

Myth busted.

Can Epsom Salt Treat Yellowing Leaves on Tomato Plants?

Tomato Garden - Care2

(Photo: Thinkstock)

Maybe.

There are many possible causes for yellowing leaves on tomato plants like insect damage, fungal diseases, or a deficiency in nutrients. Since Epsom salt contains magnesium, if the yellowing leaves are due to a lack of magnesium, then Epsom salts might help green them up. But it’s important to do your homework before automatically adding Epsom salt to your plants.

Linda Chalker-Scott, Ph.D., Master Gardner at the Puyallup Research and Extension Center at Washington State University, advises gardeners to determine not only the needs of the plant but the soil and the environment too before deciding to use fertilizers like Epsom salt in the garden.

According to her, it’s all about the science. “The science behind the use of Epsom salts is only applicable to intensive crop production in situations where magnesium is known to be deficient in the soil or in the plants.”

She says adding Epsom salts to soils that are not magnesium deficient can injure the plant or even contaminate the soil.

The only way to determine if your soil is magnesium deficient is through a soil test. When in doubt, test the soil.

Will Epsom Salt Create Sweeter Tasting Tomatoes?

Homegrown tomatoes - Care2

(Photo: Thinkstock)

The answer depends on who you ask. Some gardeners swear that adding Epsom salt around tomato plants will sweeten the fruit. Others argue that Epsom salt will only have a positive effect on flavor if the soil is already deficient in micronutrients.

Who’s right?

Well, Epsom salt does contain the micronutrients magnesium and sulfur. And having the proper micronutrient supply in the soil is an essential factor of growing tomatoes. So, some gardeners could find that using Epsom salts creates a better tasting tomato. But this is only true when the soil is deficient in the first place.

Care2 Gardeners, let’s talk tomatoes! What varieties work well for you? Do you have a full garden at your house or are you like me and have a container garden? Tell me about your tomato tips, tricks, and growing stories in the comments!

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Photos: Thinkstock & Flickr

57 comments

hELEN hEARFIELD
hELEN hEARFIELD2 months ago

tyfs

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Ruth S
Ruth S2 months ago

Thanks.

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Renata B
Renata B3 months ago

Thank you!!! I didn't know anything of this.

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Danuta W
Danuta W3 months ago

thanks for posting

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Olivia M
Olivia M3 months ago

tyfs

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John W
John W4 months ago

Thanks.

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Julie W
Julie W4 months ago

Colin C, a pH test will tell you if your soil is acid, alkaline or neutral, not what nutrients it contains..

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Pearl W
Pearl W4 months ago

Hi All - Don't ya just love a foot soak in Epsom Salts - I do - No way would I waste the water - I put about a quarter of it in the watering can, add more water and put it on the garden or lawn - Good for flowers too - Thanks - smiles

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Marija M
Marija M4 months ago

tks againn

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Shirley Plowman
Shirley Plowman4 months ago

tOMATOES GROWING THIS YR IN MY GDN, HOPING FOR A LUSH, HEALTHY CROP, LOVE THEM.

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