5 Unbelievable Things Epsom Salt Does For Tomato Plants

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Growing tomatoes is often a labor of love, and many gardeners swear by their own tried and true methods for growing the best tomatoes. You may have heard you should plant your tomatoes with eggshells, banana peels, and/or Epsom salts.

Have you ever wondered why they recommend these things?

There’s a lot of good theory behind adding these things to your tomato at planting. Eggs shells contain calcium, banana peels release nitrogen and potassium, and Epsom salt contains magnesium which is vital for healthy plant growth.

But I hear a lot of misinformation about the role that Epsom salt serves in the garden, so in this post, I’m going to tell you the facts about what Epsom salt can do for tomato plants and which things are really just old wives’ tales.

Epsom salt is a natural mineral compound made up of magnesium and sulfate. It’s often recommended as a self-care product for sore muscles, cold symptoms, and medicated salves. Many gardeners also recommend applying Epsom salt to tomato plants for its amazing benefits to vigor, health, and flavor of the tomatoes.

But will it actually help? Or could Epsom salt actually be harming your tomato plants?

Let’s sort out fact from fiction. There is some scientific basis for the use of Epsom salt in the garden. That’s because magnesium and sulfur are very important for the growth and health of tomato plants.

These micronutrients are vital for photosynthesis, protein synthesis, and cell wall structure. So it makes complete sense that, under certain conditions, applying Epsom salt to tomato plants will make them healthier. But making blanket statements about the use of Epsom salt in the garden is misleading and could actually be harmful. So let’s take a look at some of the claims regarding Epsom salt and tomato plants.

Can Epsom salt prevent tomato blossom end rot?

No. Sorry, it doesn’t do that. Blossom end rot is a stress-induced disorder that affects tomato fruit. It is not usually related to a deficiency of nutrients in the soil, so adding Epsom salts won’t help prevent it.

However, magnesium will compete with calcium uptake in tomato plants. So if your soil is deficient in calcium or your pH is not optimum for calcium uptake, adding Epsom salt will actually make it more likely that you’ll have tomatoes with blossom end rot.

Related reading:

How To Fix And Prevent Blossom End Rot.

The Epsom Salt Myth: article by North Dakota State University

Try planting these disease resistant tomato varieties.

Blossom end rot is one of the most common tomato problems.
Blossom end rot on a green tomato.

Does Epsom salt make tomatoes taste sweeter?

Maybe. Epsom salt contains the micronutrients magnesium and sulfur. Growing flavorful tomatoes depends on many factors including a healthy micronutrient supply in the soil.

So by adding magnesium and sulfur to the soil, some gardeners may find that Epsom salt has a positive effect on flavor. But this is only your if their soil is already deficient in micronutrients. If the soil is deficient in micronutrients, then perhaps a more balanced fertilizer is a better option than using Epsom salt alone.

Should you be fertilizing your tomatoes with Epsom salts?

Probably not. As already discussed, Epsom salt does contain 2 micronutrients but note that they are micro-nutrients. Plants require a lot more of nitrogen, phosphorous, and potassium than they do any other minerals.

Trying to substitute Epsom salts for your regular fertilizer is not a good decision. If you want to use it as part of a homemade fertilizer, then that makes a lot of sense. But Epsom salt alone is not a good fertilizer for your plants.

Related reading:

Choosing A Fertilizer For Your Veggie Garden

How To Make Homemade Fertilizer

Does Epsom salt treat yellowing leaves on tomato plants?

Possibly. A magnesium deficiency can cause yellow tomato leaves. If the yellowing leaves are due to a magnesium deficiency, then Epsom salt may help your plants green up. However, using a balanced organic fertilizer will be more effective.

Yellow leaves with green veins indicate nutrient deficiency.
Yellowing leaves on a tomato plant.

Can Epsom salt be used for natural pest control?

Not effectively. There are some claims that Epsom salt is a deterrent for some garden pests like beetles and can kill slugs. Wouldn’t it be nice if pest control were that easy?

Unfortunately, there is no simple solution for pests in the garden. Hand removal of pests and frequent application of organic deterrents like neem oil and pesticides like Bt (for hornworms and caterpillars) are the best options for organic gardeners.

Related reading:

Organic Pest Control For Aphids

The Bugs In My Tomatoes

10 Things About Tomatoes Every Gardener Needs To Know

Have you heard other miracle claims for using Epsom salt with tomatoes?

I’d love to hear about your experience in the comments!

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  1. This was very interesting and I appreciate knowing more about the use of Epsom salt in the garden. I’ve used it a little bit, “just because.” I feel more knowledgeable about it now. I’m also a gardener and write about it. My grown son just recently started showing some interest in gardening, so I’m happy for you that your children are.

    1. If your soil needs magnesium, then Epsom salt can help. Otherwise, it’s not necessary. The only way to know if your soil is deficient in magnesium is to have a soil test done. I hope that answers your question.

    1. Hi, Jean! Tough skin can be caused by hot, dry weather. But sometimes it’s just variety specific. You can have your soil tested at your local county extension or use a mail in service using a kit like this one on Amazon

  2. My father always used Epsom salts on his fruit trees when I was younger and we always had big juicy fruit he put it on every few weeks from before flowers to fruiting but it could have been longer periods in between

  3. I use Epsom salts when we initially plant our our little plants from the greenhouse. I first dig my hole to the desired depth. I put 2 T of Epsom salts in the hole, then scratch the salts lightly to mix with the soil. Then I water my plant with a good soaking of water, with a water solvable organic fertilizer. Then every other week I dissolve 1 T of Epsom salts to my large sprinkling can, with the organic fertilizer, wetting the plant and leaves. This is the only time I allow the leaves to get wet, unless it rains. Once the fruit starts to set on well, I no longer add the Epsom salts. I know we have had no transplant shock to our plants, and see growth in the first week. I’m a believer, but I live along the Colorado Front range. The soil needs conditioning, but the organic fertilizer has helped.

    1. Hi, Kathy! Epsom salts definitely have their place in organic gardening. It’s just about knowing why they work so you can use them appropriately. I’m glad to hear you are having good luck with your tomatoes. That’s the most important thing! 🙂

  4. We fill our deep sunken bath with hot water, then add one cup of Epsom Salts, plus one tablespoon of bicarb, then relax in luxury for up to thirty minutes. Later, when the water has cooled, we pipe it down to our orchard and give each of our 100+ citrus trees a half-bucket each. The only other ‘fertilisers’ we add are SeaSol (a seaweed extract) and sheepsh*t. Our citrus trees (oranges, lemons, grapefruit, mandarins and tangelos) have all improved since we commenced this practice. Tomato plants? We use a blended mixture of coffee grounds, banana skins and eggshells. Tomato ‘trees’ thrive on this mixture!~

    1. Hi, Paolo! Great ideas. Sounds like you’ve found a great homemade fertilizer. The seaweed extract and animal waste are great for plants. Thanks for sharing!!

  5. Thank you so much for your insightful article! I’ve never used Epsom salts in my garden, and although I keep intending too, I’ve backed off because I didn’t feel I had enough information about the pros & cons. I’m truly grateful to you for giving me this clarification. As with all things in life, I find it’s best to just move slowly with changes, & if it ain’t broken, don’t fix it. I find that by doing my veggies and flowers in containers, I can provide each plant with just the right soil for optimum growth. I really appreciate your instructions. Thank you!

    1. Hi, Nikki! Thanks for your nice comments! Container gardening is a great way to get around all kinds of soil problems. So glad you’re having success with it!

      1. Containers? Please be careful… . A few years ago we created a large ‘container garden’, comprising over fifty large (100 litre) plastic crates. Elevated, these overcame problems with rabbits, roos and many other free diners. We grew most of our food in these containers. Alerted by friends to some of the dangers of plastics (See https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/bpa/faq-20058331 ) we switched to plastic-free raised gardens, recycling long lengths of metal roofing, to create long, high garden beds. These now provide year-long, BPA-free vegetables in season.

        I accept that suburban living restricts this kind of large scale project… but I’m concerned whenever I read that folk are using BPA-laced plastic containers, or chemically-treated wooden containers, to grow food. It’s just not worth the risk.

  6. I was just about to try epsom salts on my tomatoes and I’m glad I read your article. I have had an issue with blossom end rot in past seasons and don’t want to risk making it worse. Epsom salts did wonders for my roses however!

  7. Hello. Epson Salt definately works. My tomatoes are healthy, juicy and huge. I also sprinkle 1 cup Epson salt and 1 cup coarse salt around my citrus trees every 6 months and I have beautiful fruit. My Barberton Daisy plants just love the Epson salt water.
    Greetings from South Africa !

  8. Please give me measurements for making watering solution for my tomatoes. They are in containers. Thanks

  9. I, too, have wanted to use Epsom Salts in my garden but wasn’t quite sure how — Great artlcle!! I do have one question, however, how do you keep banana peels until you need them in your garden? in the refrigerator? I’d be afraid if I kept them on the counter, they would get moldy — and I struggle keeping used coffee grounds that long without them getting moldy…

  10. Hi Laura:
    Nice and informative article on use of Epsom salt in tomato and other garden plants! I thought I should correct a piece of information in the article — for the benefit of those who might need it for future reference: Magnesium (Mg) and Sulfur (S), which are plant nutrients contained in Epsom salt are actually “secondary macronutrients” and not micronutrients as presented in the article. They are next to NPK in the amount needed by garden plants. Where Mg and S are deficient, one expects Epsom salt to correct such deficiencies. Where soil/growth media tests show that these elements are adequate, Epsom salt is not likely to add any value to the growth of the garden plant.

    Do you have any information or experience on using Gypsum salt to correct Calcium deficiency and by extension, tomato blossom end rot?

    Thanks for sharing your article!

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