Using Epsom Salt on Plants

Using Epsom salt on plants has been the secret to growing sweeter fruit and vibrant houseplants for years. It’s a cheap, non-toxic, and natural supplement for any garden. You can find it in almost any grocery or drug store and online.

So if you want bigger, healthier plants, you better listen up.

A scoop in epsom salt
Epsom salt can look like table salt, but it has quite the bitter taste.

Epsom Salt Benefits

Epsom salt, or magnesium sulfate, adds magnesium and sulfur to the soil. Using Epsom salt on your plants does many wonderful things for your plants, including but not limited to:

  • Improving flower blooming
  • Making plants bushier
  • Adding vibrancy to the foliage
  • Boosting flavor in crops such as tomatoes
  • Preventing less pest damage
  • Germinating stronger seedlings

Epsom salt also doesn’t build up like commercial fertilizer or poison your groundwater, so you don’t have to worry about using too much. Well, you do, just not as much.

Safety Precautions

First off, don’t forget your gloves!

Although Epsom salt is non-toxic, it does have natural laxative properties, so keep it away from pets, children, or anything without self-control.

The only ingredient on the package should be Epsom salt or magnesium sulfate. Do not use Epsom salt that is colored or scented. The dye and fragrance can damage your plant. We are trying to help your plant, not kill it. So keep that in the bathroom.

Only use salts marked by the USP (United States Pharmacopeia). The salt is tested and certified by the FDA and the USP, so you can trust that it’s not harmful to you or your plants.

And finally, and I can not stress this enough..

Always test your soil before using Epsom salt or any DIY supplement on your plants. Only use Epsom salt if the soil is low in magnesium. I know it’s tedious and boring, but using Epsom salt on your plants without really knowing what’s in it can ruin your soil (And your plants!)

 Closeup of hands spraying plant

Applying Epsom Salt

Epsom salt absorbs really well when diluted with water. It also works really well as a foliar spray!

Water with either a drench of:

  • Two tablespoons (30 mL) to one gallon (3.785 L) of water every month, or…
  • One tablespoon (15 mL) to one gallon of water every other week

Before planting, you can also work in some salt to give your plants a boost!

Ways to Use Epsom Salt

There are a variety of ways to use Epsom salt on your plants. Here are a few ways to use it to get the most out of your garden.

Close up of tomato seedlings

1. Start stronger seedlings

Magnesium boosts seed germination by strengthening cell walls. It also provides energy and sulfur, which can be easily lost during germination. Apply a drench of one tbsp of Epsom salt/gallon of water solution after sowing.

2. Increase Nutrient Absorption

Magnesium help plants to better take in important nutrients like nitrogen and phosphorus. One recent study indicates that magnesium sulfate can increase cell uptake of important nutrients, including nitrogen, phosphorus, and sulfur.

In the study, testers in five states gave pepper plants a drench of one tablespoon Epsom salt to one gallon of water twice a month. And a majority of the pepper plants showed thicker foliage and larger crops.

Close up of a bunch of basil and a grey background

3. Add Vibrancy to Your Leaves

Older leaves are more likely to have a magnesium deficiency and turn yellow. This is because of the degrading of chlorophyll in the leaves. If you notice mature leaves turning yellow or yellow with green veins, try a foliar spray of one tbsp Epsom salt to four cups (1 L).

Closeup of holding a plant with roots showing

4. Prevent Root Shock

If your cuttings are wilting and turning yellow after being transplanted, it’s root shock. A way to help prevent root shock is to apply a drench of one tbsp Epsom salt to one gallon of water to newly repotted roots until saturated.

5. Use as a weed killer

A simple concoction of two cups (500 mL) of Epsom salt, one gallon of vinegar, and a bit of dish soap is a great alternative to weed killer. Spray it on weeds without killing other plants.

A slug

6. Use as Pest Control

Slugs munching on your precious leaves? Not to worry, sprinkle a bit of Epsom salt where slugs slide by (Haha, get it?), and the slugs will be no more!

A vine of cherry tomatoes against a gray background

7. Boost the Flavor of Your Crops

During the growing season, water with an one tbsp Epsom salt to one gallon of water solution once a month. Doing this regularly will make your crops bigger, and tastier.

When Not to Use Epsom Salts

Epsom salts seem to be a solution to all of your problems whether it is slimy slugs or college debt. But there are times where Epsom salt isn’t necessary.

Gloved hands holding fertilizer

As A Replacement for Main Fertilizer

Epsom salt’s value is 0-0-0. Which means it has no traces of N-P-K (nitrogen, phosphorus, and potassium) in it. It should not be a replacement for a balanced fertilizer. Use it only as a secondary supplement.

Close up of dirt

To Neutralize Acidic Soil

Epsom salt makes things more acidic. So it’s nice for neutralizing alkaline soil. But if your goal is to neutralize acidic soil, it could make things worse. If worse comes to worse, pop in a few azaleas.


Phew! And that’s how to use Epsom salt on plants. I bet you never knew how amazing Epsom salt is for your plant. If not, then I assume you have studied salt all your life.

Honestly, I’ve been talking about salt so long I think it’s time I go on a low sodium diet.

Happy Gardening! Till we meet again.

Psst! If you want to learn more about plants, subscribe to my Plant of the Month Newsletter!

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