What Does Epsom Salt Do for Tomato Plants?

Learn the benefits of Epsom salt for tomato plant growth, how to apply it properly, and how much salt to use for optimal results.

Sean Stratton | Updated January 21, 2023
garden of tomatoes

Epsom salt helps restore the levels of micronutrients in the soil. This will result in pushing the growth of your plants, improving the flavor of the tomatoes, and better tomato yields.

In this guide, you will learn the benefits of using Epsom salt for tomatoes and many other relevant things that you should know while using Epsom salt for tomato plants.

What Does Epsom Salt Do for Tomato Plants?

Probably you have got some brief ideas about why you need Epsom salt for your tomato plants. Now, let’s talk about them in detail.

1. No More Yellow Leaves

Imagine you woke up one morning and found out all of your vibrant green tomato leaves turned yellow. It’s more like a living nightmare, right? There can be various reasons behind this, including the lack of magnesium.

And if your plants are lacking in magnesium, consider they are suffering from chlorosis and as a result, they are unable to produce enough chlorophyll. A quick fix would be to use magnesium. As Epsom salt contains magnesium as its main component, using the salt immediately can help improve the condition of your tomato plants.

2. Better Flavor

Ever tasted that ketchup that tastes like “nothing”? Well, you shouldn’t blame the one who prepared it; probably there is something wrong with the tomatoes. The nutrients on the soil may impact the taste of the tomatoes.

And what will be a better option than Epsom salt when it comes to providing the nutrients to your tomato plants? From Epsom salt, you will get two vital micronutrients to feed your plants.

Firstly, Magnesium will help your plants in photosynthesis so your plants will be able to collect more food directly from the sun. On the other hand, sulfur will help produce protein and enzymes.

Epsom salt will ensure both of the benefits for your tomato plants. So, if you manage to apply the salt in a sufficient amount and provide other nutrients in time as well, you can hope for tastier tomatoes this harvesting season.

3. Growth Improvement

Epsom salt benefits tomato plants in many ways and improving their growth is one of them. If you can ensure proper nutrients, you are more likely to get a better tomato yield. And the vital nutrients that your plants need include magnesium.

It plays a vital role in photosynthesis because you can’t think of chlorophyll production without magnesium. That’s why if your plants lack magnesium, they will lack chlorophyll and ultimately this will result in impacting the natural rate of photosynthesis.

You may also notice that your plants are getting enough sunlight still they are not healthy as they should be. This could be an indication that your plants are not getting enough micronutrients, especially magnesium.

So, the first thing you should do if you encounter this is to make sure whether your plants are lacking magnesium or not. If the reason is magnesium, Epsom salt is the thing you need.

How Do You Use Epsom Salt on Tomato Plants?

You’ve already got some rough ideas about the benefits of using Epsom salts on your tomato plants. But we haven’t answered another relevant question that naturally comes with our topic; how to use Epsom salt on tomato plants?

Epsom salt application on tomato plants can be divided into four categories in general. Let’s check them out.

1. At the Time of Planting

To give your tomato seedlings a head start with nutrients, applying the Epsom salt at the very beginning will be a better idea. And to do that, you need to put just 1 tablespoon of Epsom salt at the bottom of each planting hole.

Sometimes, you may need to use 2 tablespoons per planting hole but make sure to ask a local expert gardener before doing this.

2. Foliar Spray with Epsom Salt

You can help your plant beat magnesium deficiency by spraying a mixture of water and salt. And there are benefits of foliar applications during the season because they may work faster than soil applications. You need to start this application from the first appearance of the bloom. 

All you need to do is to take 1 tablespoon of salt in a gallon of water and spray on your plants using a spray bottle. You don’t need to do it more than once a month, overdoing it may harm the plant.

3. Side-dressing with Epsom Salt

You need to start this application when you notice the leaves are starting to appear. 1 tablespoon of salt is enough for a 1-foot-tall plant. If your plant is 2 feet tall, you will need to increase the amount of Epsom salt according to the height of your plant which will be 2 tablespoons. For even larger plants, increase the amount accordingly.

You need to apply the salt just around the plant’s base, no need to go too much further away from the base. Gently work in the outer layer of the soil and make sure you do not cause any damage to the young, developing roots of the plant.

You will need to repeat this Epsom salt application cycle approximately after every 42 days; to be more specific – six weeks. You need to continue this cycle to the end of the harvesting season.

4. Epsom Salt for Potted Plants

For potted plants, the application process will be quite the same. You just need to take 1 gallon of water and 2 tablespoons of salt and mix them well. Now, simply apply the mixture to your plants once every month. The plants don’t need this more, don’t overdo it.

How Often Should I Put Epsom Salt on My Tomato Plants?

After seeing all those benefits, if you are thinking of applying Epsom salts on your tomato plants every now and then, probably you are thinking the wrong way. Applying Epsom salt frequently will not bring benefits.

Now, coming to the time of application: well, this may depend on various factors. But you should know that your plants won’t need Epsom salt that much; applying it once a month will be fine. But if your plants are like two feet tall, you will probably need to feed them with Epsom salt twice a month.

But before applying Epsom salt to your plants, don’t hesitate to seek help from a local expert gardener because the application time and the amount of salt may vary according to the quality of the soil, health conditions of your plants, etc. One more thing: never overuse the salt.

Can You Put Too Much Epsom Salt on Tomato Plants?

No, you shouldn’t use too much Epsom salt on your tomato plants. Applying too much salt can cause the opposite of benefits.

For example, if you add too much Epsom salt to your plants, the first thing it will impact is the balance of the nutrients on the soil.

To understand things in detail, think of it this way: if you add too much salt, the chemical element – magnesium will be increased in the soil proportionally because it is the main component of Epsom salt. This will ultimately damage the balance of other nutrients in the soil.

There are other problems as well, like if the magnesium in the salt somehow competes with the calcium in the soil, you may end up with other serious issues. And to scare you a bit, know that end rot occurs due to the lack of calcium!

And that’s not all; you could encounter more problems just because of not controlling yourself while applying the Epsom salt!

How Much Epsom Salt Do You Put in a Gallon of Water for Tomatoes?

Epsom salt is water-soluble, so you don’t need to worry too much about mixing the salt in the water. And for the amount of salt, you will need 1 to 2 tablespoons for each gallon of water.

Will Epsom Salt Kill Tomato Plants?

It’s possible if you take the salt application at the worst level. Too much application of the Epsom salt may result in damaging your plants.

A simple example to demonstrate this will be something like this: the soil should maintain a certain level of calcium more than magnesium.

If you apply excessive Epsom salt on the soil, it will result in more magnesium in the soil and more magnesium means less calcium because when it comes to uptake, they may compete with each other. As a result, this may end pretty badly.

Final Thoughts

If your plants are suffering from nutrient deficiency and struggling to survive, Epsom salt can be a great way of restoring the balance of magnesium and other nutrients on the soil. It will help your tomato plants fight diseases like yellow leaves, improve growth, and even improve the taste of the tomatoes.

However, there are some hoaxes about Epsom salt like it will prevent blossom end rot, and the reality is that they won’t. But putting all the hoaxes aside, Epsom salt is a great mineral compound for your tomato plants that you need to use in a very limited amount.

Written by Sean Stratton

Sean Stratton

Hi, I'm Sean, the senior editor here at Fertilizer Pick. I grew up on a farm in North Carolina and have grown fruits, vegetables, and trees since childhood. While I no longer live on a farm today, I still enjoy spending time on my garden and sharing my knowledge with friends and fellow garden enthusiasts.