Should You Add Epsom Salt to Tomato Plants? Benefits and Myths

Our experienced writers spend hours deep researching, considering both scientific and experimental info to bring the insights you can trust.  

Quick Answer: Epsom Salt to Tomato Plants

Epsom salt acts as a natural vitamin and fertilizer on tomato plants. Indeed, it is a natural nutrient that strengthens the roots and helps plants absorb chlorophyll and regenerate quickly.

In this post, we’ll see what Epsom salt or magnesium sulfate does to tomato plants and what it cannot do.

The plants will be stronger, fuller, their leaves do not turn yellow, and the fruits are larger. Epsom salt is ideal for soils low in magnesium and sulfur.

Let’s get started to find out the full benefits of Epsom salt for fertilizing tomatoes and the little caveats!

What is Epsom Salt?

Epsom salt is also known as “magnesium sulfate” and is mostly offered in solid form. In pharmacies, it is usually offered as a white, crystalline powder or in the form of shiny, colorless crystals.

For several centuries, it has been renowned for its many health benefits for direct human consumption.

It is also beneficial for the garden and, more particularly, for the vegetable patch. Like us, plants sometimes lack the nutrients to thrive.

Do Tomato Plants Benefit from Epsom salt?

Tomato plants can benefit a lot from Epsom salt. This magnesium sulfate promotes growth and keeps pests away.

To analyze, tomato plants grow well in loose soil such as sandy and loamy soil. Magnesium is a requirement for plants to grow. It is usually found in sufficient quantities in the soil.

However, in sandy soils, the magnesium is easily washed out of the soil by precipitation. An annual loss of around three grams per square meter usually occurs.

In loamy soils, the loss is usually less because the magnesium can accumulate on the clay minerals it contains. However, it is usually quickly noticeable when the plants are receiving too little magnesium.

With a magnesium deficiency, not enough chlorophyll will be produced. Remember in biology classes? Chlorophyll is essential in photosynthesis as it produces green pigments.

So, the following symptoms may occur:

  • Poor stunted poor growth
  • Leaves turn yellow
  • Later, the leaves turn rusty brown

What does Epsom salt do for tomatoes? 3 Benefits

Here are some of the key benefits of Epsom salt on tomato plants.

1. Fixes yellow leaves and mottling patterns

Some of the signs of magnesium deficiency in tomatoes are yellowish leaves and the appearance of mottling patterns with green veins.

After all, magnesium is essential for photosynthesis and a central component of chlorophyll. Epsom salt is ideal for acute magnesium deficiency.

With Epsom salt, your tomato plants will benefit from the high magnesium content.

Magnesium is involved in the build-up of sugars, from which the plants, in turn, produce cellulose and other endogenous substances.

2. Epsom salt for tomato plant growth

You can also put a large teaspoon of salt at the foot of tomato plants to boost the roots. With each watering or rain, the salt will penetrate the soil.

This application, once every month, is ideal for tomato plants, peppers, and even for roses as it boosts their growth. Epsom salt also makes tomatoes juicier and sweeter.

Also, if there is a suspicion of a magnesium deficiency, tomatoes can be fertilized quickly and easily with Epsom salt. The use of Epsom salt can correct the stunted growth caused by a deficiency in magnesium.

Plants love magnesium because it strengthens the cell structure, and if it has a stronger cell structure, it will produce more yield, and it’s more disease resistant.

Since Epsom salt is easily soluble in water, it is advisable to use it in liquid form in a one percent Epsom salt solution.

For this purpose, about 10 grams of Epsom salts are mixed with one liter of water and then sprayed directly onto the leaves.

The advantage here is that the leaves absorb the nutrients directly, and the fertilization works particularly quickly.

But be careful: When fertilizing with Epsom salt, the following should be observed:

  • Do not spray tomatoes in the blazing midday sun, as parts of the plant could burn
  • Spray off with water after spraying

Note: The mixture should always be selected carefully, as over-fertilization with magnesium can cause a potassium deficiency.

3. Epsom salt as sulfur fertilizer

Leaf chlorosis (yellowing) is also a sign of sulfur deficiency in tomatoes. Epsom salt is primarily characterized by its high magnesium content.

However, magnesium sulfate also contains sulfur, another important nutrient for tomatoes.

Sulfur deficiency is relatively rare these days, especially if the soil is regularly enriched with compost or rotted cattle manure.

However, it can still happen that tomatoes do not receive enough sulfur.

Also, sandy soils are usually deficient in sulfur. In this case, Epsom salt can also be used as a sulfur fertilizer.

A sulfur deficiency can be determined in tomatoes as follows:

  • Resembles nitrogen deficiency
  • The leaves and veins turn yellow
  • Mostly only affects young leaves

The Myths: What Epsom Salt Cannot Do

There have been a lot of other claims on what Epsom salts can do, most of which are not true – or are not yet scientifically proven.

1. Epsom salt Doesn’t prevent diseases

There have been claims that Epsom salt helps against diseases and pests.

However, scientific research involving tests on various diseases has shown no evidence that magnesium sulfate helps plants be disease-free.

Epsom salt is said to prevent blossom end rot, but this is untrue. Improper use or overdose of Epsom salt can cause blossom end rot.

2. Epsom salt is NOT needed for seed germination

Many gardeners think Epsom salt promotes seed germination in the tomato garden. But that’s not true.

Tomato seeds are different from other vegetable seeds. They contain the needed nutrients for germination.

Therefore, additional nutrients such as magnesium are not needed and may even cause problems such as blossom end rot.

Epsom salt may, however, be helpful when transplanting seedlings. But when the seed is just germinating, it’s needless.

How to Apply Epsom Salt to Plants (Step by Step Method)

You don’t just buy Epsom salt and head over to your garden for immediate application. Epsom salt can be fatal to the life of your tomato plants.

It’s always best to start by analyzing the composition of your soil.

1. Conduct a Soil analysis (as thorough as possible)

If you want to optimally adjust the fertilization to the soil, you should have a soil analysis carried out before using Epsom salt.

Several samples are taken from the soil and then passed on to experts for analysis.

The soil analysis provides information about the composition of the soil as well as instructions on how to fertilize.

To carry out a soil analysis, you need a special analysis set from a specialist retailer. Hobby gardeners then proceed as follows:

  • Take soil samples at various points
  • A total of about 15-20 samples
  • Record detailed information in a sheet
  • Send the container with the registration sheet to the laboratory
  • The samples are analyzed in the laboratory

Note: A soil analysis costs around $50 and is valid for around five years. For this reason, it is advisable to do a soil analysis every five years.

Here is how you can do it –

What does soil analysis test for?

You need a professional soil analysis that goes far beyond the determination of the pH value.

The result provides a precise overview of the composition of soil nutrients such as magnesium, nitrogen, potassium, phosphorus, copper, iron, and boron.

At the same time, the experts provide a detailed fertilizer recommendation.

If the soil analysis shows that the garden soil can no longer supply the plants with sufficient nutrients, the hobby gardener compensates for this deficiency with fertilizer.

A magnesium deficiency often occurs where light, acidic soil is planted with rhododendrons, azaleas, and similar plants.

How much Epsom salt does your tomato plant need?

Depending on the consistency of the potting soil, the magnesium contained in the soil is washed out every year with the natural amount of rain and irrigation water.

On average, the washout averages 7 to 8 grams per square meter, an order of magnitude that should not be taken lightly.

These minimum levels of magnesium should be present:

1. Light, sandy, and medium, loamy soil: 4 to 6 mg or one tablespoon of magnesium per 100 g of soil.
2. Clay and loamy, heavy soil: 6 to 9 mg of magnesium per 100 g of soil.

Given these values, the experts will usually only recommend annual, low-dose maintenance fertilization with
Epsom salt of 50 grams per square meter to replace the portion washed out by precipitation.

Epsom salt for Acute Magnesium Deficiency

If, on the other hand, the soil analysis revealed an acute deficiency of magnesium in the garden soil, Epsom salt can also be used as fertilizer.

The dosage depends on the nature of the soil and the amount of magnesium present per 100 g of soil.

In general, the recommendations are as follows:

Light to medium soil: 2-3 times per season approx. 30 g Epsom salt fertilizer per square meter.

Heavy, loamy soil: 30 g Epsom salt fertilizer once per season and square meter.

Note: These are merely average empirical values and do not replace the detailed dosage recommendations of a qualified laboratory.

How to use Epsom salt as fertilizer

Dissolve the Epsom salt in water according to the manufacturer’s instructions. Apply immediately to plants using the garden sprayer. Alternatively, apply into the soil as granules and then water well.

Epsom salt can also be used as a foliar fertilizer (sprinkled on the leaves).

Dilute a large teaspoon of salt in 1 liter of water and spray the mixture on the leaves of your green plants once or twice a month. They will be more vigorous and greener because the salt activates photosynthesis.

Check out the video below to see how Epsom salt is applied to plants:

Tip: The Epsom salt is not applied outside of the growing season, because in this case, it seeps into the ground without any effect and only pollutes the groundwater.

Warning: Never apply magnesium sulfate directly to the roots as it can cause burns there


What is Epsom salt composed of?

Epsom salt is magnesium sulfate. It consists of magnesium and sulfate, which is, simply put, sulfur.

On average, Epsom salt consists of 16% magnesium and 13% sulfur. However, these levels can vary from provider to provider or depending on the product used.

You can always find the exact content of your Epsom salts on the packaging. Magnesium sulfate is essential for tomato plants, which is why fertilization with Epsom salt is often recommended.

What are the side effects of Epsom salt?

An overdose of Epsom salt comes with a lot of negative side effects. Some of these include soil toxicity, leaf scorch, blossom end rot, a long-term deficiency in potassium, and outright death of the tomato plant.

How often should I spray my plants with Epsom salt?

For fertilizing with Epsom salt, however, there are guidelines that hobby gardeners can adhere to. For light and medium soils, fertilize 2 – 3 times per season.

Apply about 30 grams of the solution per meter square. In heavy soils, fertilize once a season. Apply about 30 grams per meter square.

Will Epsom salt kill tomato plants?

An overdose or misuse of Epsom salt can kill the plant. That’s why soil analysis is often recommended before spiking the soil with magnesium sulfate.

It can begin with calcium deficiency and blossom end rot which is truly a garden disaster no one wishes for.


Yes, Epsom salt offers many benefits to tomato plants, but it is high time the myths are busted in good time as a misuse of Epsom salt can be the end of your plant.

We hope you now know these benefits, myths, and procedures for use. If you find the article useful, kindly share!