Is Epsom Salt a Good Fertilizer? A Detailed Analysis

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Epsom salt is a naturally occurring compound made up of sulfur, magnesium, and oxygen. Magnesium and sulfur are essential secondary nutrients plants need to thrive and bloom. Since Epsom salt contains these nutrients, does it make a good fertilizer?

Epsom salt is a good fertilizer since it contains magnesium and sulfur nutrients. Plants need these nutrients to bloom, thrive, and produce more chlorophyll. Therefore, fertilizing your plants with Epsom salt is an excellent way to boost their growth and production.

In the rest of this article, I’ll discuss why you should fertilize your plants with Epsom salt. I’ll also cover how to fertilize with Epsom salt and its benefits to your plants. Let’s get started!

Should You Fertilize Plants With Epsom Salt?

Fertilizing your plants with Epsom salt is one of the best decisions you can make. Your plants need an optimum supply of nutrients to grow to their full potential. Epsom salt supplies magnesium and sulfur, some crucial nutrients your plants need for their well-being.

According to the fertilizer ratio, regular fertilizers are abundant in nitrogen, phosphate, and potash. Therefore, although you can argue that standard fertilizers are enough, your plants still need magnesium and sulfur.

To this end, it’s worth clarifying that fertilizer is not food for your plants. Therefore, they should grow even without being fertilized. However, they will not attain their maximum potential in terms of size, color, and production.

It’s worth noting that plants undergo photosynthesis to manufacture their food in the form of sugars. However, you must fertilize them to provide the necessary nutrients for photosynthesis. I hope it’s clear why you should consider fertilizing your plants with Epsom salt.

Tip: I’ve written in-depth articles about why plants need nitrogen, phosphorus and potassium. Check them out!

How To Fertilize With Epsom Salt

Like any other fertilizer, using Epsom salt to fertilize your plants requires you to adhere to some guidelines for efficient results. You must know what to do and what not to do for the safety of your plants.

The following guide will help you fertilize with Epsom salt the right way:

Test the Soil

Soil testing entails determining the nutrient levels in your soil. The test will help you know what nutrients are lacking so you can add them. Adding the wrong nutrients to your soil can damage your plants.

In the context of fertilizing your plants with Epsom salt, your focus is to know if the soil is deficient in magnesium or sulfur. These are the essential nutrients your plants will get if you fertilize with this salt.

You can buy a soil test kit from your local nursery or agricultural store if you want an accurate reading of your soil’s nutrient levels. The kit should have all the tools you need for a precise test, including the instructions.

Once you have the soil test kit, follow the instructions on how to go about the testing. It would be best if you did this a few weeks before planting so you can make the necessary changes to your soil’s nutrient levels.

After testing the soil, you should decide whether to fertilize your plants with Epsom salt or not. You can fertilize with salt if the test results show that the soil lacks magnesium or sulfur.

If the results are satisfactory, it means your soil has the optimum levels of nutrients, and you don’t need to fertilize.

Determine How Much Epsom Salt To Use

After testing your soil and deciding to fertilize it with Epsom salt, the next step is determining how much salt to use.

The amount of salt you’ll use depends on your soil test results and the type of your plants. As a rule of thumb, you should mix one to two tablespoons of Epsom salt in a gallon of water. Here is a general procedure:

  1. Make a paste of Epsom salt by mixing one to two tablespoons of the salt in warm water (Using more Epsom salt will not be effective).
  2. Shake to mix the components.
  3. Apply the mixture to your plants regularly during the growing season (spring). You can spray the mixture on the leaves or apply it to the roots.

Expert Tip: Overfertilizing your plants with Epsom salt leads to darker leaves and stunted growth. Therefore, you should stick to the recommended amount for your plants’ safety.

Specific Epsom Salt Amount for Different Plants

If you want to be specific with the amount of Epsom salt you apply to your plants, this guide is for you: 

  • Lawns: Use three pounds (1.36 kg) of salt for every 1,250 square feet (116.13 square meters).
  • Potted plants: Two tablespoons of salt for every gallon (3.79 liters).
  • Trees: Two tablespoons of salt for every nine square feet (0.84 square meters).
  • Roses: One tablespoon of salt for every foot (30.48 cm) of the plant height. This means you should measure all your rose plants before applying.

If you decide to mix the Epsom salt with water, applying it as a foliar spray is the best option. Foliar feeding is a process of applying nutrients directly to the leaves. The plant’s leaves have pores that enable them to absorb nutrients quickly when sprayed. This makes the nutrients readily available for use by the plant.

Benefits of Epsom Salt for Plants

Fertilizing your plants with Epsom salt has the following benefits:

Enhances Nutrient Uptake

Magnesium in Epsom salt is a crucial component in the uptake of nutrients by plants. In plants, magnesium acts as a phosphorus carrier.

On the other hand, sulfur aids in the absorption of other nutrients, such as nitrogen and phosphorus. Sulfur is also a key player in plant metabolism and synthesis processes. 

Makes Plants Greener

Plants need magnesium to secrete chlorophyll. Chlorophyll is the green pigment in plants that helps them to photosynthesize food.

As such, a magnesium deficiency will lead to Chlorosis (the yellowing of the leaves). Fertilizing with Epsom salt is an excellent way to green up your plants and make them lusher. Therefore, it’s your go-to option if you want to enhance your lawn’s lushness.

Repelling Pests

Pests like slugs and voles are a nuisance in any garden. They not only damage your plants but also make your garden look unkempt.

Epsom salt deters these pests by dehydrating them when they ingest it. The salt works by drawing water from the pests’ bodies through osmosis. This process eventually leads to the death of the pest.

You can also use Epsom salt to repel rabbits and deer from your garden. These animals don’t like the taste of magnesium sulfate, so they will avoid eating your plants.

However, you should not use Epsom salt as your primary pest control method. Some pests can develop a tolerance to salt. Therefore, you should use it with other pest control methods for the best results.

Neutralizes Soil pH

Your soil’s pH is crucial for the well-being of your crops. A high soil pH (alkaline) is always deficient in essential minerals like zinc, manganese, copper, and boron.

On the other hand, a low soil pH (too acidic) increases the impact of toxic elements on plants. It also decreases the availability of essential nutrients.

Epsom salt can help to neutralize your soil’s pH and make it more hospitable for your plants. A conducive soil pH for most plants ranges from 5.5 to 7.5.

It’s worth noting that you should test your soil’s pH before adding Epsom salt. This will help you determine the right amount of salt to add.

You can use a simple pH soil test kit or take your soil sample to a gardening center for testing.

Improves Flower Blooms

Epsom salt is a particularly beneficial fertilizer for flowers. The magnesium in the salt helps to create more vibrant and plentiful blooms.

If you want your roses to bloom more, applying Epsom salt is an excellent way to achieve this. It’s advisable to use the salt when the plants are actively growing for the best results. This is usually in spring and summer.


Fertilizing with Epsom salt is an excellent way to provide magnesium and sulfur to your plants. However, you should always test the soil to know what amount to use. Excessive fertilization can be catastrophic for your plants.

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