Are you looking for a solution to save that sad-looking houseplant, or do you need help getting your garden to bloom? The answer may be simpler than you think, and you may already have this product in your cupboard. Many gardeners turn to Epsom salt to get their potted plants and gardens to bloom. But should you use Epsom salt on your plants?

We went straight to the experts to learn more about this gardening trick and how to use it correctly to unlock your plants’ full potential.

What effect does Epsom salt have on plants?

“Epsom salt, also known as magnesium sulfate, is a popular garden remedy that replenishes important nutrients such as magnesium and sulfur in the soil,” says Omelchenko. “Magnesium plays a crucial role in photosynthesis as part of the chlorophyll molecule, while sulfur is essential for the synthesis of amino acids, vitamins, proteins and carbohydrates.”

She adds: “Whether you need to use Epsom salts depends on the condition of the soil and the plants.”

Why you should use Epsom salt in your garden

Heinrich, a gardener and botanical designer, says plants need 6 major nutrients and 11 minor nutrients to be healthy and thrive. “Let’s say you have healthy, fertile soil that is regularly amended with organic compost and fertilizer,” he says. “In this case, you probably don’t need to add any industrially produced fertilizer to the soil because it already contains everything your plants need to grow strong and healthy.”

However, if you have poor soil that isn’t rich in nutrients, you may need to fertilize it with the three most important macronutrients nitrogen, phosphorus and potassium (also known as NPK), as well as the three less important macronutrients magnesium, sulfur and potassium, explains Heinrich. “As you can see, Epsom salt – magnesium sulfate – contains two of these less important macronutrients,” he says.

He adds, “Epsom salt helps your plants absorb all the other nutrients from the soil. Your plants will have healthier looking leaves and it can even improve the flavor of your fruits and vegetables, making them sweeter and more nutrient-dense.”

Benefits of using Epsom salt on plants

Omelchenko says that using Epsom salt can benefit plants in many ways. For example, if a plant is suffering from a magnesium deficiency, its leaves can turn pale and yellow – a condition known as chlorosis. Epsom salt can prevent this by providing the necessary magnesium. Because Epsom salt promotes chlorophyll production, it can also help foliage to become green and lush. Some gardeners also report that Epsom salt helps increase flower and fruit production.

She also states that a lack of sulfur inhibits the synthesis of proteins, carbohydrates and other substances needed by the plant. “Sulfur is part of enzymes and other compounds necessary for nitrogen assimilation, and its absence can hinder nitrogen metabolism,” she explains. “This, in turn, can lead to chlorosis due to nitrogen deficiency and slow growth.”

She further explains: “Epsom salt can increase the sulfur content, which helps the plant to grow and develop more vigorously. In addition, sulfur affects the quality of the crop by improving the protein and oil content of the fruit.”

Heinrich says if you have a new garden plot with unimproved soil that is rich in natural nutrients and minerals, Epsom salts are a great way to enrich your plants with some of the vital nutrients they need to thrive.

Epsom salt is also beneficial for potted vegetables. “Tomatoes and other vegetables can quickly absorb nutrients from the soil in pots. That’s why supplementing with Epsom salt and other water-soluble fertilizers is important to keep your potted plants healthy and vital,” he informs.

Disadvantages of using Epsom salt on plants

“Epsom salt may seem like a miracle cure, but it can have its drawbacks and should be used with caution,” advises Omelchenko. She continues, “If your soil is already rich in magnesium, adding Epsom salt can cause an imbalance by interfering with the absorption of other minerals such as calcium and potassium. Excessive use of Epsom salt can lead to salinization, which can negatively affect plant health by making it difficult for plants to absorb water and nutrients.”

She adds: “This can lead to drought stress symptoms, nutrient deficiencies and, in severe cases, plant death. Excessive use of magnesium sulfate can also contaminate local water sources.”

Heinrich warns that overusing Epsom salt in your garden will stunt the growth of your vegetables or even burn them. “You should use (Epsom salt) sparingly and only twice during the growing season. Once you’ve enriched your soil with organic compost and fertilizer, you may only need to fertilize with Epsom salt once in the middle of the season,” he explains.

How to determine if your plants need Epsom salt

Although Epsom salt has benefits, you need to be sure your plants really need it before you start supplementing your flora. Omelchenko says the best way to do this is to do a soil analysis. Soil tests can provide information about pH and nutrient levels.

She also advises checking your plants for signs of magnesium deficiency. “Watch for symptoms such as intercostal chlorosis, which is characterized by light green and then yellow spots and streaks between the green leaf veins. The leaf edges can turn yellow, orange, red or dark red,” she informs.

She continues: “Signs of magnesium deficiency first appear on older leaves and then spread to younger leaves and other parts of the plant.”

How do you use Epsom salt on plants?

So how do you use Epsom salt when your plants need it? There are actually several ways to use it for your plants. But before you reach for that bag of Epsom salt, you need to make sure it doesn’t contain any additional ingredients that aren’t good for plants. It’s best to use unscented, plain Epsom salt for internal and external use on plants.

Nevertheless, the experts recommend some simple application methods:

Spray the leaves

Omelchenko says that Epsom salt can be used as a foliar fertilizer by spraying the solution on the leaves. This method is especially effective for quickly treating magnesium deficiency.

“To make an Epsom salt solution, mix 1-2 tablespoons of Epsom salt with 1 gallon of water. You can use this solution to spray the leaves or water the soil,” she says. “It’s important to remember that different types of plants have different leaf thicknesses. Some have thicker protective layers, while others are more delicate and sensitive to treatments.”

She continues, “For foliar applications, it’s a good idea to test the solution on a few leaves of each plant before spraying the entire plant. This will allow you to observe and make sure the solution is not causing chemical burns, which appear as yellow or light brown dry patches. If you notice patches, add more water to the solution to dilute it. Perform the treatment once a month.”

Pour it into the soil

Another method of applying Epsom salt to plants is to mix it with water and pour it into the soil. Omelchenko says you should avoid adding dry Epsom salt directly to the soil, as this can cause soil salinization and chemical burns. Dissolving it in water ensures that the roots can properly absorb magnesium and sulfur, which promotes healthy growth without harming the plants.

“It is important not to do this too often or in high concentrations to avoid chemical burns and other negative effects,” says Omelchenko. “As with other fertilizers, I recommend watering the plant abundantly a few hours before application to avoid burning the roots, which are more vulnerable in dry soil.”

Heinrich says the most common mistake people make when using Epsom salt in their garden is using too much of it. “All you need to do is add one tablespoon of Epsom salt to a gallon of water and pour it into the root zone of your cucumbers, tomatoes, eggplants, melons and other vegetables,” he informs. “This fertilization should only be done twice a year: once when the plants are first planted and again halfway through the growing season.”

He continues, “If you fertilize every other week or several times a month, as some gardening influencers have suggested, your plants will not be able to effectively transport nutrients from the roots to the leaves and fruit.”

Much like seasoning food, you don’t want to add too much salt to your plants. But with these expert tips, you can give your plants the right amount of Epsom salt to make them look lusher in no time.