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What Plants Don’t Like Epsom Salt? [Answered]

Gardeners use Epsom salt on their plants in order to correct a magnesium deficiency and improve plant health. However, Epsom salt is not suitable for all plants.

Epsom salt has been used in gardens for many years as a way to add magnesium to soils that are deficient in this vital mineral. Many soils that are highly acidic (below a pH of 5.5) have a deficiency of magnesium. 

Clay soils are also subject to low levels of available magnesium. This is because the clay particles hold onto nutrients tightly and often, these vital nutrients are not available to the plants that are growing in these soils.

clay soil 1 | Plant care

That’s why gardeners have been using Epsom salt on their plants in order to correct this deficiency and improve plant health.  

However, Epsom salt is not suitable for all plants. In this guide, I’ll discuss some plants that definitely don’t like Epsom salt.

And after that, I’ll explain why I don’t use Epsom salt in my own garden.

Tropical palms

Tropical palms and, in fact, many types of tropical plants such as fiddle leaf figs, monstera and philodendron, don’t respond well to the use of Epsom salt. 

Monstera deliciosa | Plant care

It’s common practice for indoor plant growers to mix Epsom salt with water and then spray this on their plants. However, this could be harmful, especially those plants that have large leaves.

This is because the application of an Epsom salt solution to the leaves could result in leaf scorch. When you think about it, this makes perfect sense. 

Any high concentrations of one particular macronutrient such as magnesium are counterproductive to healthy plant growth. It’s far better to give your indoor plants an application of slow-release fertiliser twice a year and to add this to the soil.

This way, the plants can get the nutrients that they need in smaller doses. This prevents fertiliser burn and keeps the plants healthy and thriving.

Additionally, if you use a premium potting mix for your indoor plants, it’s unlikely that the mix would be deficient in any minerals anyway.

potting | Plant care

Tropical palms and other plants growing in the garden also don’t respond well to Epsom salt for the same reason. It can cause leaf scorch and is totally unnecessary. 

It’s far better to enrich the soil with lots of compost and apply a natural and organic fertiliser once or twice a year for optimum growth.

Conifers

Pine trees and other types of conifers are sensitive to magnesium chloride. This is a chemical compound found in Epsom salt. 

This means that if you have any type of conifer growing in your garden, you should refrain from using Epsom salt.

Insect-eating plants

Carnivorous plants such as Venus flytraps, pitcher plants and sundews are also not fond of Epsom salt and any application could quickly kill these plants.

pitcher plant | Plant care

The primary reason for this is that these plants have adapted to growing in mineral-depleted soils and will thrive in poor soils. 

This is similar to our Australian natives who have adapted to living in soils that are low in phosphorus. Feeding these plants with fertilisers that contain higher amounts of phosphorus can kill them.

Australian native plants

Although Epsom salt won’t generally harm our Australian natives, there’s really no good reason to use it either.

Grevillea juniperina | Plant care

As long as the pH level of the soil is above 5.5, there should be enough magnesium available for the plants to take up through their roots.

Why I don’t use Epsom salt in my garden

Although you’ll find plenty of information on the supposed benefits of adding Epsom salt and many gardeners will swear by it, I’ve never personally used it in my garden.

I’m not a fan of using any type of concentrated mineral or nutrient in my garden. Instead, I prefer a more sustainable gardening method that enriches the soil naturally and provides a healthy environment for plant growth.

That’s why I prefer to use only compost, well-rotted animal manures and organic fertilisers such as Dynamic Lifter or Blood and Bone in my garden. 

Cow manure | Plant care

You see, most plants need healthy soil to grow happily and thrive. Once we get this right, there’s really no need for additives to promote healthy plant growth.

And, to achieve healthy soil, you need to get the nutrient levels balanced and avoid adding single nutrient products that will unbalance the overall health of the soil.

Creating healthy soil should start with improving the pH level

As mentioned earlier, soils that are highly acidic may have a magnesium and even calcium deficiency.

In this case, you want to increase the pH level of the soil so that nutrients become more balanced and available to your plants.

One of the most natural ways to increase the pH of your soil is to use poultry manure. Or, you could opt for adding agricultural lime or dolomite, which are also natural minerals.

On the other hand, soils that are too alkaline can easily be improved by adding plenty of compost and other animal manure such as cow or horse manure.

Photo of author

Annette Hird

Annette Hird is a gardening expert with many years of experience in a range of gardening related positions. She has an Associate Diploma of Applied Science in Horticulture and has worked in a variety of production nurseries, primarily as a propagator. She has also been responsible for a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.

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