Epsom salts for garden pests: So crazy it might just work

No one likes it when insects ruin a garden. Many gardeners have home remedies they swear by, and chief among those remedies is Epsom salt. Does it actually work, though? If so, how and in what ways can it be used?

In this simple guide we’ll break down the five most common uses for Epsom salt in the garden, including what drawbacks there may be to adding salt to your landscape.

Repelling pests

Epsom salt has garnered quite the reputation for repelling pests. Folks often lay a line of Epsom salt around their gardens, or individual plants. The idea behind it is that soft-bodied insects, like slugs and snails, won’t cross salt surfaces as it draws the moisture from their body, slowly killing them.

For many gardeners, this method works great. However, not everyone sees success using Epsom salt in this way. The results can vary based on how much Epsom salt is used, the weather, and what pests are plaguing you. Flying insects, for example, will not be troubled by a line of Epsom salt.

If using salt doesn’t entice you, anything with a coarse texture can be substituted, such as coffee grounds, large grain sand, or small gravel rocks. These abrasive surfaces aren’t as potent to soft-bodied pests, but the course textures may dissuade them from a direct route to your plants.

Purple and white foxgloves in a garden
Sirintra Pumsopa/Shutterstock

Strengthening plants

Stronger, healthier plants are naturally more resistant to pests and disease, and can recover quickly. Epsom salt can provide an extra boost to your plants, giving them an edge over pests. You can mix a small amount into your soil; it only takes a light sprinkling for each plant. Be sure to work it into the top few inches of soil.

Epsom salt is a form of magnesium sulfate; a combination of magnesium and sulfur. Magnesium is a key nutrient for plants. It helps plants absorb other nutrients and develop chlorophyll, the green color in leaves that plants use to turn light into usable energy. If your soil is deficient in magnesium, Epsom salt is a great source. If your soil already has plenty of magnesium, it’s better to skip the Epsom salt. Too much magnesium can lead to a calcium deficiency and stunted growth in plants.

Killing pests

Epsom salt can also be used for killing pests outright not just repelling them. Dilute 2 tablespoons of Epsom salt per gallon of water, and fill a spray bottle with this solution. Spray it directly onto the pests.

The abrasive texture of the Epsom salt scratches the skin or exoskeleton of the insect. This leads to dehydration and death. It is a good pesticide if you want to avoid harsh chemicals and environmental impacts, but it isn’t the most effective pesticide since it only works when sprayed directly onto the pests.

A person with green and white gloves sprays a pest control solution from a yellow spray bottle onto some roses

Getting rid of weeds

Rising in popularity has been the use of Epsom salt as a weed killer. Recipes call for a mix of dish soap or liquid detergent, Epsom salt, and vinegar. At first glance, the mixture seems to work quite well, with leaves drying and dying rapidly. However, the effects don’t last long, and it’s easy to see why when considering the ingredients.

Epsom salt also improves plant growth; vinegar is acidic and will dry leaves out. If the weed’s roots run deep they won’t be affected by the vinegar and the plant will grow back. Dish soap helps the solution stick to plant leaves but otherwise doesn’t help or harm the plant.

If you have smaller weeds with shallow roots then a concoction of dish soap and vinegar may be helpful. Just remember that vinegar can also harm any other plants nearby. Don’t add any dish soap or detergent that contains bleach, either. Bleach and vinegar create a potentially lethal chlorine gas when mixed.

More flowers, more fruit

In addition to developing chlorophyll, magnesium helps strengthen your plants, potentially increasing the number and size of the flowers and fruits produced by the plant. If you’re looking to increase your harvest, you may want to target individual plants.

Dilute Epsom salt in water, roughly 2 tablespoons per gallon. You can water your plants with this instead of normal water once a month, or you can fill a spray bottle and gently mist your plants with it. Avoid misting plants that don’t like to get their leaves wet, like succulents, and you should see the benefits when your plants start blooming and producing fruit.

Epsom salt is good for more than just soothing baths: you can use it to strengthen and enhance your plants, increase your yield or blooms, and keep pests out of your garden. Although it doesn’t work as a weed killer, it has plenty of other good gardening uses. Remember not to overuse it – it only takes a little bit to achieve major benefits.

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