Epsom Salt Lawn Tonic: big boosts for a small cost

Though it may not seem like it right now, spring is just around the corner. And homeowners everywhere will be looking for a tried-and-true method for a greener, healthier lawn – fast. Epsom salt lawn tonic is a well-known home remedy – used for soaking sore and tired muscles, or exfoliating away dry skin, and many gardeners believe it will also work wonders outdoors.

What is Epsom salt?

Named for the area where it was first mined in 16th century England, Epsom salt is the common name for magnesium sulfate. Though their crystalline structure resembles table salt, they are in fact very different chemicals.

How can Epsom salt help in the garden?

Magnesium sulfate can be used to increase either the magnesium or the sulfur content in the soil. Therefore, it is frequently used by horticulturists. Certain plants require soil that is rich in these minerals, and Epsom salt can be used in many ways to boost soil quality.

Some claim that Epsom salt with result in bigger and showier blooms, thicker and more robust shrubs, as well as thick and vibrant green lawns. It’s also been recommended for controlling garden pests such as insects and rodents.

Is Epsom Salt use backed by science or just an urban myth?

Commercial agriculture

Many commercial growers use Epsom salt in areas that are intensely cultivated where the soil has shown, after testing, to be deficient in magnesium. But in the typical home garden, unless the soil is very sandy with large amounts of rainfall, there are usually sufficient levels of both sulfur and magnesium to support healthy plant growth.

Epsom salt to speed up seed germination

Many articles explain that magnesium strengthens cell walls, and provides increased energy for seed germination and growth. 

Scientifically speaking, a seed has all that it needs to germinate and doesn’t require any fertilizer to do so.

Seeds started in quality potting soil under the proper heat and moisture conditions should grow well on their own.

Epsom salt as a fertilizer

Several online articles and blog posts promote adding Epsom salt to the soil when planting, or adding it to a pre-mixed fertilizer.

However, most commercial fertilizers have been specially calibrated to provide optimal amounts of nitrogen, potassium, phosphorus, magnesium, calcium, sulfur, and other elements.

Anything not used by the growing plants is washed into the groundwater, perhaps eventually to find its way into streams and rivers, or the drinking water system.

In some cases, what the home gardener perceives as a lack of sulfur or magnesium –faded blooms, and sparse or lackluster produce yield – is actually due to an overabundance of another mineral in the soil.

Therefore, adding Epsom salt won’t improve the situation – in fact, both magnesium and sulfur are micronutrients, and plants need only a small amount of each for healthy growth.

Epsom salt to make your lawn greener

Epsom salt can help to prevent a yellow lawn, and may result in lusher, softer, greener grass; the minerals found in Epsom salt are quite beneficial for green plants.

Magnesium and sulfur are important to the photosynthesis process, and to the production of chlorophyll.

They may also help to improve the absorption of other important minerals such as phosphorus and nitrogen.

However, no scientific evidence is available to suggest that grass requires magnesium – and, as it is highly soluble, half of the application will likely be washed away by the next rainfall or watering.

If you decide to add magnesium sulfate to your lawn, there are two options for application: dry Epsom salt can be spread directly onto a damp lawn, or it can be diluted and then sprayed onto the grass.

The recommended dose is three pounds per 1250 square feet of lawn.

Epsom salt as a pesticide

It has been claimed that Epsom salt is an effective treatment against many garden pests: weeds, insects, and tunneling rodents.

A mixture of dish soap, Epsom salt, and vinegar has been recommended for killing weeds. This “miracle cure” for weeds has gone viral many times over – and with reason: the dish soap helps the mixture stick to the plant and spread slowly along the leaves, while vinegar will dry out the plant.

epsom salt lawn tonic has kept weeds out of this grass
Applying Epsom salt helps to keep weeds out of this grass.

But, as Epsom salt has been touted as an excellent fertilizer, it doesn’t make sense to then add it to a weed killer. It is ordinary table salt that can prevent plant growth.

Furthermore, this miracle mixture may only work on small weeds – larger plants with taproots such as dandelions will likely bounce back after the initial damage.

Rather than using table salt to dehydrate snails and slugs, which can also harm the plants in your garden, using Epsom salt will eliminate these pests as it can scratch and irritate their bodies which deters them from crossing an Epsom salt barrier, and – as an added bonus – it gives a boost to the plant, enriching the roots and blooms.

Magnesium sulfate crystals can also be used to prevent groundhogs from raiding a vegetable garden. Epsom salt has a nasty taste, which means that sprinkling it on the plants will deter any four-legged food thieves.

Sprinkling salt around the perimeter of the garden will create a barrier, keeping any curious groundhogs out of the garden; it can also be spread around garbage cans or near shrubs, or even around the entrance to the burrow.

Is it worthwhile to use Epsom salt in the garden?

While there is little scientific evidence that Epsom salt is truly a miracle fertilizer, pesticide, and garden cure-all, there is likewise little indication that adding magnesium sulfate to your garden will cause irreparable harm.

For years, gardeners swore by home remedies, which were gradually replaced by more commercial – and often more chemical – solutions. For those who wish to maintain an organic garden, Epsom salt can be a very useful tool.

It’s a pH-neutral product that will dissolve easily into magnesium and sulfur, which are beneficial in some way to most plants. Epsom salt is non-toxic and most preparations are safe for human consumption.

Further, they are inexpensive and anecdotal evidence suggests that they do have many uses around the house – both indoors and out.