(Diatomaceous earth is also known as DE, diatomite, kieselguhr or kieselgur.)
When diatomaceous earth is dry, slugs and snails do not like to crawl over it.
But some do it anyway and when it gets wet, it loses its repelling effect completely.
Furthermore, it is an insecticide that affects bees and other beneficial insects.
Last but not least, it poses some health risks.
That is why there are much better alternatives to control slugs and snails naturally.
What is Diatomaceous Earth?
Diatomaceous earth (DE) is a sedimentary rock powder that consists of fossils.
Basically, it contains the shells of tiny diatoms, fossilized sea organisms that lived millions of years ago.
Chemically, DE is pure silicon dioxide (SiO2), which is non-toxic to humans.
The powder is abrasive because the broken shells have a lot of sharp edges.
One teaspoon of diatomaceous earth contains more than a billion tiny pieces of shell.
These pieces cut insects’ skin and absorb their moisture. That is why DE has a biocidal and insecticidal effect.
It is used as a natural pest control against all types of insects; for example, mites, cockroaches, and ants.
Does Diatomaceous Earth Kill/Repel Slugs and Snails?
Some people believe that DE might kill slugs and snails in the same way as it works against insects.
This is incorrect.
Slugs and snails are protected against the sharp edges by their mucus.
However, they do not like to crawl over DE, as the following experiment shows:
Video Test: Diatomaceous Earth Against Slugs
The beginning of the video demonstrates that some slugs crawl over DE without hesitation.
Most of the time, however, they prefer not to move over DE.
That is why many people recommend its use as a natural remedy against slugs.
How Should Diatomite Be Used Against Slugs and Snails?
Diatomaceous earth – food grade – is used to form protective circles around threatened plants and beds.
After rain, irrigation or other forms of moisture, the protective ring must be renewed.
During application, you should wear gloves, respiratory protection and goggles to prevent health risks.
This is because diatomite, inhaled as dust, can lead to respiratory diseases and can even be carcinogenic.
In case of eye contact, flush your eyes out thoroughly and consult a doctor.
Also, to protect children, it is important to store diatomaceous earth in places that are always inaccessible for them.
In most states, it is forbidden to dispose of diatomaceous earth in the sewer. Instead, you should take it to a recycling center.
Products and prices
Diatomaceous earth is available in different varieties.
The type also depends on the region where it is mined. Every area produces a different mixture of diatoms and shell forms. Some are sharper than others.
In addition, preparation and intended use differ.
Never use ‘pool filter grade’ DE as it carries particularly harmful health risks if you inhale it! It might also harm plants.
Therefore, only use ‘food grade’ or ‘garden grade’ DE.
The costs of DE depend on the amount needed and on the manufacturer.
It is not cheap: Find prices and more information on Amazon.
Normally, it is used in animal husbandry.
Diatomaceous earth is a suitable agent against mites and other vermin in animal husbandry.
It is not recommended in the fight against slugs and snails.
Not only is it expensive and impractical, but its efficacy in repelling slugs is also questionable.
The significant disadvantage is that diatomite is no longer effective when moist because in wet conditions slugs are particularly active.
Unfortunately, the insecticidal effect of DE can also kill valuable natural enemies of slugs and snails.
For example, it kills ground beetles, soft beetles, fireflies, and other insects that help in the fight against slugs and snails.
In addition, it is unsuitable for large areas.
The price is high, and the application labor-intensive as protective walls made of DE must be renewed after rain.
Finally, there are health risks that make application more difficult and dangerous.
In a household with children or pets, the product is therefore not recommended.
There are safer, cheaper methods and ways to protect plants against slugs.
What Are Alternatives to DE?
There is a wide range of alternative methods.
To protect individual plants, special snail and slug collars are recommended.
They are weatherproof and harmless to animal and human health.
For larger beds, slug fences are an effective alternative. They are safe and provide long-term protection.
Planters and pots can be protected, for example, by protective stripes of slug-repelling copper tape.
It is also possible to use the slug-repelling paint, Schnexagon.
In addition, it is possible to cultivate slug-resistant vegetables and herbs.
There is also a long list of flowers that slugs do not like to eat.
Long-term slug control focuses on attracting natural enemies of slugs and snails.
Here, you will find an overview of measures to control slugs and snails.