Wood Ash to Deter Slugs and Snails in the Garden | Does It Work?

The Theory: Ash Should Repel Slugs and Snails

The drier it is underground, the harder it becomes for slugs and snails to move around.

So, dusting the soil with ash should mean it becomes less attractive for slugs to cross.

Moving on the ash makes slugs and snails lose fluid and slime, so they find it difficult to creep along.

That is why ash should repel even resilient Spanish slugs.

If you have a fireplace or stove, you probably have more than enough ash available.

Ash can be stored easily during the winter months and used during the garden season to fend off slugs and snails.

However, is it worth the trouble?

Practical Test: Does Ash Work as a Slug Repellent?

Whether ash works or not is subject to a lot of discussion.

There are as many critical voices as there are advocates.

So, I decided to investigate and conducted a little experiment to test the repelling effect of ash.

You can see the results in the following time-lapse recording.

Video: Ash Against Slugs Test

The experiment showed that both sides are right: ash works to repel some, but not all, slugs and snails.

Tiny slugs and snails especially are deterred efficiently.

Snails and leopard slugs, in particular, turn around immediately after coming into contact with the wall of ash.

Unfortunately, bigger slugs, such as the Spanish slug, are not that easy to stop.

Although the ash was extremely dry, some intruders tried to secrete slime, so they could cross over it.

So, it became clear that although ash does work as a repellent, it cannot provide complete security.

That is why you could combine ash with other means such as mechanical slug barriers.

How to Use Ash

Scatter dry ash around threatened plants and beds to form a protective wall.

The wall should not have any gaps and should be as wide and thick as possible.

The more ash you use, the greater protection there will be.

After rain or irrigation, be sure to renew the barrier because moist and damp ash loses its deterring effect.

Also remove any bridges that might help slugs to bypass the wall.

Advantages

One significant advantage is that ash is available for free to all gardeners who own a fireplace.

It also acts as a fertilizer and benefits the soil as it contains potassium and other vital minerals and micro-nutrients.

Finally, the presence of ash means that composting of other substances is supported and accelerated.

Disadvantages

Ensure that you use only ash from untreated wood, otherwise toxic substances may contaminate first the ash and then the ground.

Ash from old trees can contain heavy metals that should not end up in a vegetable garden, as the toxins could otherwise pass into food.

In flower beds, the use of ash might not cause a problem.

Unfortunately, after a little rain, any protection from ash is lost.

So, be sure to check and renew the ash regularly.

Gusts of wind can also quickly carry away dry ash and create gaps in the barrier.

One significant disadvantage is that the lime content will raise the PH value of the soil and not all flowers and plants appreciate that (e.g. pepper).

So, you should pay close attention to see which plants tolerate ash and which react badly to it.

In addition, some people find ash on flower beds unsightly.

Conclusion

The good news is that ash has a repelling effect and tiny slugs and snails are already deterred by a few centimeters of ash-ground.

The significant weakness of this method is that it is not waterproof and therefore requires maintenance.

When it is raining, and slugs and snails are very active, ash does not work to protect the plants.

However, ash is also beneficial as a fertilizer.

If you know which plants tolerate ash and which do not, the application is easy.

However, it is crucial to use only ash from untreated wood, because no one wants to have heavy metals in the garden and therefore in food.

Heavy metals can become highly toxic.

Alternative Slug and Snail Barriers

Mechanical barriers are good alternatives to barriers formed by mulch materials.

They are also painlessly efficient and require no further work once constructed.

Slug fences are not cheap, but they are durable, suitable for protecting large beds, and need no maintenance.

They provide a long-term solution and are less labor-intensive than ash and most other methods.

You will find more information here:

Slug fence test	Slug barriers

To protect individual plants, special slug collars can be used.

Also, garden cloches can protect seedlings and young plants.

Furthermore, the anti-slug paint Schnexagon will keep slugs out of beds and greenhouses.

This repelling coating sticks to almost all materials and can be painted on quickly and easily.

Finally, there are other materials that work in a similar way to ash as a deterrent due to their dryness or saltiness.

One possibility, for example, is to use salty sheep wool against snails.

You will find more information here: mulch materials against slugs

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Slug control recommendations

Copper Mesh Fence	Slug Fence Set: Medium – 6m²	Sheep Wool Pellets
Check prices on Amazon	Check prices on Amazon (Europe)	Check prices on Amazon

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Last update: July 18, 2019

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