Types of Slug Barrier

In contrast to the all out annihilation of the trapping and killing methods I told you about elsewhere, another approach to dealing with the menace of slugs in the garden is to create barriers.

Dish of crushed egg shells

That old favourite – crushed egg-shells

This is more of a passive, defensive tactic; keeping a little more distance between the slug and your precious plants, with the hope that the two can maybe live in harmony.

Types of slug barrier

Slug barriers – like most things when dealing with slugs – can take on many different and ingenious shapes and forms. They do however, fall into two main categories:

Physical barriers

Something the slug cannot cross, ranging from protecting a single plant with a plastic bottle to encompassing a whole section of garden with a copper strip.

Nuisance barriers

The sort of thing the slug could cross but prefers not to because it’s unpleasant and uncomfortable. An excessive amount of mucus, or slime, is required to traverse it, and this isn’t good for the slug.

The second of these can also fall broadly into two categories:

Rough scratchy surfaces

Something like grit, or the old favourite, crushed egg shells, that are painful and difficult to cross.

Desiccating surfaces

Things like ash, sawdust, or diatomaceous earth that dehydrate and dry out the slug.

Of course, some materials – like ash or diatomaceous earth – are both rough and possess desiccating properties. Others – such as a barrier of entangled fur or hair – don’t fit neatly into any single category.

Remember that the slug’s slime is ‘hygroscopic’, meaning it absorbs moisture. So in wet weather the slime is much more effective, allowing the slug to tackle most rough surfaces with apparent ease.

Did you know...

A slug’s slime enables it to glide without difficulty over glass shards, or even the edge of a razor blade.


A relatively new type of slug barrier comes in the form of copper. The slug’s slime causes a chemical reaction that creates a small electric current, and the slug hates the resulting mild electric shock...  Ouch!

Many new copper based deterrents are now available, including:

Copper tape

Self adhesive copper tape to stick around your pots and containers, or to create a slug barrier around just about anything. As well as keeping slugs at bay, I think the copper tape adds a touch of ‘class’ to an otherwise ordinary container.

Copper rings

Slip the copper ring around single or small groups of plants. Available in various sizes, these rings clip together so you can easily fit them around established plant stems. This also allows you to join them together to form a larger barrier.

Copper feet

This is a clever idea; copper feet to support your pots and containers. Not only do they look attractive and stop slugs from reaching the plants inside, they ensure good ventilation and drainage for your containers too.

Helpful tip

With all barrier methods, thoroughly check the area to be protected for any slugs and snails first. The idea is to keep them out; not trap them inside!

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Did you

Like sharks, slugs routinely lose and replace their teeth

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