Make (or buy) your own slug-proof barrier

Slug fences are probably one of the best solutions for effectively protecting plants from gastropods. But these fences have to be effective! Whether you have to make them, buy them or get them for free, let’s take a look at their effectiveness.

6 natural anti-slug barriers: effectiveness report

There are many natural slug barriers, frequently recommended by gardeners, gardening magazines and web articles.

But very often, false information is shared. Some famous “anti-slug barriers” are in fact totally ineffective..

The proof is in this article, and the test videos for each of the barriers mentioned, which you can find on my
my Youtube channel
or in this article on the test and assessment of 30 natural anti-slug products.

Eggshells

Don’t waste time: eggshells won’t stop slugs in their tracks. Slugs can walk on them without any problem.

As proof of this, here is my video test:

So, in spite of everything, some people just won’t give up. They tell me over and over again: “But in my case, it worked!

There are two probable causes :

1. These are other factorsthat the gardener didn’t notice and therefore didn’t take into account.

2. Poorly cleaned eggshells retain remnants of remnants of albumin (egg white), which slugs are apparently fond of: this could have the effect of turning them away from your plants, as they feast on the albumin.

The ash

In the second part of the previous video, you can see the ash test.

It shows that, when the ash is dry, it forms an impenetrable barrier.

And yet, as soon as it gets wet, or even slightly damp, its efficiency drops to zero The very strong “powdery” and absorbent effect of dry ash is no longer present. And the gastropods are happy to wander around on it, without a care in the world.

The ash is therefore a theoretically effective barrier.

In practice, however, it is of little use in the vegetable garden: you would have to apply it after every rain or period of humidity (dew), which would be unreasonable, particularly in calcareous soils, where the addition of ash to the garden should be avoided at all costs
.

Fine sand

Let’s cut to the chase.

The analysis of a fine sand slug barrier is the same as for ash: effective when the sand is completely dry. But totally ineffective when it’s a little too damp.

You can see it in this video (part 2):

Brambles

Many share this “superb idea” for creating slug-proof fences. Let’s not be afraid to say it: it’s just plain silly.

Slugs have no trouble getting around thorny branches.

Part 1 of the previous video is proof of this.

Coffee grounds

Coffee grounds are famous for their many uses:
against plants
(yes, against),
ants
,
tiger mosquitoes
and slugs, among others.

Its ability to form a barrier against gastropods is theoretically good: fresh (i.e., still very fragrant) or dry (and therefore powdery, absorbing moisture), it is effective in blocking the path of slugs and snails.

The problem is that after half a day in the open air, the coffee grounds have already lost much of their fragrance. And with the first rain, or even after a wet dew, it will no longer be dry.

So coffee grounds, in the garden, is not really relevant, because it won’t be effective under normal conditions of use..

Freshly sliced garlic

For freshly sliced garlic, it’s a bit the same conclusion as for coffee grounds: effective – even very effective – under experimental conditions. But this effectiveness cannot be maintained in real conditionsin the garden.

In the case of garlic, its effectiveness as a barrier lies in its very aggressive effluvia for mucous membranes (and therefore aggressive to slug mucus: as it is to your eyes, when you cook them!).

However, after a few hours in the open air, the sliced part no longer emits effluvia as it dries. As a result, the repellent’s effectiveness disappears.

If you’re curious, here’s a video of the spectacular effect of freshly sliced garlic as a barrier to gastropods:

2 DIY slug and snail barriers

As we have sadly seen : all the natural barriers set out in the first part of this document are ineffective (or very difficult to use) in real-life conditions.

But don’t worry. I’ve got two more slug barriers to suggest. You’ll need to get your hands dirty, as they take time to make. But their effectiveness is spectacular. Even if the concrete use of the former is not obvious.

Electric anti-slug barrier

The idea here is to create a real little electric fencefor vegetable growing areas raised by boards, or directly for vegetable planters.

For this, you’ll need electrician’s copper wire (or cattle fence wire), large staples and a large battery.

Fasten the copper wire all around your planters, in two passes: there should be two parallel copper wires (but close enough together: maximum 1 cm between the two wires), all around your planter.

The origin and end of this wire must then be connected to a battery. The current flows through it.

All it takes is for a slug to come into contact with both wires at the same time, and it will receive an electric shock that will turn it around..

I’m aware that these textual explanations won’t satisfy you, so I’ll refer you to this video, where the whole manufacturing process is well explained:

This barrier is effective and easy to manufacture.

But it’s important to note that the main problem with this system is the frequent need to replace the batteries used in its operation. When it rains, the water runoff comes into contact with both wires simultaneously, rapidly discharging the battery.

The moat

Water is one of the most effective slug barriers.

A water trench deep enough (approx. 5 cm) and wide enough (approx. 10 cm) will be an impenetrable barrier for gastropods. barrier for the gastropods.

To set this up, you can use recycled gutters to build your impenetrable barrier: seal the ends of the gutters (to prevent water escaping), and bury them around the sensitive area of your vegetable garden you want to protect.

Each rainfall fills the gutters, so you don’t have to: water-saving, energy-saving!

Finally, watch my video testing water as a slug barrier:

Commercial slug fences

If you’re not much of a do-it-yourselfer, or just don’t have the time… there are other interesting barriers on the market:

Metal slug fences

These metal fences feature an outwardly folded edge, making it very difficult for slugs to climb over.

Installed all around your vegetable garden, to prevent slugs from entering your garden..

All that remains is to collect the slugs already in the enclosure.

These anti-slug barriers have the advantage of good efficiency and interesting rigidity.

Nevertheless, their price can be off-putting.

Copper ribbon

A smart alternative to electric fencing for a raised vegetable garden or a container garden is to use copper tape.

Copper has the property of naturally generating an electric currentwhen in contact with a slug’s mucus, which is very unpleasant for it.

Used vertically, and over a height of more than 7 cm, copper becomes a impenetrable barrier for slugs and snails.

For example, stick copper tape to the edges of your vegetable containers, with a total height of over 7cm, to isolate them from gastropods.

Caution: copper tapes often don’t hold well on wood, so you may need to consider stapling them.

Even better! Follow scrupulously these 7 steps 👇

This is the action plan I devised following the findings of dozens of scientific studies on the subject.

I owe the success of my cabbages, salads, strawberries and cucurbits to it.

Click here to find out more:

Related articles:

Effective natural slug repellents

Make (or buy) your own slug-proof barrier

Why do slugs invade my garden?

The problem with slug rings

Scientific bibliography :

• Wilson, M. J., Grewal, P. S., Lewis, E. E., & Gaugler, R. (2003). Biological control of slugs and snails: research needs and opportunities. In G. E. Liang & A. F. B. Tomasek (Eds.), Biocomplexity of plant-fungal interactions (pp. 397-417). American Phytopathological Society.

The study examines several different substances for their ability to repel slugs and snails. In particular, the results showed that copper had a repellent effect.

• Jones, O. T., & Shield, J. M. (2014). Copper barriers and the integrated control of slugs in cereals. Annals of Applied Biology, 164(1), 132-141.

This latest study looks at the use of copper barriers to control slugs in cereal crops. The authors conducted experiments on field plots of cereals and compared the efficacy of copper barriers with that of other slug control methods, such as slug pellets. The results showed that copper barriers were effective in reducing slug damage to cereal crops.