What methods are available? Which are worth trying?
Creativity and inventiveness seem almost inexhaustible when it comes to warding off slugs and snails.
Some recommended counter-measures are for example:
Coffee
Salt
Eggshells
Ash
Sheep’s wool
Liverwort extract
Rock flour.
And increasing snail and slug infestations have fired the inventive spirit.
New methods to ward off slugs?
Some other ideas include:
Snail fences
Copper tape
Snail & slug collars
Slug-repelling paint etc…
A total of 23 methods are compiled in this list.
Unfortunately, not all of them hold what they promise.
Slug-control ideas and what they really do
Ash against slugs?
Ash
Effectiveness: little to useless
If the ashes are bone dry, they may repel small slugs and snails. But once it rains, it loses all effectiveness. Larger snails and slugs also cannot be repelled by ash.
Side effects: positive to dangerous
Generally, ash is a useful fertilizer which is rich in minerals. But unfortunately, it is often also contaminated with heavy metals, which do not belong in a vegetable garden.
Beer traps only lure more slugs into the garden. Due to the strong attraction through yeast, the only person benefitting from this method will be your neighbor, whose garden will suddenly be snail-free.
Side effects: dire
Slugs natural enemies also suffer from these traps. Ground beetles perish in them and hedgehogs can get poisoned from the alcohol.
We concluded an experiment, which showed a minimal repelling effect the eggshells had. A small effect was noticeable, especially on snails. Larger slugs, however, won’t be repelled.
Side effects: positive
Eggshells are full of nutrients and therefore greatly aid the soil and the growth of plants.
This experiment was really convincing. All slugs and snails were repelled successfully. But after the first rainfall, all protection was gone. This method can be used in places protected from rain.
Side effects: positive
Sheep’s wool is a natural carbon fertilizer. What’s more, wool also often contains feces, which benefits the soil even more.
Very dry coffee grounds have a repelling effect, which is only down to the dryness. Inconclusive yet is the question, how well a coffee concentrate spray works.
Side effects: positive
Coffee too is rich in nutrients, and earthworms love coffee grounds. Therefore, they are always welcome and helpful in flowerbeds.
Available are quicklime, slack lime and nitrolime. The effectiveness is questionable, as rain is once more a spoilsport. Nitrolime appears to be effective, but is harmful to your health, to your plants and the health of animals.
Side effects: positive to dangerous
Garden lime is useful if a soil is too acidic. At the same time, too much lime leads to a high pH-level, which many plants dislike.
I have not yet managed to test diatomite, but it doesn’t seem to be a miracle remedy. As it is very dry, its effect will probably abate once it starts to rain.
Side effects: dubious to dangerous
This material can harm the lungs. Furthermore, it is a strong insecticide and thus harmful to the main natural enemies of slugs and snails: Which insects eat slugs?
Effectiveness: works against some slugs, not Spanish slugs
Since the nematodes live in the soil, they only infest slugs that live partly underground. Many slugs and snails do not do that, e.g., the Spanish slug.
Side effects: dubious to dangerous
Nematodes can be dangerous for people with weak immune systems. We therefore advise against using these parasites. There are less dangerous means of repelling slugs and snails.
These protective covers don’t only protect from frost, but also from slugs and snails. Plant hats and garden cloches can also be combined with other slug and snail barriers.
Side effects: positive
They offer optimal growing conditions and protect young and small plants from many dangers.
The test we carried out showed that although a few snails were deterred, others immediately hid inside. Rain will probably also completely destroy the deterrent.
Side effects: positive to dubious
In itself, it is a good idea to mulch with sawdust or wood shavings. However, if too much is used, the ratio of nutrients in the soil can shift unfavorably.
Scattering salt in the garden is forbidden by law and also really not a good idea.
Side effects: questionable to dangerous
Salt over acidifies the soil and makes it infertile. The living organisms in the soil and also the plants suffer from acidic soil and eventually die off.
Live traps for slugs and snails are an effective way to reduce their population. You can be tricky and create specific places where the animals hide during the day. Then collecting them is easy.
Slug pellets help in the short term, but in the long term they stand in the way of successful slug control. This is because slug pellets harm the slugs’ enemies and prevent biological equilibrium from being established.
Side effects: poisonous to deadly
In addition, useful snails are also killed, such as leopard slugs, which are also among the enemies of the Spanish slug. In addition, the pellets are dangerous for pets and even humans, which can be fatal. Iron phosphate is also particularly problematic, as the snails do not die immediately here, they still have plenty of time to multiply beforehand.
Electric slug fences work well as long as they are powered with sufficient electricity. But there is always the danger of a power outage.
Side effects: none to maybe
As a rule, no side effects are to be expected. But electricity always means a small fire hazard. More on this here: Electric snail / slug fence.
Mechanical slug and snail fences
Effectiveness: excellent
These fences are effective and perhaps one of the safest ways to protect plants. Their special edge keeps slugs out of garden and flowerbeds. Since we wanted to be sure before recommending these fences, we did some testing.
The protective coating works well against slugs. But it is not weatherproof indefinitely. After a certain period of time – depending on the weather – it has to be reapplied.
The experiment indicated a slightly deterrent effect. But large slugs and snails were hardly impressed. Here, too, rain or irrigation will cancel the effect.
Side effects: positive
The rock flour contains trace elements and minerals. Therefore, it is useful for plant health and growth.
Land snails cannot breathe underwater. Therefore, sufficiently deep and wide water obstacles are usually insurmountable for them. Our test indicated that slugs in particular have a problem with water – keelback slugs less so.
Side effects: positive
A positive side effect is that other animals, e.g., birds, hedgehogs or beneficial insects, can use the barriers as a source of water.
