During the semi-annual gathering of the Belgian permaculture network Permanant, last March, we were offered a short training by Antoine Clin on slugs. A subject that fascinates Antoine so much that he devoted his PhD thesis to it. He talked to us about the role of slugs in nature, their life cycles, and strategies for coexisting with them. I’m sharing a few notes here, wishing you bountiful harvests in your garden.
Disclaimer: My note-taking wasn’t perfect! This article isn’t meant to explain everything about slugs and permaculture. Feel free to join one of our trainings to learn more!
Evolution
Slugs are essentially snails that have lost their shells — or most of them. Some species still retain a tiny vestige. This evolutionary change allows them to hide in the soil, which, in the end, gives them better protection against predators than a shell.
In Belgium, there are over 40 species of slugs, and most of them cause no damage. They inhabit many different microclimates (like forests) and play a vital role in ecological balance. What defines a “pest” species? Three criteria: their speed, their size (the bigger, the more they eat), and their reproduction rate.
Why Are Slugs Useful in Permaculture?
Often seen as pests, slugs actually play a key role in ecosystems — whether in the garden or the forest.
They actively contribute to the decomposition of organic matter. By “pre-chewing” it, they increase surface area, helping fungi, bacteria, and other organisms complete the nutrient recycling process. Slugs eat everything: plants, fungi, insects, dead animals… even other slugs!
On a plant level, slugs act as natural “cleaners”: they prefer weak or sick plants, helping limit the spread of diseases. This behavior supports natural selection — great in wild ecosystems, but not so ideal for our fragile salad transplants.
(Photo by Antoine Clin)
Slug mucus also contributes to the formation of the clay-humus complex, improving soil structure, aeration, and porosity — also thanks to the underground tunnels they create. This complex is essential to soil fertility. It’s a delicate bond between organic matter (humus) and minerals (clay). A wise old gardener once told me it’s “loving soil” — that beautiful crumbly texture every gardener dreams of. (A funny paradox: slugs and gardener’s dreams.)
They also help spread fungi — many of which are beneficial and essential to soil health.
Finally, slugs are a key food source for many animals: beetles, blackbirds, hedgehogs, foxes, wild boars, slow worms… They’re part of a healthy, balanced food chain.
Understanding the Life Cycle of Slugs to Garden Better in Permaculture
Slugs have a surprisingly fast life cycle, which explains their persistent presence in the garden. They are complete hermaphrodites: they only need to be fertilized once to lay eggs regularly — about every 10 days! In less than 30 days, a young slug can reach sexual maturity and quickly boost the population.
There are two main breeding periods: spring and autumn. Eggs and juveniles are frost-resistant, allowing them to survive the winter, even though reproduction pauses during cold seasons. Juveniles born in autumn can hibernate and resume development with the first signs of spring.
Personally, this was the key lesson from the training: it’s essential to act early in the season to prevent slug overpopulation later. Acting at the right time helps reduce their impact while disturbing the garden ecosystem as little as possible.
100% Natural Solutions to Integrate Slugs into a Permaculture Approach
Reinforce the presence of natural predators:
- Plant flowering borders and let tall grasses grow — this attracts rove beetles and ground beetles, both of which feed on slug eggs and adults.
- Install nesting boxes for blackbirds, or shelters for hedgehogs — both love slugs.
- Encourage landscape diversity: create micro-habitats, hiding spots for slow worms, and a wide variety of plants to boost natural garden resilience.
Let’s be honest: these solutions are rarely enough on their own in most climates.
According to Antoine, you can “distract” slugs using sacrificial plants like plantain or dandelion. Pick a few leaves 30 minutes before sunset and place them next to your seedlings. Slugs love them and will choose those instead.
Limiting Slugs in Permaculture: Common Methods to Adapt
Hand-picking remains a highly effective method. Since slugs are omnivores — and even cannibals — killing them with scissors and leaving them in place may be cruel… but it offers a gourmet meal to the survivors. If you’re vegan, you can collect them in a bucket and toss them over the neighbor’s fence.
You can also lay down white tarps or plastic sheets (white helps avoid overheating). Slugs will hide underneath during the day, making them easier to catch. These can also serve as shelters for slow worms, who love to eat slugs.
Beer traps work too, but they also kill other insects — including slug predators. If you use them, cover the containers with a lid to avoid rain dilution and refresh them regularly.
Chickens prefer small slugs and their eggs. Creating a “chicken moat” around the garden — a mesh tunnel connected to the main coop — can be very effective.
Indian Runner and Khaki Campbell ducks love slugs too. Letting them roam under supervision early in the season can be helpful. But beware: ducks don’t only eat slugs. Antoine recommends limiting their time in the garden.
Permaculture and Slug Management: What to Do When Natural Methods Aren’t Enough?
Ferric phosphate blocks slug digestion. It also acts as a fertilizer and is allowed in organic farming. It’s less harmful to non-target animals, but not completely safe. It’s very effective — and expensive. Many organic farmers use it as a practical solution.
Metaldehyde pellets are far more problematic. They harm non-target fauna (birds, pets…) and can pollute water. They dehydrate slugs rapidly. This product is not allowed in organic agriculture and should be avoided.
Bacillus thuringiensis (BT) is approved for organic farming and acts on various pests, like caterpillars or Colorado potato beetles. But it can also harm beneficial insects. It carries a real risk of collateral damage. For context: some GMO corn was engineered with a gene similar to BT.
Protecting Seedlings
Copper is often used to stop slugs from climbing onto seed tables (or young fruit trees). But slugs adapt. Several participants noted that it works for a while, but then becomes ineffective.
U-shaped aluminum profiles (like Metal Studs used in drywall) seem to be effective — slugs struggle to contort their bodies around the edges.
Conclusion
One thing is clear: this isn’t about winning a war against slugs — it’s about learning to live with them, while setting clear boundaries when needed. Permaculture invites us to observe, understand, and intervene wisely. From this mindset, frustration becomes curiosity, and sometimes… even admiration for these slimy little beings.
So before you grab the scissors or pellets, take a moment to look at your garden as a living ecosystem. Behind every chewed-up leaf might be a meaningful question — or even an opportunity to restore balance.
Thanks to Antoine Clin!