Are Slugs Bad For Gardens

A number of years ago I started a forest garden in the middle of a very wet woodland, in the midst of a slug stronghold – I could easily collect a large jarful of them at dusk. But after an intensive research and learning process with many failures, I now only need go out once a week or so to gather up slugs, and even then I only find a few. There are many tips about how to fight these invertebrates circuiting around allotments and gardens – some are fables, some are more effective than others. No single thing does the trick. The solution is to create an ecosystem in your garden to help to create a balance. It sounds easier than it is, but it greatly increases the joy gained from your garden, and once established it looks after itself.

1. Know your enemy

There are many different kinds of slugs and some are more harmful than others. The large black slug doesn't do much damage at all as they prefer rotting matter, dung and carrion over living plants. The garden slug is the opposite, attacking anything that even slightly resembles an herbaceous plant.

2. Introduce and encourage predators

Slow worms: These beautiful creatures are becoming rare and are strictly protected, so it is not a good idea to pick them in the wild. The only way to get them in your garden is to provide a good shelter and hope they turn up. A sheet of corrugated iron or black plastic in a slightly raised and sunny spot near the compost heap seems best. If you have them, protect them well – they are a great ally!

Hedgehogs: There is an issue whether it is ethically justified to keep hedgehogs in the perimeter of an allotment or garden but if the hedgehog has a habitat able to provide it with all the essentials it needs, I think it is. I received hedgehogs from the Hessilhead Wildlife Rescue Trust and introduced them into my garden. It is not a straightforward process as they need to inspect your garden to determine whether it is safe for hedgehogs – a road or badgers nearby would give you a negative reply. But if you are lucky enough to have a hedgehog, a hag pile and some decent fencing to stop it going on the road is important as protection. Make sure there is enough food for it in the garden but don't leave out milk, or cat food (attracts vermin), and don't de-flea it as this would kill it.

Live Better: Natural slug control — Hedgehogs are a gardener's friend, as they eat snails, slugs and insects. Photograph: Tim Melling/Getty Images/Flickr RF Photograph: Tim Melling/Getty Images/Flickr RF

Ducks: Experts recommend Khaki Campbells or Indian Runners who are the best carnivores – other breeds might eat more of your vegetables. A good permaculture solution would be to have your garden in between the duck hut and the pen, thereby allowing the ducks a good munch in the morning and evening while on the way to and from home.

Beetles: Carob beetles are very effective slug predators – the larvae and beetles eat the eggs and the tiny slugs. If you have these beetles in your garden, you can help by providing a good home for them; some patches between your beds with tough grasses or sedges, straw or hay in an upside down plastic box, stones to live under and well drained soil are all good.

Centipedes: These are carnivorous nocturnal hunters. Learn to distinguish between the millipedes and centipedes, as millipedes are herbivores and love young seedlings. The centipedes I know are harmless. Centipedes like it moist so live in leaf litter, under stones, in rotting wood etc.

3. Control by distraction

There are plants out there that slugs like better than your vegetables. If you grow them in your garden they will attract the slugs and all you will need to do is pick them up at dusk or put a slug trap nearby. Lawn Camomile is my favourite because it is most effective in spring when my seedlings are small and most vulnerable. It is a perennial, so when the annuals are at the most vulnerable, the camomile is in full swing already. You should also rub the plant as the scent released attracts slugs.

4. Control by death or relocation

I used to catch slugs in a jar and relocation them until I realised that, in essence, I was transporting an imbalance from one ecosystem to another. Now I kill them without mercy, but as humanely as possible. The most effective way of finding them is to go out with a torch just after dusk or on a miserable grey wet day. Make sure to look on the underside of the vegetable leaves and let the plant damage and slime trails guide you.

Jars: Drown slugs by putting them in a jar filled completely with water and keeping the lid screwed on tightly. A bucket with water is not good enough, the slugs will just crawl out again.

Sharp knife: My preferred method at the moment is a sharp knife. I use it flick the slugs of the plant onto the soil surface and behead the poor things. I think it is the quickest death, and the most convenient.

Beer traps: After trying several designs this is the winner. The slugs are attracted by the fermentation gasses of beer. Any cheap lager or homebrew is good, though ales and Guinness are best. Place the traps at the edge of the beds. If you place them in the middle, slugs might get distracted by your juicy vegetables on the way to the pub.

Other traps: Grapefruit halves, flower pots, cardboard, or anything dark and moist will be favoured by the slugs as a hiding place during the day. Inspect and capture at your leisure.

I feed some slugs to my frog spawn – they even fight for them – and I hope it helps them to develop a taste for slugs when they are older.

5. Border control

Copper: Slugs don't like to crawl over copper. A dozen or so pennies stuck into the soil around a seedling can form a border – a stripped electrical cable is even better. Cut the top and the bottom of a plastic bottle. Wrap the stripped cable a few times around it with one or two loops in it, fasten it to the bottle with duct tape through the loops and flatten the copper loops to the plastic. Dig the plastic into the soil so that slugs don't crawl underneath. If you use sticks to support the plant, wrap copper around the sticks too. Make sure none of the leaves touch the ground or any weeds touch the plant. Slugs can't fly but they know how to find shortcuts.

Egg shells: The sharp edges of eggshells help as a deterrent, but only when they are clean and dry. When peeling an egg, try to remove the inner membrane and rinse if needed. Be aware that rain quickly makes the eggshells lose their effectiveness.

Do not try:

Salt: Pouring salt around your veg will keep the slugs away indeed, but unless your plants like maritime conditions they will die too!

Seashells: The sharp edges deter slugs from crossing, but they don't decay like eggshells and can be a serious nuisance when weeding for many years to come.

Slug pellets: Most are not organic and will kill the predators too. Even the organic ones are not wise to use: when the slugs die, the predators leave to find food elsewhere – leaving you dependent on the pellets.

Ludwig Appeltans is a permaculture designer and teacher.

This article originally appeared on permaculture.co.uk and has been republished with permission.

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