Slugs and snails can be a major pest in some gardens and though a domestic polytunnel can help you to control the pests somewhat, some are bound to slip through. If you discover that you have a bit of a slug problem in your polytunnel never fear – there is plenty that you can do to return the natural balance and get rid of slugs to keep slug numbers in bounds.
Attracting Predators to Get Rid of Slugs
Far and away the best thing to do to keep pests in check is to do what you can to keep nature’s balance intact. When the balance is intact, slugs and snails tend to remain in small numbers only, making any problems small ones. There may always be a few slugs in your garden, but having a few is not usually a massive problem. Problems really only arise when there are so many slugs and snails that you end up losing a number of valuable plants or a good portion of the crops you are trying to grow in your garden or polytunnel.
To make sure the balance in your garden is established and maintained, gardener’s must do what they can to garden organically. Attracting and protecting predatory wildlife will help to keep slug and snail problems at bay.
One of the best things gardeners can do to attract and care for birds is to make sure they have enough food throughout the year. Gardeners should choose a variety of feeders to beautify their gardens and care for specific native species. Planting a range of berry bushes, grasses and other plants to feed the birds can also be part of the picture.
Keeping wilder areas of shrubs and hedges in your garden will help to encourage birds and will give them plenty of places to shelter from the worst of the winter weather. Nesting boxes can also help birds like song thrushes them make their home nearby, ready to munch problem pests such as slugs and snails.
Birds will also need to drink and bathe. If you are short on space, you can buy or make a small bird bath. But to improve the biodiversity in your garden, a pond could also be a good idea.
Attracting Frogs & Toads
A garden pond will be a boon to a wide range of wildlife in your garden. Creating a natural garden pond in your garden will also attract creatures like frogs, toads and newts, all of which can naturally help to keep slug and snail numbers down.
By also creating nearby habitat for toads to hide in when they are not in the pond, you can help make sure that these useful predators stay in and around your garden throughout the year. Taking care when mowing your lawns or tending your garden near the pond, you can help to keep these creatures safe.
Hedgehogs are now sadly endangered, but attracting these creatures is not only a way to help save this cute and attractive species, it can also help you control the numbers of slugs and snails in your garden. Create entrances between your own garden and those of your neighbours to allow hedgehogs to pass through. Make sure that you leave wilder corners and create spaces for hedgehogs to hibernate undisturbed in your garden. You can also entice hedgehogs to your garden by leaving out water and creating a feeding station.
Attracting Other Slug Predators
There are some other creatures that are useful predators of slugs and snails. For example, slow worms and other reptiles can be attracted to your garden by creating compost heaps and warm spots for them to bask on or under. Ground beetles, centipedes, and other insects also predate slugs and could be encouraged as part of a natural way to get rid of slugs.
Keeping Chickens or Ducks to Get Rid of Slugs
One final way to combat a slug problem through predation is to begin keeping chickens or ducks. These creatures also eat slugs and help to keep them away from your precious crops. Just don’t leave them unattended around your leafy greens – chickens will often eat everything in site, and scratch up the ground, while ducks can quickly turn a vegetable patch into a muddy mess if you are not careful.
Natural Slug Repellents
Once you have done what you can to restore the natural balance and keep slug numbers down through natural predation, you may still find that you have certain problem areas in your garden or polytunnel. But even where you still have a slug problem after doing what you can to attract their predators, you still do not have to resort to slug pellets or other inorganic, polluting methods to control the problem. You can consider protecting individual beds or plants by:
- Using cloches or mini polytunnels to protect tender seedlings.
- Surrounding beds or plants with copper tape or pennies. (The copper gives slugs a small electric shock that keeps them away. Note, however, that you will have to wash the tape or pennies in vinegar regularly to retain its efficacy as a barrier.)
- Placing coffee grounds around susceptible plants.(Ground coffee beans, not instant coffee. The higher the caffeine content, the more slugs will dislike it and stay away.)
- Placing sharp egg shells around certain plants. (Slugs to do not like to cross sharp things like egg shells or broken nut shells. Wood ash, lava rock, charcoal and other barriers are also said to work in a similar way to get rid of slugs.)
- Placing sheep’s wool around plants in threat.
- Placing seaweed around beds or plants. (The salt content can help keep slugs away, while the seaweed will also add a range of beneficial micronutrients to the soil).
While none of these methods works 100% of the time, you may have some success in keeping the slugs off long enough to allow your crops to provide a viable harvest.
Slug Repelling Plants
You can also use certain plants to encourage slugs to steer clear of your growing areas. Planting the following plants amongst your edible crops could help keep them at bay:
While these plants may not keep slugs away entirely, they can help you to steer them away from more susceptible plants in your garden or polytunnel.
You can also use plants such as lawn chamomile (which attracts slugs) as a trap crop to keep slugs away from more valuable vegetables or other favourite plants.
If you are overrun by slugs, you can also consider making a nightly patrol and gathering up as many culprits as you can find. Slug traps can make it easier to remove an over-population of slugs from your polytunnel or from elsewhere in your garden. Slug traps that people have made include:
- Half grapefruits, turned over on top of the soil.
- Empty beer bottles or soft drink bottles.
- Yoghurt pots buried in the soil with a lid of some kind on top.
Remember, however, that while you may be tempted to try to eradicate every single slug from your garden after they have destroyed plants that you have lovingly tended, it is not a good idea. It is a very bad idea to try to get rid of every single slug.
Why You Do Want Some Slugs Around
While it can be tempting to think of slugs as the enemy, in fact they are a crucial component of the garden ecosystem. While we should and can take measures to keep the slug population in check, it would be a big mistake to try to eradicate them entirely. Removal is not a long term solution as getting rid of them can create a vacuum that can cause a population boom and make the problem worse in the long term. What is more, getting rid of the slugs will naturally cause a drop in the populations of their predators. So when the slugs inevitably move back in, it will be even more difficult to get rid of them in the future.
Damaging the ecosystem by removing one link in the chain can have a knock on effect on the entire garden ecosystem and make it harder to maintain your garden in the future. That is why you will likely always have to deal with a few slugs, and managing them, rather than eradicating them, should be your ultimate goal.
Nematodes are sometimes touted as a natural solution to a slug problem, but while this is a natural solution for the short term, long term it could contribute to an imbalance of the ecosystem and so should be viewed as a last resort.
Do you have a slug problem in your garden? If you have any tips about getting rid of slugs and overcoming this common problem, let us know in the comments below.
Elizabeth Waddington is a writer and green living consultant living in Scotland. Permaculture and sustainability are at the heart of everything she does, from designing gardens and farms around the world, to inspiring and facilitating positive change for small companies and individuals.
She also works on her own property, where she grows fruit and vegetables, keeps chickens and is working on the eco-renovation of an old stone barn.