Alys Fowler

Ways to control slugs and snails in your garden

You can control slugs and snails with any kind of bait, organic or traditional. Explore all the options with Alys.

Now that the soft May rains have appeared so have the slugs. If we felt like we were getting away scot-free this spring, nature has reminded us otherwise. I went through the garden last night squishing and stamping, whilst crying ‘no, no, no, not that too’, as large and fat and small and thin slugs decimated my delicious cabbages.

Slugs and snails have a very fine palette, if you like to eat it then there’s a good chance they do too. Just like you they dislike bitter flavours and like soft, buttery lettuces as do they. You can’t eat everything a slug or snails can, but it’s amazing how similar our palettes are. Our plant breeding tendencies tend to make more of this too, we bred for tenderness, sweetness and leaf shape, rather than more bitterness to keep the slugs at bay. In short anything tasty you try and grow this summer will be slug fodder if you don’t take some action.

Traditional slug pellets v organic

Traditional slug pellets are made from metalydehyde, a poison that attacks the slug’s mucus membranes causing the slug to produce massive amounts of slime and dehydrate. If the slug is small it will be killed outright, if it’s a large slug or only a little of the pellet it eaten then the slug will become immobilised and fail to retreat to its daytime hideout.  Although Metalydehyde eventually breaks down, it takes some time and will travel into the system of anything that eats the dying slug. This is not good for wildlife. It’s not good for us too because it’s been found in every human being, even babies - our over reliant use of the stuff in agriculture means it’s in our water and soil systems. Worse still, at best slug pellets tend to only kill around 10% of the slug population in your garden so they are not that effective.  

What are the other options then? There are ‘organic slug’ pellets based on Ferris phosphate and cause both slugs and snails to stop feeding when a number of pellets are consumed. They are safe to pets and break down in the ground to iron and phosphate. However, if the slug only eats one pellet it gets a stomach aches and doesn’t go near them for at least a month. It’s turns out slugs have quite good memories and remember pain for up to 50 days after they first experienced it. Used properly, scattering them wide and far, rather than a big fat line of them and they can be useful. Particularly if they are used in conjunction with Nemaslug, a biological control that introduces naturally occurring nematodes (tiny worms) that feed on slugs into the soil.

I’ve recently started trialling a product called Zlug which is a blend of herbs that you place around the plants you want to protect and the slugs don’t like traveling across it. Its natural, biodegradable, smells lovely and harmless to other wildlife. I’m still working out how effective it is, but early trials show that it works well. I’m interested to see how it works in the rain!

None of these solutions are particularly cheap and you can rely on some free stuff to help you out.

Beer traps

These are containers, jam jars, sunk into the ground so that the lip sticks upabout an inch from the soil, filled with beer. Slugs and snails love beer and come to sop up all that hoppy loveliness and then drown. The reason you make sure the lip of the container sticks up a bit from the soil is to stop lovely ground beetles from falling in. Ground beetles are curious and often hunting for slugs, so if they see lots of slime trials they’ll head off to find supper and accidently fall in. You do not want this to happen because beetles eat a lot of slugs and slug eggs.

The best beer traps are made from hoppy, malty ales. Larger really isn’t that attractive to slugs. Rather than buy expensive beers for your slugs, make friends with your local pub and give them a slops bucket with a tight fitting lid. All the left over bits of pints, as well as fruit juice and coke (slugs have a very sweet tooth) make a perfect if disgusting brew for your traps. You’ll be astonished how many slugs you catch. You can tip them straight onto the compost, where they will rot down.

Wildlife

Encourage birds such as thrushes and blackbirds who are all partial to eating young slugs, into your garden, by feeding bird seed all year-round. You need to be thought of as a reliable place to eat and hang out in. Small birds like shrubs and other hideouts away from neighbourhood cats to hang out in. Hedgehogs eat a number of slugs too, so make sure your garden has access for them to get in. Our modern sturdy fences and garden walls are making life tough for hedgehogs, so make a door way (it doesn’t need to be more than 15-20cm high and that wide so that hedgehog can pass from one garden to the next.

Frogs and toads like slug and snails’ eggs and babies, though they don’t tend to eat the big beast. Having a healthy garden pond will attract this lot in.

Finally and this is hard one, slugs need somewhere to retreat to during the day, when its hot or sunny (when it rains they have a party). They usually hide under rotting timber, bricks, old pots, big stones and dank, hidden places. Snails are very fond of hiding in ivy and other evergreens such as box hedging. However, all these places are also important spots for their predators. Beetles like roaming around exactly the same conditions. Toads and frogs also like hanging out under leafy foliage and in old pots. If you tidy your garden up too much, you’ll banish the predators you so desperately need.