Slug and snail control – the green way

(First published July 2007, updated March 2010)

Slugs and snails are the bane of many gardeners, so here are some earth friendly tips for controlling these often unwelcome visitors.
Steer clear of snail and slug bait containing metaldehyde or methiocarb wherever possible. These chemicals have killed countless thousands of domestic pets and birds over the years; not to mention beneficial insects and earthworms. Metaldehyde is toxic to all creatures that consume it, be it through direct ingestion or secondary poisoning from consuming poisoned prey.
Iron phosphate is considered a more environmentally friendly pesticide and according to the EPA, no toxicity has been seen in mammals, birds, fish, beetles and earthworms if applied per the manufacturer’s instructions. Snails and slugs stop feeding and die within 3 to 6 days after consuming iron phosphate laced bait.
If you would like to steer clear of commercial poisons and pesticides altogether, there are other ways to control snail and slug populations:
– Consider a snail and slug hunt if you’re having big problems to initially thin the numbers down. This should be done late at night when they are most active, so you’ll need a torch and you might want to inform your neighbours first. I’m thinking a few torch lights shining around your front yard might incite some nervous neighbours to call the police; fearing burglars are on the prowl!
You can make it a family activity, complete with gloves or tongs if members of your family don’t like the idea of touching them. Offer an incentive for the most slugs and snails captured!
– Create simple traps such as upside down plant pots and wooden boards. Snails and slugs like these sorts of places to hide in. You’ll need to check the traps daily.
– Check regularly under rocks, logs and any thick vegetation you have in your garden. Remove any unnecessary items that snails and slugs could gain shelter under.
– Snails and slugs are repelled by the reaction of the slime on their bodies and copper. Try creating a barrier with copper strips around delicate areas of your garden or use copper tape on larger plants. These products should be available from your hardware store.
– Crushed eggshells are said to be an effective barrier; so too are pine needles straw, sawdust and shredded bark.
– Avoid over watering your garden and use direct watering methods where you can. Snails and slugs are attracted to moist areas so if your garden bed is relatively dry on the surface between the plants, this will help discourage activity. As snails and slugs are most active at night, try to water in the mornings so the top layer of soil has a chance to dry out.
– Frequent hoeing of bare areas of your garden can help bring eggs to the surface where they’ll be feasted upon by predators. Slugs also spend a good deal of their time below the surface, so turning over the soil helps to expose them to predators as well.
– Consider planting “repellent” species in amongst your other plants. These include Lavender, Thyme, Sage, Geraniums and Mint.
– Snails and slugs love beer. Some people use beer traps which is just a shallow dish with beer poured in, but an interesting variation on this is to spray beer on weeds so the snails eat those instead of your plants.
Snails and slugs are quite hardy creatures, so you’ll need to be thorough in your disposal of them. Depending on where you live, your local lizard population may find them a tasty treat; turtles definitely love them as do ducks and chickens. Something to be careful of though – find out if your neighbours use metaldehyde or methiocarb baits first. As it can take a while for the snails to die after ingesting these poisons, there’s the possibility the snails may have travelled to your yard from theirs.
If you don’t have any animal helpers to assist you in disposing of them; you’ll need to crush them thoroughly. For the squeamish, they can be drowned in a bucket of soapy water (the soap prevents them climbing up the sides). Use an earth friendly soap or detergent so you can then bury the remains in your garden and help return nutrients to it.
It’s my understanding common garden snails (Helix aspersa) can also be eaten by humans. They are high in protein, low in fat and are one of the species used in the snail dishes of France. However, because they may feed on a wide variety of plants and decaying matter; the contents of their stomachs may be toxic to us, so they require purging. From what I’ve read on the subject, this is done by feeding them greens or corn meal for a couple of weeks, paying particular attention to ensuring the container they are kept in is kept clean. If you’re considering consuming garden snails, as with feeding the snails to animals, check with your neighbors if they have been using metaldehyde or methiocarb baits. Ensure you do further research into the processes required to ensure safe consumption.
Here’s an interesting point – if you don’t have slugs and snails at all and this hasn’t been a result of your own efforts or local predators such as birds, it may be an indicator of high levels of toxins in your garden! The garden snail  is sometimes used as bioindicator of metallic pollution.
If you have any snail or slug control tips you’d like to share, please post them below!