By Jennifer Copley (Last Updated 7 February 2011)
With approximately 27,000 teeth and the ability to consume twice its body weight in plants over the course of 24 hours, a single slug can chomp its way through nearly 2 pounds of plants each season.
Slugs are hermaphroditic, and each slug can produce more than 100 eggs per year. These eggs, which look like shiny off-white or translucent spheres, hatch in just 10-21 days. A slug takes only 6 weeks to reach adulthood and can live for up to 6 years.
The first line of defense against a slug invasion is to keep your garden clean. In particular, remove any decaying plant matter from borders and beds regularly. In addition, hoeing your garden will expose the eggs, allowing predators to eat them.
If your garden has already been taken over by slugs and snails, there are ways to get rid of them or even use them productively that won’t pose a risk to people, animals, or the environment.
Create a Slug Barrier to Prevent Invasions
There are a number of ways to create environmentally friendly slug barriers:
- Grow plants slugs dislike such as chives, ginger, mint, foxgloves, fennel, lavender, thyme, stinging nettles, borage, lemon balm, tansy, hyssop, and geraniums around your garden’s border (some gardeners recommend garlic as well, though others say that slugs will happily eat their way through it).
- Surround plants with oak leaves (slugs and snails don’t like the tannins these leaves contain).
- Encircle your garden with pine needles, crushed gravel (the kind with sharp edges), crushed nuts, sawdust, coarse mulch, thorny branches, holly leaves, or egg shells, as slugs and snails will avoid sliding over these sharp surfaces.
- Add water to vermiculite so that it swells and then place the mixture around your plants to create a wobbly surface that deters sliding creatures.
- Place 3-4 inches of seaweed around the bases of your plants or garden beds (when it dries, it will be around 1 inch deep). Push the seaweed away from your plant stems so that it doesn’t make direct contact. Slugs and snails hate seaweed because it’s salty and has rough surfaces when it dries. An added bonus of this method is that seaweed is a great soil conditioner.
- Purchase copper tape from a garden center and wrap it around the bases of potted plants. Slugs and snails receive a small shock when they attempt to climb the pot.
Distract Your Slugs with Slug Traps – and Put Them to Work in Your Compost
There are a number of ways to distract slugs from their primary targets, one of the simplest of which is to provide grapefruit houses. Take hollowed-out grapefruit shells, create slug-sized holes that will act as doorways, and place the grapefruit halves around your garden (rounded side up). Slugs love grapefruit, so if you leave the houses for a couple of days, slugs will gather within them, after which you can add the live slugs and houses to your compost pile or bin.
Because slugs will find a buffet of their favourite foods among the compost, they’re inclined to stay put and assist in breaking down paper and cardboard. This is a good way to put slugs to work improving your compost. Some gardeners are concerned that when they spread the finished compost on their gardens later on, they’ll be spreading slug eggs as well, but a combination of heat, predation, compression, and time should kill the eggs before the compost is used. Just make sure you don’t add any live slugs and snails back into your garden when you add the finished compost.
Another way to gather slugs together is to cut an old piece of carpeting into squares, soak the squares with water, and scatter them around your garden. Slugs will come to roost on the carpet pieces, after which you can dump the slugs into your compost pile and reuse the carpet squares to catch more slugs in the future.
Another great distraction is comfrey, a slug favourite. Plant comfrey in slug hotspots to draw slugs away from your other plants. They can then be plucked from the sacrificial comfrey and added to the compost pile.
Slugs and snails also love beer, and many gardeners get rid of them by filling a shallow bowl with beer in which they drown, but beer can be used to put these pests to work for you. Simply spray beer on your weeds and let slugs and snails do your weeding while you sit back and relax.
Bring Slug Predators to Your Garden
Encouraging predation is a way to kill slugs naturally without having to do the dirty work because other creatures will be the agents of slug doom. To encourage slug and snail predators to spend time in your garden:
- Add a pond and some low, dense vegetation to your garden to attract toads and frogs.
- Provide bird baths, bird feeders, or trees and shrubs with berries to draw birds.
- Leave some long, rough grass to encourage shrews.
- Keep chickens or ducks – they love to eat slugs and snails.
- If you live on a continent where there are wild hedgehogs (Europe, Asia, Africa, or New Zealand), encourage one to move into your garden by providing a waterproof wooden nesting box filled with straw and covered with leaves. You can draw a hedgehog to the area by putting out dog food, but this is a risky strategy, as it may attract other animals as well.
For more eco-friendly garden ideas, see How to Create a More Environmentally Friendly Garden. For more safe, non-toxic plant protection solutions, see Natural Garden Pest Control. For a full list of garden articles, visit the main Gardening page.
- Eartheasy Solutions for Sustainable Living. (2010). “Natural Slug Control.” Eartheasy.com.
- Ford, S. (2003). 50 Ways to Kill a Slug. London: Octopus Publishing Group, Ltd.
- GardenAdvice.co.uk. (n.d.). “ Slug Problems.”
- Garden Organic. (n.d.). “Composting Myths Exposed.” HomeComposting.org.uk.
- Hayward, M. (n.d.). “Slug and Snail Trail.” Haywardm.Supanet.com.
- The Romborough Gardens Allotment Association. (n.d.). “ General Slug Tips.” Homepage.NTLWorld.com.