Learn how to deal with and kill slugs in your garden.
Scientific name: Arion vulgaris (air-breathing, land slug or Spanish slug).
Taxonomic class: Gastropoda (this class includes slugs and snails).
Slugs are an all too common nuisance in our gardens. There’s nothing more infuriating than seeing your plants jumping into life in the Spring, only to be demolished by slugs in a matter of days (or minutes).
Facts about slugs:
- Slugs are hermaphrodites, which means they have both male and female reproductive systems and they can reproduce quickly and often. They can lay thirty-five eggs, a few times a year.
- Slug eggs are laid underground and hatch within two to three weeks. Baby slugs reach adulthood in approximately six weeks.
- Slugs live for two to six years. They grow larger and eat more and more plants every year.
- Slugs have twenty seven thousand teeth and can eat double their body-weight in one day!
- The average-sized garden in the UK contains two hundred slugs, and each slug can eat nearly a whole kilogram of plants in one season.
- Dark, moist, sheltered areas (by day).
- “Tasty”, succulent, leafy plants (by night).
Plants most affected by slugs:
- Any plants with succulent, green leaves (e.g. Delphiniums and Hostas).
- New, soft shoots on plants.
Signs that you may have have an infestation of slugs:
- Slime trails.
- Holes in plant leaves.
- Completely eaten seedlings and young shoots.
Control methods and treatment of slugs:
Start by eliminating slugs’ favourite habitats. Cultural controls such as these will minimise the chances of slugs thriving in your garden.
- Prune/cut-off shrub branches that touch the ground, and trim grass edges.
- Remove and compost excess mulch and decaying matter on your borders, from the previous season.
- Locate your compost heap away from growing areas (slugs can happily thrive there - see below "how to dispose of slugs").
- Tidy your garden - clear out underneath decking, hoe weeds and break up earth clogs (eggs and slugs can be hiding in these hidden spots).
- Encourage natural predators to your garden (e.g. hedgehogs, millipedes, beetles, frogs and moles).
- Keep tender seedlings safe (e.g. by protecting them with cardboard toilet roll tubes).
Physical control -
- Remove slugs by hand: Pick up and dispose of slugs when you see them. Search for them at nightfall and cultivate your soil in Spring when slugs are hibernating.
- Create barriers:
- Plant barriers - Slugs dislike the smell of some plants. Plant mint/chives/garlic/geraniums/foxglove/fennel around the edges of your garden.
- Slippery barrier - Rub petroleum jelly around the tops and bases of your pots. Slugs will struggle to crawl on it.
- Gritty barriers - Slugs do not like crawling on grit. Sprinkle eggshells/grit/sand/crushed seashells/gravel/pine needles around the base of your plants.
- Other barriers - Try sprinkling hair/sawdust/moist vermiculite/soot around the base of your plants.
- Beer traps - This is my preferred method. Fill a shallow container with beer and place near the base of your plants. The slugs will drink the beer and as they do, fall in. The next morning, dispose of the dead slugs. My other half is Mr. Craft Beer Hour, and a self-confessed beer snob. We use “rubbish beer” and excess, out of date beer.
- Grapefruit traps - Half a grapefruit (eat the flesh) and cut a small hole in the skin. Place the “empty” halved-skin upside down around your garden. Wait a couple of days and the slugs will be attracted to eat the grapefruit skin and will collect inside it. Collect them up and dispose of them.
Cultural control -
- Spray solutions - you can create your own sprays to repel slugs in your garden. Here are some of my favourite mixtures to try below. Mix the ingredients up and add to a spray bottle. Then spray your plants that are most susceptible to slug attack.
- Yucca leaf and water
- Garlic and liquid paraffin
- Chillis and water
- Vinegar and water
- Homemade bait - you can use these common store cupboard essentials as bait to kill slugs in your garden (or deter them from eating your plants):
- Oat bran - slugs love oat bran, but it will kill them once eaten.
- Cat food - slugs will be attracted to eat the cat food instead of your plants. The cat food will also attracted hedgehogs which will eat the slugs.
- Companion planting - specifically plant plants to deter slugs from eating your other plants (e.g. comfrey). Pick the slugs off as you see them and dispose of them.
- Plant choice - Only plant plants that slugs dislike (e.g. Artemesia, Cornflower, Forget-me-not, Fuchsia, Hydrangea, Lavender, Nasturtium, Peony, Tulip , Wallflower); and avoid planting plants that slugs particularly like (e.g. Hosta, Delphinium, Ligularia).
Biological control - attract natural slug predators:
- Hoe your garden to expose slug eggs - predators such as birds will eat the eggs.
- Build a wildlife garden - dig a pond to attract frogs and toads; position a bird bath and bird table to attract birds; put down food to attract hedgehogs.
- Nematodes - water nematodes, mixed with water into the soil using a watering can. They kill slugs above and below ground and should remain active for six weeks.
Chemical control - You can use pellets or chemical slug spray to kill slugs. Generally, I do not like using chemicals as they can affect other wildlife. There are so many other methods of slug control to try first.
How to dispose of slugs (dead and alive):
- Living slugs - add to the compost bin as there is plenty of food for them in there. They won’t move out the compost heap and will help break down cardboard and paper to improve the structure of your compost. Strong garden compost makes stronger plants; and stronger plants will survive slug attacks better than weak plants.
- Dead slugs- add to the compost bin too. The living slugs will eat them and become stronger slugs (better for breaking down your compost).
- You can also feed slugs to cats, ducks and fish as they are full of protein. I think my cats would turn their noses up at a slug on their dinner plate, but it’s worth a try!
If you have any questions about slugs or a pest affecting your plants, please comment below or get in touch.