Make a beer trap
Slugs and snails love the sweet yeast smell of beer. …. The slugs and snails are attracted to the beer, fall in and drown. 1 Dig a hollow in the garden and place a small plastic container so the lip of the bowl is 5-10mm above ground level. Fill the container with beer.
2 To keep the rain out, place an upturned pot or ice cream container over the bowl, cut holes at the bottom of your upturned container or sit it on pieces of wood, so the snails can get in.
3 A brick or large stone on top will stop it blowing over.