Answer: Slugs like a damp and shady area, so it's understandable you have had problems. Here are several things to try, in my experience taking action early in the season can help ward off a larger population later. It can also take a year or two to really get things under control.
In early spring, lightly rake the soil and fluff the mulch to disturb and expose baby slugs and overwintering slugs to the cold and to predators such as birds. Avoid watering in the evening as the evening dampness is an attractant. Hand pick at night (I use tongs) and drop them into soapy water. Set out traps baited with beer or fermenting yeast and empty them regularly each morning. As a last resort, use commercial slug bait being very careful to follow the label directions.
While you are working on reducing the slug population, you can protect plants by making a ring around them with a sprinkling of diatomaceous earth (horticultural grade, not the kind for swimming pools) on the soil surface. This is a powder available in garden centers.
Lastly, keep in mind that natural predators such as birds, toads and snakes can be your allies in the battle. Children can sometimes be hired to catch them (the slugs) in the evenings for pocket money, too.
Good luck with the battle.
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