The Irish garden gets a huge amount of annual rain fall so slugs absolutely thrive here. We have a huge variety of slugs in the garden. Some of them grow to be the size of your thumb! The kids are in competition to see who can find the biggest one ever.
Taking a newly emerged seedling and plating it out in the garden is like feeding it to the sharks. So we have devised a system to keep the slugs off. We take an old milk bottle, cut the bottom off it, place it over the seedling and push it down into the soil. It becomes a small protective house in which the slugs generally don't tend to enter. The environment inside the milk bottle is also lovely and warm. When the seedling begins to push up and out of the bottle we remove it. At that stage the plant is usually large enough to handle a few slug bites.
One of our Wwoofers devised a solution for storing the milk bottles by threading rope through their handles and hooking them up.