Slugs and hostas go together like peanut butter and jelly, or like potatoes and potato bugs. They love a moist environment, with plenty of dead foliage and debris to hide in. But you don't have to resign yourself to excessive and unsightly damage to your hostas. Slug baits are readily available from gardening centers, and non-chemical alternatives exist that may work just as well, while avoiding potentially harmful substances.
Weed your hostas aggressively. Good cultural practices go a long way in preventing slug damage. Clean up weeds, fallen leaves and all debris immediately. Dead foliage creates a slug haven.
Water your hostas properly. Be thorough, but water just enough to keep the top 1 inch of soil evenly moist. Excessive moisture attracts and accommodates slugs, but you do need to provide enough to keep your plants healthy. If you're not watering sufficiently, hosta leaf tips will dry and brown.
Cut the top 6 to 8 inches off of an empty plastic 2-liter bottle. Discard the bottom of the bottle and the cap. Cover a seedling or very young hosta with the top of the bottle and sink it deeply into the soil around the plant. This shield will protect it from slugs, which have a taste for young hosta plants.
Hand-pick slugs from your hostas and the planting site. Make this action your first mission early in the morning and the last as the sun goes down. Slugs are nocturnal feeders, so plan a hand-picking party by moonlight if you're especially zealous. Drop the little beasties into a bucket of soapy water.
Place empty plastic bowls in your hosta planting area. Margarine and cream cheese containers are perfect. Space them about 3 to 6 feet apart. Open a can of cheap beer at dusk and fill the containers with it. Fresh beer works much better than stale brew. Slugs will crawl into the bowls overnight and drown. Dump the contents near your planting site to alert living slugs to the presence of a free nightcap. Repeat this nightly.
Cut your hostas back to ground level when foliage dies late in the year. Remove all plant material from the area.