Most gardeners cringe at the sight of slugs and snails, either because they are grossed out by them or because these animals can do serious damage to plants. They can certainly be pests, but they also have some positive attributes.
Slugs and snails are mollusks related to shellfish. Snails grow a protective shell over their soft bodies, and slugs go about “naked.” There are species found in both fresh and salt water, as well as some that are completely terrestrial. Some are vegetarian, some are scavengers, and some are carnivorous.
No matter what they eat, snails and slugs have a mouth equipped with a tongue-like structure called a radula, which they use like a nail file to scrape food into their mouths. Here’s how to eliminate—or learn to live with—slugs and snails in your garden:
Let them be delicacies for other critters.
The most important role snails and slugs play in your backyard ecosystem is as a food source for other wildlife. Amphibians feast on snails and slugs, as do some species of snake, including the ubiquitous garter snake.
Mammals, including shrews, skunks, and opossums, happily slurp up slugs and snails, too.
Many birds will also gobble these slimy invertebrates, especially elusive ground-feeding forest birds that won’t visit a feeder, such as wood thrushes, thrashers, and ovenbirds, as well as ducks and geese.
Snails are an important source of calcium for nesting birds. During the breeding season, female birds require extra calcium in order to form the shells of their eggs. Research shows that birds get a majority of their calcium by eating snails.
Remove their hiding places.
Snails and slugs are nocturnal, which means they come out after dark to feed. During the day they hide in moist, dark places (under rocks and logs and in decaying plant matter), so remove such hiding places near your plants. Also, make sure you water early in the morning, so the moisture snails and slugs love has time to dry up before nightfall.
Lay out some copper.
Copper repels slugs and snails. Lay a barrier of copper stripping (available at hardware or garden stores) around your garden beds or individual plants.
Go out at night.
Avoid poisons, which could harm other wildlife. Instead, set up homemade traps made of boards, overturned flower pots, and melon rinds to create damp, soggy places that will attract slugs and snails. Then go out after dark with a flashlight and remove the offenders from their hiding places. Drop them into a bucket of warm, soapy water. (Sprinkling salt on them works, too, but seems unnecessarily cruel.)
Give ’em a beer.
Snails and slugs are attracted to beer and other fermented liquids. If you bury shallow dishes filled with beer (or a mixture of sugar, water, and yeast) so the lip of the dish is flush with the ground, they’ll fall in and drown themselves. Make sure the container has straight sides so they can’t crawl back out. Then treat yourself to a fresh beer, sit back, and enjoy your natural, mollusk-free garden!
The biggest slug around
One of the coolest invertebrates around is the bright yellow banana slug, which can grow almost 10 inches long. It’s the largest slug species found in North America. Banana slugs are native to the Pacific Northwest, from Alaska down into northern California. Unlike other slug species that damage garden plants, banana slugs are primarily scavengers, feeding on already-decaying plants, animal droppings, and mushrooms. Their slime has anesthetic qualities to help deter predators—so if you lick a banana slug, your tongue will go numb.