Non-Toxic Ways to Get Rid of Slugs and Snails

The damp, cool conditions that have haunted California's Central Coast lately are not every human's cup of tea, but if you're a snail or slug, you're in heaven.

Gardeners who go outside in the early evening will probably notice, to their dismay, hordes of snails gliding toward tender shoots and newly opened buds, ready to munch. There's been a population explosion among the slimy land mollusks of late, and your yard looks like a smorgasbord to them.

"It's a constant battle," said Paul McCollum, a member of Monterey Bay Master Gardeners who lives in Aromas, California, where he spends many evenings plucking snails from his roses and vegetables.

This spring marks a banner year for snails, probably due to the large amounts of rain that have fallen. Their eggs can lay dormant for years in the soil, only hatching when enough precipitation falls. Lots of rain means lots of snails, which immediately start looking for leaves and flowers to eat. And when they find what they want, they can consume several times their body weight each night.

So how do you get rid of them? There are probably as many remedies as there are snails.

The traditional method has been to buy commercial snail bait, which uses one of two poisons to kill the slimy beasts: metaldehyde or iron phosphate. Metaldehyde is hazardous to other creatures, while iron phosphate only kills garden pests.

Iron phosphate is the active ingredient in Sluggo Plus, which is Helaine Tregenza's favorite weapon in the fight against snails. Tregenza, an organic gardener in Del Rey Oaks, California, and proprietor of The Raised Bed garden service, said she uses Sluggo Plus as well as some other methods for discouraging snails.

"I tried beer traps, but it took way too long to get all the snails," said Tregenza, referring to one type of lure (see below).

But she notes that some basic garden maintenance can also discourage these hungry pests.

"The best thing to do is look under the plants and clear away any debris, because they like to hide in the nooks and crannies," said Tregenza. Also, tilling the soil regularly can destroy snail eggs stashed there.

McCollum said a tried-and-true, totally organic method is to pick up snails in the evening or early morning, and then crush and dispose of them. "You have to dedicate yourself to it," he said, or perhaps pay your grandchildren to do it - "a penny a snail."

Ducks and geese will readily eat snails, but as McCollum points out, "The trouble is, they'll eat other things too, like plants."

There are a whole host of things that can be used as barriers to snails, with just about all of them safe for people and pets. For instance, copper repels snails and slugs, and so Tregenza winds copper tape, available at nurseries, around her vegetable beds. Copper pennies can also be employed as a barrier.

Tregenza also spreads Sluggo Plus along her fence line to kill any snails that are migrating from her neighbor's yard.

"If you're growing food, you don't want that (toxic) stuff around them," she said of snail bait containing metaldehyde.

One natural way, which has been studied by U.S. Department of Agriculture scientists, really does work. It's been found that coffee kills snails and slugs quite well, and it can be sprayed around plants, on leaves, or directly on the mollusks. Research by the USDA in Hawaii showed that a 1 to 2 percent caffeine solution killed slugs and snails within two days.

Coffee grounds can also be used around the base of the plant, which will also enrich the soil.

Here are a few other methods that gardeners use, with varying degrees of success:

• Diatomaceous earth, spread over the soil, will kill snails, slugs and other garden pests. It's a powdered rock made up of fossilized diatoms, which have small sharp edges that damage snails' soft bodies. It will need to be reapplied periodically when rain or irrigation washes it away.

• If you have toads or frogs in the garden, don't get rid of them. They love to eat snails and slugs. You can buy ceramic toad houses to encourage the amphibians to move in. It's also said that garter snakes, salamanders, turtles and birds like to snack on snails.

• Place ceramic pots upside down in problem areas; check daily and remove snails and slugs that have hidden there.

• Set snail traps. Dig a hole in the ground and place a shallow container (like a used cat food or tuna can) so that the edges are even with the soil. You can use beer or grape juice as a lure, or fill with water and mix in a half-teaspoon of yeast and 1 tablespoon of sugar. Any of these will attract snails, which will crawl in and drown.

• Dryer lint can be used as a barrier around seedlings and plants. It's thought that hair or fur also is a deterrent.

• Powdered ginger or crushed eggshells placed around plants may also hamper snails, and eggshells have the bonus of adding calcium to the soil.

• Some people have used talcum powder, lime, or wood ashes as a barrier. However, if using ashes, don't let them touch the plants.

• Landscaping materials that may discourage snails include wood chips and gravel.

• It's said that there are some plants that snails don't care for, including freesia, daylilies, mint, rosemary, azaleas, fennel, cosmos, parsley, basil, conifers, foxglove, tansy and hibiscus.

Sources:

Personal experience

Interviews with Paul McCollum and Helaine Tregenza, May 2010

http://www.familymatters.tv/level_4/homeandgarden/snails.htm