Edible Landscaping

How to: Control Slugs and Snails

Slimy slugs leave mucus trails wherever they travel. They come out at night to feed on a wide range of plants.

Although they resemble edible snails, the common garden snail isn't worth trying to eat.

Spring is the time for spinach, peas, and radishes in the edible garden. It's also the time for slugs and snails.

The cool, wet weather provides perfect conditions for these mollusks to attack some of your favorite edibles. Slugs and snails actually aren't very picky about what they eat, but they especially like the young leaves and fruits of a wide range of spring plants such as lettuce, basil, broccoli, and strawberries.

Snails have hard shells, while slugs have soft and slimy bodies. In size they range from 1/4 inch to 5 inches long and can lay up to 50 eggs at a time. What's worse is they are hermaphroditic, so any adult can lay eggs. Some folks actually claim slugs are edible, but I have yet to venture into that food realm.

When slugs and snails feed, they create irregularly shaped holes in leaves. Since they do most of their damage at night, you often don't see the culprits unless you hunt them with a flashlight. Barriers, baits, and organic controls can be employed to keep slugs and snails at bay. Here are some suggestions for keeping them from ruining your spring garden.

Create the Right Environment

Plant in full sun, so the soil and garden stays as warm as possible. Grow your crops on raised beds and amend the soil with organic matter, such as compost, so the soil will warm up and dry out faster. Cultivate around plants frequently and avoid mulching. Slugs and snails love to hide in weedy patches and under mulch. Space plants further apart than normal to create more exposure to the sun and heat. Remove hiding places for slugs and snails, such as boards, stones, and debris. The exception would be placing old, broken, clay pots upside down in the garden to attract toads. A good population of toads may help keep your slug and snail population low. Other natural predators of slugs and snails include ground beetles, snakes, and turtles. You can also try releasing chickens and geese into your garden, but their stomping and pecking may cause more damage to the plants than the slugs.

Consider planting aromatic leaved herbs, such as rosemary, sage, and lavender, in heavily trafficked slug and snail areas. These critters seem to avoid these pungent herbs.

The feeding of slugs and snails cause irregularly shaped holes on plant leaves.

Block Those Mollusks

You can prevent slugs and snails from reaching your beds by surrounding them with the right materials. Slugs and snails hate crossing copper. You can use copper mesh fencing or copper flashing strips to keep them out of a prized bed or container. Attach the copper flashing to the top of the bed or container and slugs and snails won't cross it. The copper reacts with the slug’s and snail's slime, creating a chemical reaction that's similar to an electric shock to the mollusk. For beds without sides, use copper fencing, erected 4 inches tall around the bed to keep them away. Whether in beds or containers, try to remove the slugs inside the bed by handpicking at night before building your barriers.

Some gardeners have had success with other barriers, such as sharp sand, diatomaceous earth, and coffee grounds. Sprinkle these around affected plants and beds to keep the slugs and snails away. Reapply after a rain. The English place sheep's wool around prized plants to keep these pests away. It seems the wool is scratchy and contains chemicals that repel slugs and snails.

Traps

Anyone who’s been gardening awhile probably knows about slug beer traps. Slugs can't resist the yeast in beer and are drawn in to drown. Whether you create a homemade trap or buy a commercial one, fill the tub to within one inch of the rim with beer. The slugs will stretch and reach for the beer, fall in, and perish. Clean out the trap each morning and replenish with fresh beer.

You can also place boards or even upside down melon rinds in the garden. Come out early the morning and scrape off the slugs and snails that have accumulated underneath into a pail of soapy water to kill them.

Beer traps is a popular way to control slugs and snails. These mollusks can't resist the yeast in the beer and drown getting a drink.

Baits

If hand picking, barriers, and traps aren't controlling your slugs and snails effectively enough, then try baits. While there are chemical baits, such as metaldehyde, that are effective, these can be harmful to wildlife, dogs, cats, and young kids if ingested. I'd rather stick with iron phosphate. Iron phosphate bait is sold under brand names such as Escar-Go or Sluggo. It has a slug and snail attractant in it. The slugs and snails consume the iron phosphate, which kills them within a few days. Iron phosphate is a naturally-occurring mineral and is safe for use around wildlife, pets, and people.

Spread baits after watering or during periods of cool, wet weather when slugs and snails are most active. Spread bait in the late afternoon or evening in areas where these pests like to feed. Slugs and snails will often come back to the same spot to feed repeatedly. Also spread the bait in consistently moist areas, such as around a rain downspout or sprinkler. Iron phosphate can get somewhat wet and still be effective, but after heavy rains it will need to be reapplied.

Other stories on slug and snail controls:

Slugs and Snails
Snails and Slugs
Slug Fest

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