The Best Natural Methods to Protect Your Garden from Slugs and Snails

April showers bring May flowers, but they also bring those slimy pests, slugs and snails.

Raiders of the night, they have a discerning appetite for succulent foliage and flowers. And from dusk to dawn, they can make short work of leaves, flowers, soft herbs, vegetables, seedlings, tender green bark, and ripening fruit.

The armored gastropods can become so prevalent in some locations that growing vegetables and ornamentals becomes difficult, if not impossible.

These sticky critters can overrun bird feeders and hide under the rim of pots and containers, resulting in handfuls of slimy, squished snails when they are moved – ugh! Now that is gross!

Two photos in a vertical collage showing a leopard slug and a snail. To the center and bottom of the frame is green and white printed text.

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If you enjoy visiting birds and other wildlife or have outdoor pets, you should control these pests in a safe and environmentally friendly manner.

Over the years, I’ve tried a variety of tricks and products to control slugs and snails. Some work well, others don’t; some are safe for other garden creatures, while some are deadly to all.

In my experience, management of slug and snail infestations is most efficient when a combination of tactics is used. Baiting and trapping make it easy to remove the creepy cousins, and barriers prevent them from accessing your plants.

Let’s have a look at the best – and safest – suggestions for controlling these pests, so you can enjoy your garden again!

Habitat and Habits

Not all nighttime marauding is caused by gastropods. An easy clue to determine who’s causing the damage is by the telltale trail of shiny mucous they leave behind – if a slime trail is present, you know the culprit is a slug or snail.

Snails and slugs both belong to the mollusk phylum, and have similar bodies and biology. The primary difference between the two is that slugs are without the snail’s external spiral shell.

A close up vertical image of a common Roman snail on a smooth rock.

They both propel themselves with a muscular “foot” that continuously secretes a slimy mucous to help them glide, and both thrive in similar environments.

Both types of gastropods prefer cool temperatures and are most active at night, or on overcast days. On bright, sunny days, or when temperatures are high, they’ll seek cool, shady havens to beat the heat and bright light.

In cold weather, they’ll hibernate underneath any debris that provides shelter, or burrow into topsoil. But in areas with mild winters, they can be active year-round.

Disrupt and Displace

A good starting point for your slug and snail management program is to disrupt and remove their daytime hidey-holes, to the greatest extent that you’re able to.

Preferred hangouts can be a tall stand of weeds or the underside of just about anything on or close to the ground – particularly in moist, shady areas.

Underneath boards, garden decor, planters, ledges, decks, low-growing branches, pot rims, debris, and protective ground covers are all prime real estate for gastropods.

A close up vertical image of a leopard slug crawling along a leafy stem.

To disrupt their environment, undercut low branches, burn weeds with a weed torch or trim weeds close to the ground, and remove any unnecessary material they can hide under.

Obviously, some areas like rock walls, decks, meter boxes, permanent bird feeders, and so on can’t be removed – but these spots make good locations to bait and trap.

Handpicking

If you have the stomach for it, handpicking is an effective option when practiced diligently.

To lure slugs and snails, water any infested areas at dusk. After nightfall, use a flashlight to hunt them down, pick by hand, and dispose of them – you’ll definitely want to use gloves for this option!

A close up horizontal image of a garden snail (Helix aspersa) eating holes in a cabbage head.

You’ll need to do this nightly until their numbers are decimated, after which a weekly foray should suffice.

Once caught, you can dispatch them in a bucket of soapy water or by spraying with a solution of diluted ammonia. One part ammonia mixed with 10 parts water in a spray bottle will do the trick.

Bait and Trap

A good point to remember is that to bait gastropods is to attract them – so keep bait and traps a safe distance from any plants you want to protect.

The Beer Dish Trap

Simply fill a shallow container with beer and sink it into the soil, then leave overnight. Slugs and snails are attracted to beer, glide over for a sip, then drown in it.

Remove the corpses in the morning, and refresh with their favorite suds!

Esschert Design Ceramic Slug Trap available on Amazon

Containers can be as simple as a plastic deli dish, or you can opt for something a bit more decorative – like this cute ceramic snail.

Hidey-Hole Trap

Create a welcoming environment for slugs and snails to hide under in the daytime with any flat object, or anything that makes a nice gastropod den.

A piece of plywood, thick dark plastic, pot saucers, overturned containers, or anything that will provide cool shade will work. The rinds of citrus (like oranges and grapefruit) and melon halves make an alluring den for them as well.

A horizontal image of two slugs attacking leaf lettuce in a veggie garden.

Water the area first, lay down the trap material, bait with a piece of leaf lettuce if needed, and return in a day or two to remove and destroy the crawly critters.

Repellents

A variety of repellents can be used to divert gastropods away from plants you want to protect.

Garlic

Researchers in the UK have found that garlic oil applied to the soil around crops will repel gastropods, and it kills those that come into contact with it.

An effective method for small-scale gardens is to crush garlic cloves (lots of them – easy to come by if you grow your own!) and lay them around the perimeter of the at-risk area.

Copper

The natural salts that form from oxidizing copper also act as a repellent. Uncoated copper flashing, banding, and mesh are all suitable options to lay around any area in need of protection.

Kraftex Copper Foil Tape with Conductive Adhesive

An adhesive copper tape, like this option available on Amazon, is a good option as it stays in place nicely, maintaining the barrier.

Vaseline and Salt

As the underside of planter rims is a favorite hiding spot, smearing this area with a mixture of Vaseline and salt will act as a repellent.

Coffee Grounds

Scientists have recently found caffeine to be highly toxic to snails and slugs. For use as a repellent, sprinkle used coffee grounds (full caffeine, not decaf) around the edge of flower and veggie beds.

Barriers

Gastropods have delicate tummy tissue, and any sharp materials will irritate and potentially cut their tender undersides.

For an extra layer of defense, build a small berm at least three inches wide with fine stone chips, crushed egg shells, diatomaceous earth (DE), or crushed oyster and clam shells.

A horizontal image of crushed egg shells on a cork surface.

Diatomaceous earth is derived from silicon dioxide and has sharp, abrasive edges. But it must remain dry to deter gliding gastropods.

Use food grade DE, not the material used in aquariums (which has smoother edges), and follow instructions when applying.

Biological Controls

For combating gastropods, my personal weapon of choice is beneficial nematodes.

One hundred percent natural, nematodes are naturally occurring microscopic worms that are mixed with water for application.

The best times to apply nematodes are once soil temperatures have warmed up in spring, and after intense summer heat has ebbed in late summer/early fall.

A close up vertical image of a snail on a green, leafy plant.

They won’t kill adult snails or slugs, but when applied to the soil, nematodes enter the gastropods’ eggs. They then release bacteria that kills the eggs, then feed off the eggs and reproduce before moving on – with an effective killing rate of about 90 percent.

People, birds, pets, and helpful insects such as bees, ladybugs, and earthworms are completely resistant to these hardworking microbes.

Nematodes move swiftly through pre-moistened soil, and can be applied with a hose and sprayer or with a watering can for smaller areas.

You won’t see immediate results with nematodes, but the following year you’ll notice a significant reduction in the slimy herbivores.

For best results, make three consecutive applications – spring/fall/spring, or fall/spring/fall. After that, an application once every 18 months will keep gastropod numbers at bay.

Timing is important with this method. A package contains millions of live nematodes, and if you don’t plan on using them immediately, they need to stay refrigerated until application. In the package, they have a limited shelf life of around two weeks.

Nematodes can be purchased online through various retailers. There are different species of nematodes, so be sure that the ones that you buy are listed for slug and snail control.

Before purchasing them, ensure soil temperatures are adequate, and that you’ll have the necessary time available for application.

Read our complete guide to doing battle against creepy crawlies with nematodes here.

Predators

Natural predators will also do their fair share in keeping slug and snail numbers down, provided you have a welcoming environment – which usually means no cats or dogs to chase them away.

A close up horizontal image of a young garter snake hiding in vegetation and rocks.

Some predators known to feast on gastropods include frogs and toads, garter snakes, lizards, hedgehogs, moles, thrushes, blackbirds, magpies, and rooks.

Which brings us to our final tip…

Escargot, Anyone?

They say revenge is a dish best served cold, but I like my escargot served piping hot with plenty of garlic and butter!

A vertical image of a group of grape snails in a pan with water being prepared as escargot.

If you have snails in the garden, chances are they’re the common, or brown snail, Helix aspersa (aka Cornu aspersum) – one of three main species used for escargot, along with H. pomatia and H. lucorum.

Brown snails have a soft, beige or brown body with a cream or yellow shell and brown spiraling stripes. When mature, they measure approximately 0.75 to 1.25 inches high, and about the same, or slightly larger in width.

Land Snails and Slugs of the Pacific Northwest

If you’re not sure how to identify them, you can always pick up a reference book for your region such as Land Snails and Slugs of the Pacific Northwest by Thomas E. Burke and William P. Leonard, available on Amazon.

Collect them at night (see Handpicking above) and place in an escape-proof bin. Sweeten them for one week with a diet of people-friendly food like lettuce, basil, carrots, melons, apples, and so on. This will improve their flavor and clean out their digestive tracts.

After sweetening, purge for two more days with no food or water.

After purging, place the snails in a lidded quart jar and put them in the fridge for about an hour – this will put them into a deep sleep before cooking.

To cook, par-boil for three minutes, drain, and remove shells. Rinse in water, followed by a bit of vinegar. Then prepare them following this delicious recipe for Bourguignonne escargot from our sister site, Foodal.com.

This is karma at its sweetest!

Of course, if you do plan to use this particular method of gastropod management, your garden should be free of all pesticides – including the so-called “safe” slug and snail baits.

Safe Slug Baits

At present, there are three different types of commercial slug baits sold in North America.

The traditional molluscicide in use since the 1930s uses metaldehyde, which has a highly toxic profile for pets and wildlife, and can find its way into waterways during heavy rainfalls – not a great option for anyone who’s looking for a safe, ecologically sound method to limit gastropod damage.

In the mid-1990s, a new molluscicide (available under various brand names) arrived on the market that uses iron phosphate as the active killing ingredient.

A close up horizontal image of a slug hiding in a crevice between a rock and wooden stump.

According to the EPA, iron (ferric) phosphate is considerably less toxic to pets, birds, worms, and other garden friendlies, and is generally regarded as safe (GRAS). But, it’s also fairly slow acting and can take up to a week to kill gastropods.

To speed up the killing action, an inert ingredient known as ferric sodium EDTA (sodium ferric ethylenediaminetetraacetate) was added to some iron phosphate baits – and is also sold as the primary killing compound in other brands.

However, ferric sodium can be toxic to pets and wildlife such as aquatic arthropods, and should not be used in or near aquatic environments.

Other brands combine iron phosphate and spinosad, a natural substance that is toxic to a variety of garden gastropod pests, but not to larger animals.

Containers of Sluggo Plus on a white, isolated background.

Sluggo Plus (iron phosphate and spinosad) available from Arbico Organics

If you do choose to use commercial baits, read the label carefully for toxic ingredients, and follow application instructions closely. And consider taking steps to keep pets away from these baits.

The Trail Stops Here

Slugs and snails are persistent in their foraging, so you’ll need to match their efforts.

Use a combination of traps and bait, handpicking, barriers, repellents, and predators to effectively control their environment and routines – and your plants won’t be bothered by the gooey little pests again!

A close up horizontal image of two snails climbing on squash plants.

What about you folks, do you have any garden problems or questions you’d like to see addressed about these hungry gastropods? If so, drop us a line in the comments below!

And for more information about battling pests in your garden, check out these guides next:

About Lorna Kring

A writer, artist, and entrepreneur, Lorna is also a long-time gardener who got hooked on organic and natural gardening methods at an early age. These days, her vegetable garden is smaller to make room for decorative landscapes filled with color, fragrance, art, and hidden treasures. Cultivating and designing the ideal garden spot is one of her favorite activities – especially for gathering with family and friends for good times and good food (straight from the garden, of course)!

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kaye walsh
kaye walsh (@guest_5989)
1 year ago

not too keen on killing them in the way you describe, if they were as big as a sea lion you might not look at them as insignificant life. I know they are a nuisance but some of the methods you employ are cruel. I find by relocating them away from your property will do the trick.

Dayle
Dayle (@guest_9112)
Reply to  kaye walsh
1 year ago

Humans need nature. Nature does not need humans. I can’t fathom why people are so lost on this fact. Keep up the fight. Every bug saved may be the one that matters. Hopefully… I hope you’re ready for what’s coming…

bob macbob
bob macbob (@guest_9211)
11 months ago

Spray with ammonia to kill them? This is just wrong! If you have to kill something, do it quick. Drop the snail on the ground, stand on it. No pain or suffering…

Cid Young
Cid Young (@guest_9694)
Reply to  bob macbob
11 months ago

I had my best defense against snails that was so incredible when I moved to Moss Beach, CA in the eighties and happened to acquire 2 sweet Khaki Campbell ducks. Not only was the female an awesome layer of high protein eggs, she simply lived to “help me in the garden” by devouring any snail she could locate. She ate so many, my neighbors would bring their snails in plastic bags just for her special snack.