Slugs are one of the most common garden pests, though unlike most other leaf-munching critters you find in your garden, they aren’t insects. Instead, slugs are land-dwelling mollusks that are more closely related to clams than beetles or caterpillars. Facing a slug infestation is serious business, filled with slime trails, damaged leaves, and missing seedlings. Figuring out how to get rid of slugs in the garden without turning to harsh synthetic chemical slug baits, is a task ripe with old wives’ tales and useless homemade remedies. But, the truth is that effective organic slug control is both manageable and affordable, when you’re armed with the following tips and information.
Why is garden slug control so challenging?
Let’s start with the obvious: slugs have a major ick factor. They’re slimy and pretty darned disgusting. Most species are decomposers who feed on decaying plant and animal wastes. But, there are a handful of slug species that prefer to feed on living plant material, making them the bane of many gardeners. If you’re here to figure out how to get rid of slugs in the garden, these are definitely the species you’re dealing with.
Unlike snails, slugs don’t carry a shell on their backs. Instead, they have a small, saddle-like plate called a mantle. Because they lack the protection of a shell, slugs tend to feed primarily at night or on rainy days, when they’re protected from the sun. During the day, they tend to hide under rocks or in other dark, moist locations.
Garden slug control can be difficult because many times the problem is misdiagnosed and the damage is blamed on another garden pest. Since slugs feed primarily at night, gardeners tend to notice the damaged plants, but they can’t find the culprit when they search the garden during the day. So, the cause of the damage becomes a mystery and the gardener might choose to spray the plant with a general insecticide in an attempt to kill the bug, which is useless, of course, against a mollusk like a slug.
Aside from frequent misdiagnoses, getting rid of slugs in the garden can be problematic because good old hand-picking is both disgusting and super-challenging. Unless you’re a night owl who loves roaming the garden with a flashlight and picking up slime-covered mollusks and dropping them into a cup of soapy water, hand-picking slugs is no fun on so many levels. It’s easy to see why so many gardeners opt for skipping it all together.
If you really want to know how to get rid of slugs in the garden, you first have to learn how to properly identify the damage they cause. Then, you have to understand how to target the slimy buggers effectively and efficiently based on how they feed as well as how they breed.
What does slug damage look like?
Slugs are notorious for decimating young seedlings and many different tender-leaved plants. Here are some sure-fire signs that a garden slug control program is called for:
• If you come out to the garden in the morning and nothing remains of your seedlings but leaf mid-ribs and stumps, slugs are a likely culprit.
• Perfect, round holes in tomatoes, strawberries, and other soft fruits can also indicate a need to learn how to get rid of slugs in the garden.
• Ragged holes in leaf edges and centers is another sign of slugs.
• Slime trails on plants, walls, rocks, or mulch are another tell-tale sign of slug troubles.
How do slugs feed and breed? (I know, I know…. TMI)
Slug mouths are lined with tiny, grater-like teeth that shred leaf tissue before digesting it. This type of feeding creates holes with jagged edges, rather than the smooth-edged holes often left behind by leaf-chewing beetles or caterpillars. Slugs move on an excreted mucus trail that serves to both protect their body from desiccation and message other slugs about their presence (apparently slime trails can help you find a mate…).
Most slug species are hermaphroditic, which means they have both male and female reproductive parts. Thankfully, slugs aren’t capable of fertilizing themselves, so they have to find a partner to breed (imagine all the little baby slugs there would be if slugs could fertilize themselves… yikes!). Slug mating is actually really fascinating; leopard slugs in particular. It involves a pair of glowing blue reproductive organs and a nocturnal tryst while hanging mid-air on a thread of slime. And, no, I’m not joking.
Each slug is capable of laying hundreds of eggs over the course of its lifetime, though the eggs are laid in clutches of about 30. The eggs are laid in moist soil, under mulch or rocks, or beneath leaf detritus. They’ll sit dormant if the weather is too hot, too dry, or too cold, waiting for just the right moment to hatch. If you live in a rainy region, such as the Pacific Northwest, you’re all too aware of why learning how to get rid of slugs in the garden is so important.
Now that you understand a bit more about these garden pests, it’s time to look at some ways to keep slugs out of the garden naturally.
How to get rid of slugs in the garden: 8 organic methods
1. Prevent slug damage with cultural practices.
This first strategy doesn’t involve products, traps, or barriers. Instead, it involves the actions you take in the garden.
Slug prevention techniques involve things like:
• Avoid using loose mulches where slugs are prevalent. Skip straw, hay, and shredded wood mulches and opt for compost or leaf mold instead.
• Avoid watering the garden late in the day. Since slugs (and their eggs) thrive in wet conditions, always water in the morning so the garden dries by nightfall.
• Switch from overhead irrigation to drip irrigation which targets water at the root zone and keeps plant foliage dry.
• Plant resistant plants. Slugs dislike plants with heavily fragranced foliage, like many common herbs. They also dislike plants with fuzzy or furry foliage.
• Slugs are a favorite food of many different predators. Encourage birds, snakes, lizards, toads, frogs, and ground beetles to make a home in your garden. Building a “beetle bump” is one of the most effective ways to control slugs naturally (find out how to build one in this article).
2. Stop using pesticides on your lawn.
Firefly larvae are one of the most prevalent predators of newly hatched slugs, and putting synthetic pesticides on your lawn doesn’t just kill the “bad” bugs, it also kills beneficial insects, such as fireflies, that live in the lawn and help you control pests like slugs. Instead, switch to organic lawn care techniques and let these good bugs help you control slugs naturally.
3. Trap slugs using boards.
This is one of my favorite tricks for how to get rid of slugs in the garden, especially the vegetable garden. Lay 2×4’s between crop rows at dusk and then the following afternoon, when the slugs take shelter beneath them to avoid the sun, flip over the boards and collect the slugs or cut them in half with a sharp scissors. You can also easily trap them underneath inverted watermelon rinds placed throughout the garden.
4. Use wool to control slugs.
If you want to know how to get rid of slugs in the garden, you shouldn’t ignore the power of wool. It’s been discovered that slugs are just as bothered by itchy, rough wool as humans are. They don’t like climbing over the coarse texture. Slug Gone pellets are made from natural wool that’s been compressed and formed into pellets. The pellets are spread around the base of susceptible plants and then watered. The pellets quickly expand, forming a thick mat of wool that slugs refuse to climb over. It lasts for a very long time and can even help suppress weeds.
5. Combat slugs with copper.
The metal copper reacts with slug slime to cause a mild electric shock and send the slug packing. You can purchase copper tape here and surround susceptible plants with a ring of copper. This is an easy technique if you just want to protect a few hostas, but it’s more challenging for larger garden areas. However, one easy way to keep slugs out of raised beds is to make a copper collar around the outer edge of the whole bed by stapling or nailing a strip of copper tape around the top of the bed’s frame. This also works for containers where the copper tape can be placed just inside the upper rim of the pot. There’s also a copper mesh called Slug Shield (available here) that can be used in a similar manner and is reusable. It’s a bit easier to wrap around a single plant stem than copper tape or strips.
6. Set up a slug fence.
Believe it or not, you can make an electric fence for slugs. Yep, that’s right. Here are plans to make a tiny electric slug fence to place around raised beds and protect the plants from slugs. It runs on a 9 volt battery and zaps the slugs when they come in contact with the fence. It won’t hurt humans or pets and is a great way to protect a raised bed or other small garden.
7. Set up a slug bar.
You know I had to mention everyone’s favorite/least favorite slug control: beer-baited traps. Yes, no list of tips on how to get rid of slugs in the garden is complete without a mention of beer traps. Plastic traps like these or these are baited with beer (non-alcoholic works best). The yeast in the beer attracts slugs who then fall in and drown. It works, but it’s also incredibly gross. In order to prevent a festering pile of slug corpse-infused beer, be sure to empty and re-bait the traps daily.
8. Use an organic slug bait.
When figuring out how to get rid of slugs in the garden, organic slug baits are a must. However, be smart about this method because not all slug baits are the same. Many traditional slug baits used to control slugs in the garden are poisonous to pets and other wildlife in addition to slugs. Do not use slug baits that contain methiocarb or metaldehyde as their active ingredient. Metaldehyde is extremely toxic to mammals (just a teaspoon or two can kill a small dog) and methiocarb isn’t much safer.
Instead, turn to organic baits for garden slug control. Look for an active ingredient of iron phosphate. These slug control products are safe for use on even certified organic farms. Brand names include Sluggo, Slug Magic, and Garden Safe Slug and Snail Bait. Sprinkle the bait on the soil surface around affected plants. The slugs eat the bait and immediately stop feeding. They’ll die within a few days. These baits can even be used in the vegetable garden around food crops, unlike traditional slug baits.
Other, marginally effective slug control methods
In addition to these “power 8” ways to get rid of slugs in the garden naturally, there are a few other tricks you can try, though their effectiveness is debatable.
• Diatomaceous earth has long been touted as a great slug control. It’s a fine powder that is very sharp microscopically and the edges easily cut through slug skin and desiccate them as they crawl over it. The trouble is that as soon as diatomaceous earth gets wet, it’s rendered useless. I don’t know many gardeners who have time to make a circle of dust around every plant and then replenish it after every rain or heavy dew.
• A hearty sprinkle of salt, placed directly on a slug’s body, may desiccate it enough to lead to its death, but there’s a good chance the slug will simply shed its slime layer along with the salt and carry on as usual. I’ve seen it happen so many times that I put aside my salt shaker long ago.
• And lastly, sharp-edged items, such as sweet gum seed pods, crushed eggshells, and dried coffee grounds have all been touted as great slug deterrents. I respectfully disagree and so do several studies.
The final word on these slimy beasts
If slugs consistently cause you troubles and you’re constantly asking yourself how to get rid of slugs in the garden, then it’s time to take action and maintain a good organic control program from the start of the growing season all the way through the end by using as many of the techniques described above as possilbe. Doing so keeps the slug population in check and significantly decreases the amount of damage they cause.
Have you battled slugs in your garden? We’d love to hear your success stories in the comment section below.
For more on controlling pests in the garden, be sure to check out the following articles:
Guide to vegetable garden pests
Managing four-lined plant bugs
Controlling squash vine borers organically
Preventing pests in your garden
Growing organic apples with fruit bagging