Let’s be honest, it’s not awesome when you reach down to gently pluck a new leaf from your lettuce plant and you end up with a handful of gooey slug-mush instead. Slugs typically aren’t a gardening-favourite, but these icky molluscs are easy to deal with, and usually not the end of the world.
Why They’re Good:
Slugs eat decaying matter (among other things), which helps to recycle nutrients in the ecosystem. They also provide an important source of food for birds, toads, and even some other insects.
When They’re Bad:
Slugs will eat plant material as well, and while the odd ‘chomp’ here and there won’t hurt your plant, too many slugs in one place can eat enough of your plant’s vegetation to damage crop yields or stress the plant.
Plus, they’re kind of gross.
Where & When You’ll Find Them:
Slugs thrive in wet environments, so you’re likely to find them on your outdoor garden beds during wet season, or anytime in damp or shady areas.
Slugs lay their eggs in spring and summer, typically in cool, wet conditions. Mediums such as soil or compost are perfect for them. You’ll see them from early spring and throughout the summer, as more eggs hatch. Here in Alberta, our typical dry conditions keep slugs from being abundant, but they are more likely to appear in larger numbers during wet springs and summers.
How They Impact Your Plants:
Do they crawl? Do they slither? Do they slide? No one really knows what to call it, but we do know that slugs move through repeating waves of muscular contractions, while secreting a layer of mucus to travel on. Ew.
Generally, slugs will crawl along the soil, up the stalk of a plant, and onto the leaves. They’ll eat both fresh and decaying vegetation, so when they decide to make a meal of your plant, they can eat fresh leaf material that the plant needs for its metabolic processes. A few bites won’t make a difference to the plant, but a significant amount of leaf-loss can lead to plant stress or death.
Identifying Slug Damage:
You’ll notice slug damage by the obvious, rounded-edge bite marks around spots that have been eaten away, and the unmistakeable shiny “slime marks” left behind.
How to Deal With Slugs:
Diatomaceous Earth: This powder is made from fossilized remains of diatoms (containing silica). It’s completely organic and food grade, making it 100% safe for edibles, pets and children. Just take care not to inhale the dust when you apply (you don’t want silica in your lungs!). D.E. causes micro-abrasions in the layering on the slugs body, which causes water loss, leading to fatal dehydration. Simply layer the powder along the soil, on the plant, and any other horizontal areas where the slugs may be eating or travelling. The powder must be visible to be working, so reapply after rain or heavy wind.
Beer trap: As a home remedy, the fermentation in beer is known for attracting slugs and makes a great bait. Use a plastic cup, and add about a half-inch of beer to the bottom. Dig a small hole and pack-in the cup so the open top is flush with the ground. Slugs will be attracted to the smell, and will fall in as they crawl over the cup. This remedy is easy, most people have the ingredients at home, and it works. But prepare to be grossed out! Someone’s got to deal with all those dead slugs. This remedy is also easily disrupted by the elements, so you may want to check out your traps regularly.
Safers Slug Bait: This is simply a poison that falsely attracts unsuspecting slugs, who eat it and quickly die. Though it’s quick and easy to use, this remedy isn’t pet or child friendly, and we recommend it as a last resort.