Years ago, I learned that trying to eradicate troublesome wild things in a garden is seldom possible in the long term-and sometimes not even wise. For instance, yellow-jacket wasps disrupt outdoor meals but also feed on caterpillars and insects.
Slugs have the same dual character. They arouse our hatred when they eat precious seedlings, but also recycle dead plant materials and become food themselves for garter snakes, frogs, toads and some birds, including starlings and crows. Since they're prolific breeders, controlling their damage is the most reasonable goal.
Most at risk are tiny seedlings during their first few weeks. This is when one or two hungry slugs can destroy a whole crop in one night, especially if it's been planted in a straight line. That's why organic gardeners sometimes dot susceptible crops in groups over several different garden beds.
One of my favourite protections is sticky copper tape. Circling a band around a container of seedlings is effective protection, while for garden seedlings bottomless plastic containers banded around with copper tape can be popped over susceptible plants. But I've found copper barriers most effective when new and shiny. It's best taken out of the garden when unneeded and stored in a dry place to use for the next batch of seedlings.
Fence type copper barriers need frequent checking. Rain can open tunnels underneath while leaves of taller plants may form bridges over the top. Also, some slugs may be hiding in the soil when you install your copper fence.
Polycarbonate juice containers, bottomless, with the tops removed and plastic mesh covering the opening make great slug protection when they're pushed into the earth and are a mini-greenhouse at the same time. Plastic soft drink bottles also work, but are lighter, smaller and more susceptible to wind.
Slug-deterring substances include crushed eggshells, coffee grounds, grit, garlic and perlite (none of which worked for me). Diatomaceous earth seemed to do better, but needs care to avoid inhaling it. Lime is reputed to work, but must be redone if it rains.
Sneaky tricks for slugs include slug saloons with beer in which slugs blissfully drown. These need to be cleaned out each day if you want to avoid a truly disgusting experience. Some gardeners put out planks or grapefruit halves where slugs hide, then are discovered and destroyed.
The top slug predators are ducks, especially the dryland Indian Runners. But desperate gardeners who've lost precious plants to slugs are likely second on the predator list. Their weapons may include non-toxic ferrous iron slug bait, salting or ammonia spray. But learning slug habits encourages gentler methods. Watering at night is like a party invitation to a slug. They tend to be territorial going back to the same feeding zone every night. But they don't usually travel more than 100 feet for a meal, which gives gardeners an idea how far to trap-and-release them.
Slugs are hermaphrodites who mate, but can also be self-fertile. The result can be 300 eggs a year, usually laid in groups of 10 to 20. Chickens enjoy eating slug eggs.
Just one slug is worth welcoming into your garden: that's the native black-and-yellow banana slug, a strikingly beautiful forest dweller whose main food is mushrooms.
