Slugs may be an essential component of many ecosystems, but they can also be the bane of every gardener’s existence. Widespread around the world and impossible to eradicate, slugs will eat through seedlings and shoots of all sorts of plants. Thankfully, there are ways to kill slugs in your garden or allotment which will notdamage your plants, the water or the rest of the environment.
Nematodes are a type of worm which will hunt slugs, infect them with fatal bacteria and reproduce on their bodies, but will leave any other animal alone. They are most effective when the soil is moist and warm—around 41 to 68 degrees Fahrenheit—so you should apply them in the spring, summer and early fall.Nematodes are now widely available to buy from specialized retailers and garden stores, and you can find quite a lot of information online about which nematodes to buy and how to use them.
2. Other wildlife
Nematodes are not the only animal that kills slugs—some birds, frogs, hedgehogs, toads, worms and ground beetles eat slugs, so it would be a good idea for you to configure your garden in a way which attracts these animals. According to the Royal Horticultural Society, the single easiest way to attract wildlife to a garden is to install a pond, even a tiny one. There are plenty of blogs to help you figure out where and how to dig your pond.Avoid the temptation to add fish to your pond, as they will eat a lot of the wildlife your pond attracts, and make sure that your pond is shallow and has a sloping side to allow frogs, toads and other amphibians an easy way in an out. If you lack the space or money to dig out a ‘proper’ pond, even an inverted trashcan lid will do the trick!
Another way to attract wildlife to your garden, particularly birds, bees and butterflies, is to grow the right kind of plants. Australian seed retailer Happy Valley Seeds, at www.happyvalleyseeds.com.au, suggest growing millet, which is a fast-growing and high-yielding cereal; you can then harvest its seeds and put them in a bird feeder to attract birds all year round.Do not just rely on millet, however: the best way to attract lots of wildlife is to grow a mixture of plants, particularly fruit trees and berry bushes—which have the added advantage of providing you with crops for your own enjoyment!
Avoid citrus trees, though, as these are particularly appetizing to slugs, according to the University of California Division of Agriculture and Natural Resources (you can read more advice from them at www.ipm.ucanr.edu).
There are snail and slug traps you can buyfrom garden or pest control stores, or you can make your own. To do this, according toSustainable Gardening Australia,take half of a round citrus fruit—such as an orange, a lemon or a grapefruit—and leave it in your garden overnight with the open end down. You can also use inverted flower pots for this, although you should make sure you do not clean them too well, as you will need something appetizing in there to attract the slugs. Remember to scrape the slugs off in the morning!
Strange as it may sound, sprinkling coffee around your garden is an effective way to repel slugs and snails, says coffee expert Kate MacDonnell.According to a study by the U.S. Department of Agriculture, solutions containing 1 to 2 percent caffeine will kill slugs and snails, and weaker solutions will act as repellents and send the slugs elsewhere. For reference, instant coffee usually contains around 0.05 percent caffeine, whereas brewed coffee can contain anything from 0.8 to 2.8 percent caffeine, so unfortunately a cheap instant coffee is unlikely to work well!
Another consideration to keep in mind is that although coffee grounds can work as a repellent, pouring coffee itself into the soil is more effective. If you are not prepared to brew a perfectly good cup of strong coffee just to pour it out into your garden, you could keep a spare cup on your counter and fill it up with the dregs of your coffees throughout the day. You could also use any coffee which you end up not finishing because of something else demanding your attention—if you are a parent, you will be familiar with this problem!
The best places to sprinkle your coffee are those where slugs like to hide, such as patches of tall grass and rotting logs, as well as around the plants you want to protect. Remember, however, that not all plants will do well with the highly acidic content of coffee—roses, azaleas, blueberries and holly are among the kinds of plants which will benefit from coffee, while tomatoes, clover and alfalfa will not. Keep in mind, also, that different types of soil have different base levels of acidity, and that you should not add coffee to an already very acidic garden—you can get a test done by an expert, or even find out how to perform one yourself.
Another great way to repel slugs is to create physical barriers around the plants which you would like to protect. This is where your coffee grounds can come in handy, as slugs don’t like crawling on them because of their abrasiveness. Other barriers you can try include crushed eggshells, wood ash, wood shavings and using lime juice.
Another popular method of repelling slugs is surrounding the plants you want to protect with copper tape or copper mesh, as copper supposedly interacts negatively with the slime produced by slugs and snails, although there is no consensus in the gardening community about whether this method is actually effective. Keep in mind that copper also repels birds, says Pest Insider, so you should not use it if you are trying to attract more birds to your garden.