Pest Control

By Eric Christensen

July 18, 2013 5 min read

Slugs are a perennial problem for home gardeners, and they are especially troublesome after a cool, wet spring.

Preferring cool, moist hiding places during the day, slugs emerge at night to feast on a variety of plant matter. They will attack foliage, flowers, fruit, young plant bark and seedlings. In the morning, they will retreat, leaving behind plant damage and a silvery slime trail. If evidence of a slug infestation is found, there is no need to call an exterminator. Slugs can be beaten with a variety of items, many of which are common household goods.

The first step toward getting rid of slugs is to eliminate those cool, moist hiding places. Keep the garden and the surrounding area free of fallen leaves, prunings and stacked boards or rocks. Tie up plants so that no leaves or fruit touch the ground. To reduce excess moisture around plants, use drip irrigation or soaker lines, or use sprinklers during the day so that the moisture has time to evaporate.

The most effective method of slug removal is also the most labor-intensive: handpicking. Using a flashlight, inspect the garden at night or just before dawn. Collect slugs in a bucket containing soapy water or 5-10 percent ammonia solution. The drowned slugs can be composted.

If late-night handpicking seems unappealing, prop up small boards about an inch off of moistened soil. In the morning, tip over the boards and collect the hiding slugs. If boards are unavailable, use upside-down ceramic flowerpots or citrus rinds. After a few consecutive nights of handpicking, the task can be done on a weekly basis.

Next, set up a variety of barriers to prevent the slugs' return. Multiple barriers should form a more robust defense against slugs, so long as no branches, leaves or plants bridge them, allowing slugs back in. After all, slugs trapped inside the barrier will be free to damage plants.

Seed the garden's perimeter using plants slugs dislike. This can include species with red leaves, such a Swiss chard, or ones with stiff leaves and strongly scented foliage, such as lavender, rosemary and sage. Gardeners have also found that begonias, geraniums, impatiens and nasturtiums resist slug damage.

Another barrier tool found in most gardening supply stores is copper strips or tape. Copper strips can be placed around the garden's perimeter, or small strips of sheeting can be wrapped around individual plants. The mucous-covered bellies of slugs do not react well to the electrostatic charge that builds up in the exposed copper.

Barriers that are dry, rough and sharp are difficult for slugs to cross, making them very effective. Sand, crushed eggshells, lime, crushed lava rocks or diatomaceous earth can be poured in bands at least an inch thick around your plants. However, these will need to be replaced after every rain. Although slugs will also not cross a barrier of salt, adding salt to your soil can harm plants.

Materials such a coffee grounds or pine needles also make effective barriers because they increase the acidity of the soil, and slugs prefer an alkaline environment. Not only will coffee grounds repel slugs, but they also provide nitrogen to your soil. Additionally, most coffee shops give away coffee grounds to gardeners.

In addition to barriers, consider slug traps. Bury cans or cups so that the lip of the trap is level with the soil. Fill the trap three-quarters of the way with beer or a solution of water, 1 tablespoon of sugar and 1/2 teaspoon of yeast. Slugs will find the scent of fermentation irresistible, crawl in and drown. Reset and refill your traps every few days after composting full traps.

Lastly, pellets of slug poison can be purchased at a gardening supply store and sprinkled throughout the garden. Look for nontoxic pellets, in case of accidental ingestion by children or pets.

Gardeners may never win the war on slugs, but you can limit the damage they cause with a little effort, a little vigilance and common household goods. If you see the signs of slugs, take action, and protect your produce. Better you reap the rewards of your garden, instead of a slug.

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