Buzz
Slugs are a menace to gardeners; these small gastropods often sneak out at night, devouring leaves and fruits on plants. Instead of letting them take over your beloved garden, take action to eliminate the slugs that are damaging your plants. With a variety of methods including baiting, trapping, and using natural predators to remove slugs, you can keep these pests at bay. Note that all these methods also work for snails.
Steps
Set Traps and Hunt
Use beer or alcohol traps for important plants. Slugs are only attracted to traps within about a meter of their location, making this method most effective for small gardens or key areas. Set up traps as follows:
- Bury a tall cup with a sloping interior in the soil. Leave about 1 cm of the rim above ground to prevent beetles that hunt slugs from falling in.
- Fill the cup halfway with beer or milk.
- Replace the cup every few days. If slugs escape, switch to a mixture of honey, yeast, and a bit of water, boiled until sticky.
Eliminate slugs using traps with coarse cornmeal. Coarse cornmeal is inexpensive but may not attract many slugs. Place 10 to 20 grams of cornmeal in a jar and lay it horizontally. Keep the cornmeal dry, and it will kill slugs by expanding inside them.
Lure slugs with humane traps. Slugs gather in dark, damp places, such as under wooden boards, flower pots, or cardboard boxes. Set traps and check daily to collect and remove them far from your home. For best results, bait them with one of the following slug foods:
- Cabbage leaves
- Citrus peels soaked in water
- Dry pet food
Protect traps from rain and pets. Water can ruin cornmeal and liquid traps. Place a cover above to shield them from rain. If you have pets that might eat the bait, use protective covers like an upside-down flower pot with a small entrance.
Hunt slugs at night. While not the most enjoyable task, hunting slugs individually may be necessary for severe infestations. Use a flashlight and gloves, skewer slugs with a stick, or drop them into a bucket of soapy water. A headlamp makes the task easier.
- Check under leaves.
- Follow slime trails you spot.
Preventing Slugs
Keep the garden dry. While results may not be immediate, maintaining a dry garden is the best long-term strategy for slug control. Here are some tactics to make your garden less inviting to moisture-loving pests:
- Water plants mid-morning so the soil dries before nightfall.
- Install a drip irrigation system to minimize water usage.
- Keep the yard free of debris and mow the lawn regularly.
- Avoid organic mulches like straw or grass clippings.
- Space plants adequately to allow air circulation.
Use mulch or tea from specific plants. Preparing the following plants can deter slugs to some extent, if available at your local garden store:
- Oak leaf mulch or tobacco stem powder, spread as a barrier around plants.
- Wormwood tea, made by steeping wormwood branches in warm water for 24 hours. Strain and mix with soapy water, then spray on soil or slugs.
Create barriers with copper strips. Purchase copper strips wide enough to prevent slugs from crawling over. Use them to form barriers around plants or garden beds.
- Note: These strips can cause cuts, so handle with care, especially around children.
Sprinkle salt on non-soil surfaces. Apply salt to areas where slugs frequently crawl to kill them via the moisture trails they leave. Be cautious, as salt can harm plants and soil. Use it around patio planters or place barriers on the ground before salting to protect soil quality.
- Avoid using salt where it may dissolve in water (e.g., during rain or irrigation). Water can wash salt into the soil, damaging its quality.
Set up barriers using traditional methods. Gardeners have tried various home remedies to deter slugs. Below are some effective options, though they may not eliminate slugs entirely:
- Coffee grounds may have a mild impact on garden health.
- Coarse sand can scratch slugs but may not fully stop them.
- Seaweed is less effective than salt but safer for soil. Calcium-rich seaweed is preferable if available.
Plant varieties that deter slugs. Certain plants naturally repel slugs due to their taste, texture, or toxicity. Plant them as a barrier around your garden or intersperse them with other plants. While these plants won't eliminate slugs entirely, they can significantly reduce their presence without much effort. Consider the following options:
- Herbs: ginger, garlic, aromatic herbs, mint, and chicory.
- Vegetables: bitter-tasting vegetables are less appealing to slugs than sweet ones. Try kale, spring cabbage, or broccoli sprouts.
- Blue-leaved hosta varieties are particularly effective.
- Shade-loving flowers: Astilbe, Dicentra, Digitalis (foxglove), Lobelia, Viola (some pansies and violets). Also, Ranunculus (buttercup) and Vinca, though they grow rapidly.
- Partial shade flowers: Oleander, bellflowers, daylilies. Additionally, European pennyroyal, which grows quickly.
Consider stronger (but riskier) barriers. Several materials can kill slugs on contact and serve as effective barriers to their movement. However, they must be used cautiously and kept dry. Misuse can harm your garden, pets, or even people. Ensure these materials are applied to surfaces without soil, except as noted:
- Safety warning: Avoid inhaling or handling these substances without gloves. They may not be suitable for gardens frequented by children or pets.
- Diatomaceous earth: May harm beneficial insects.
- Wood ash: Increases soil pH, offering high effectiveness.
- Hydrated lime: Significantly raises soil pH and may render soil unsuitable for planting.
- 1% caffeine spray: Apply directly to plants you wish to protect; kills slugs when ingested. May unpredictably affect plant health.
Utilize Natural Predators
Introduce ground beetles. Ground beetles are natural slug predators. You can purchase beetle larvae from garden stores and scatter them around your garden in early spring. The larvae will feed, pupate, and emerge as adults by summer.
- Encourage wild beetles to settle near your plants by providing shelter under rocks, grass, or straw. This helps them evade predators and makes your garden an attractive habitat. Fortunately, ground beetles thrive in most areas where slugs are found.
Use birds for effective control. Birds are the largest natural predators of slugs. Ducks, chickens, robins, jays, and other common birds relish slugs as a meal. If you don't mind handling them, you can collect slugs and toss them to wild birds in the morning. Over time, birds will associate your garden with a food source and hunt slugs independently. If you keep chickens or ducks, you can also feed them garden slugs daily.
- Monitor chickens closely, as they may also eat plants.
- Encourage birds to nest in your garden by creating dense hedges, providing food, and setting up bird feeders.
Release toads. Toads are natural predators of slugs and other harmful garden pests. To attract wild toads, place overturned pots or containers with a rock underneath to create a dark shelter. Alternatively, you can purchase wild toads to keep in your garden, where they will help control the slug population. Adding a small decorative pond can also encourage toads and frogs to settle in your garden.
- Avoid keeping fish in the pond, as they may eat tadpoles.
Introduce nematodes if necessary. Nematodes are microscopic parasitic worms that live in soil. You can purchase specific nematode species designed to target slugs from local garden stores. While highly effective, this method has a downside. Once all slugs are eliminated, the nematodes will either leave or die off. Without regular reintroduction every few weeks, a new wave of slugs may invade and dominate the garden due to the absence of natural threats.
- Follow instructions carefully when using nematodes. Typically, they are spread on the soil and then watered in.
Use Chemical Solutions
Spray ammonia on slugs. Create a homemade slug spray by mixing ammonia with water. Combine 1 part raw household ammonia with 6 parts water. Pour the mixture into a spray bottle and apply it directly to slugs whenever you spot them. Be cautious not to spray plants directly, as it may burn their leaves over time.
Use iron phosphate pellets. These small slug-killing pellets are available at garden centers and can be scattered around your garden. Slugs are attracted to them but will die within a week of consumption. This method is safe for most pets and edible plants, though it’s best used sparingly.
- Look for brands like Sluggo, Slug Magic, and Escar-Go.
Using metaldehyde. Metaldehyde is a widely used slug killer, but it comes with certain limitations. Notably, metaldehyde can be highly toxic (especially to dogs). Proper handling and placement of traps are crucial to avoid endangering household pets.
- Avoid using metaldehyde "pellets," as they can be mistaken for pet food. Instead, opt for "granules."
- Store metaldehyde in a place inaccessible to dogs.
- Do not use this method near edible plants.
- Spread metaldehyde thinly; avoid piling it up, as pets might mistake it for food.
- Metaldehyde works best on dry, warm days but should not be used under direct sunlight. Apply it beneath leaves in the evening before warm weather is forecasted.
- Look for products with low-dose metaldehyde, which are less harmful to the environment.
Advice
- Spray WD40 around the base of pots on your porch, covering about 5-7 cm on the top surface. It will last a long time, even during the rainy season. Do this twice a year.
- If handpicking slugs, hunt them at dusk, preferably on damp nights, or catch them early in the morning.
- Try trapping slugs with peanut butter covered in salt.
Warning
- There is some debate over whether iron phosphate pellets truly contain toxic ingredients. It is believed they contain EDTA, a substance listed as inert.
- Many slug traps are marketed as safe, containing no toxins that harm or kill invertebrates, including worms.
- Slugs are mollusks, not insects, so conventional insecticides will not work on them.
