To some, slugs are minor nuisances that look less appealing than their shelled gastropod relatives. They may even spark a sort of curiosity as they plod along the path, leaving a meandering trail of slime. To others, however, they are troublesome pests with voracious appetites that can wreak havoc on the garden if left unchecked. If you notice small, rounded holes at the center of your foliage, instead of at the corners, then it is likely that you are dealing with a slug infestation. When attempting to get rid of them, refrain from using pesticides, as they can harm beneficial insects and other creatures that prey on slugs. Rather than trying to poison slugs using artificial products, try one of these natural and organic methods, which have been evaluated below based on their effectiveness.
Use Beer Traps
Although it sounds funny, one of the most popular methods is using a beer trap. You may think they are attracted to the alcohol, but they are actually attracted to the yeast inside the beer. If you have some leftover beer, set aside some to trap slugs. For increased potency, add yeast and sugar. Fill a shallow container with beer, bury it so that it is level with the ground, and wait for the slugs to climb inside and inevitably drown. You can also create a solution using water, baking yeast, and sugar. Note that they are only somewhat effective and should be used along with a combination of other methods. Some limitations are that they only work over a short distance and that they fail to catch a majority – most slugs will drink the beer and leave.
Use Raised Garden Beds
An effective slug barrier, such as a raised bed, can help deter slugs. While raised garden beds themselves do not prevent slugs from encroaching your crops, they make it easier to apply eco-friendly barriers to protect your plants from them. Vego Garden has a medley of metal raised garden beds in a variety of shapes and sizes that are suited for all kinds of planting endeavors. If you are dealing with a bothersome slug population, consider investing in modularly designed protective plant covers, which can protect young plants from the elements, as well as pests such as snails, slugs, and birds.
Copper, whether in mesh or strip form, has been commonly used to repel slugs, provided that it is wide enough for the entire slug. Though there have been some articles questioning the efficacy of this method, there are many gardeners that attest to its effectiveness. While there is no official explanation why it works, some attribute it to copper’s highly conducive properties, which carries an electrical current that shocks them. Others claim that copper is toxic and affects the slug’s internal physiology, limiting their slime production and ability to digest food. Whatever the reason, it is worth a try. Copper tape, which can be easily bought at Amazon, can be applied to the edges of your garden bed. Alternatively, you can attach a small mesh copper fence around the garden bed to secure your crops.
Encourage Natural Predators
If the concept of natural or wild-life friendly gardens appeals to you, you should take steps to invite wildlife that prey on slugs to the garden. Many bird species will eat slugs, including woodpeckers, blackbirds, and song thrushes, so consider installing a bird bath or bird house. Toads, turtles, praying mantises, beetles, and frogs have also been known to incorporate them into their diet. Be wary of attracting hedgehogs, as slugs are frequent carriers of roundworm, and can make them seriously ill if ingested.
Change the Environment
Slugs thrive in dark, damp environments, so the reasonable course of action would be to eliminate environments conducive to their growth and render them inhospitable. Known to eat almost anything, slugs will consume leaves, ripening fruits, and decaying plant matter. Reduce shady or weedy areas and clear the ground of leaves and debris. Using raised garden beds and compost will help improve drainage. Since mulch can retain moisture, get rid of large wood chips and any excess mulch.
Use Organic Slug Pellets
Unlike typical slug pellets, which contain a poisonous substance known as metaldehyde that can be lethal to wildlife, organic slug pellets contain iron, or ferric phosphate. Research has shown that methods using organic slug pellets have performed as well as synthetic controls, and are recommended for organic gardeners and the average gardener alike. Unfortunately, since ferric phosphate can also affect earthworms, which are beneficial for the soil, it is advised that you use it sparingly.
Plant Crops that Naturally Repel Slugs
If you find that there are some plants that are consistently being targeted, despite trying several methods, it is time to replace them to those that repel or are not particularly popular with slugs. They will often avoid full-sun plants or drought-resistant, native plants. Many aromatic herbs, such as rosemary and lavender, serve as great companion plants that will repel slugs. They are also averse to ferns, hydrangeas, ornamental grasses, and bleeding hearts. Consider growing sacrificial trap crops such as marigolds to lure away slugs and save important crops.
Use Coffee Grounds
While you may enjoy the pungent smell of coffee, slugs do not. Sprinkle coffee grounds around plants to create a slug resistant barrier – as well as provide natural fertilizer for the soil. You can also use freshly brewed, cooled coffee, and spray it around your plants, avoiding the leaves. In large doses, caffeine is said to be highly toxic to slugs; in small doses, it can slow them down. Because caffeine is the main agent, a strongly caffeinated coffee is more effective.
Pick Slugs by Hand
One of the easiest and simplest methods is to just pick the slugs by hand. They are most active at night during wet and humid weather, and can be found hidden under leaves where damage is present, rocks, or debris. After you discover them, drop them into soapy water. Even though it may seem disgusting, it can be a satisfying and relaxing process once you try it.
Methods to Avoid
- Slug Pellets – Slug pellets often contain metaldehyde, a toxic chemical that has been recently banned in the UK and poses a danger to both wildlife and pets. Instead, opt for organic slug pellets, as explained above.
- Salt – Salt has been recommended, as it will draw out the water inside their cells and dehydrate them in a process known as osmosis. When slugs are exposed to copious amounts of salt, they will quickly shrivel and dry out. However, this is not recommended as it can damage the nearby soil, or other places the slug can crawl on, such as the deck or patio.
- Eggshells – Another widely circulated myth is that sprinkling eggshells around the perimeter of plants will help deter slugs. The basic premise is that the serrated edges of eggshells will repel slugs, but several experiments have shown that they don’t mind eggshells and can easily cross the barrier.
- Diatomaceous Earth (DE) – Similar to salt, DE – which contains silica and fossilized microorganisms – acts as an irritant, cutting the insect’s skin. However, it shouldn’t be used as it loses its effectiveness when wet and can kill beneficial insects.
We hope you've enjoyed reading through and learned some a few ideas about how you can get rid of slugs in your garden to create a healthy environment for your garden! We know it can be challenging, but with persistence and dedicated care for your garden, you'll be on your way to having a beautiful, bug-free harvest in no time!