I may receive commissions from purchases made through links in this article. But that in no way influences my opinions.Full Disclosure
Slugs are an absolute nightmare in the vegetable garden. They’re bad enough in your ornamental garden, but among your fruit and vegetable plants, these little mollusks are the gardener’s nemeses. The rasp away at your plants and can devour entire crops in short order. Young, tender seedlings are often the victims of the insatiable appetite of an army of invading slugs. Slimy and cunning, slugs are a pain in the behind and oftentimes it feels as though they’re unstoppable. Many of us then reach for the chemical-laden toxic slug killer. The trouble is, that stuff is lethal to insects, including the beneficial ones, not to mention useful wildlife like foxes, frogs, toads, and hedgehogs. And then there’s the danger to your pets and livestock. Plus, the last thing you should be doing, if you’re growing your own food at least in part for health reasons, is putting dangerous chemicals into your soil, which then leach their way into your plants that you then proceed to eat. Gross. And potentially dangerous. And, if you’re going down that route, you may as well save yourself the time and energy and just go buy the chemical-infused over-priced produce from the grocery store.
You do actually have a number of less dangerous options. There are numerous ways to control slugs naturally. However, like with many natural alternatives, you may have to implement a couple of methods simultaneously for real success.
1. Choose Watering Time Carefully
Slugs are more active at dusk and after dark, and their preferred conditions are damp and dark. Therefore, one effective approach to controlling slugs naturally is to water early in the morning rather than in the afternoon or evening. In hot weather, remember to water as early in the day as possible to avoid burning tender leaves. While this simple approach doesn’t deter or kill slugs, it makes sure your plants are as unappealing as possible and doesn’t encourage those nightmarish mollusks or gastropods.
2. Companion Planting for Distraction
Slugs and snails aren’t the brightest of creatures and they are easily distracted. The key is to choose companions that are expendable and that the slugs want more than the crops you’re trying to protect. A great choice of companion plant is lamb’s lettuce. It grows vigorously and slugs adore it. Yes, it feels horrifically wasteful to deliberately plant lettuce for the benefit of the slugs, but it pays off. A strip of loose leaf lettuces strategically placed to draw slugs helps the rest of your crops survive the slug and snail onslaught relatively unscathed. In the grand scheme of things, given how hardy and inexpensive loose leaf lettuce varieties are, it’s a fairly small sacrifice.
Red clover is another spectacular choice. It acts as a decoy and draws slugs. In multiple studies, researchers have found that red clover proves the most effective decoy or companion plant to attract pests like slugs. Aside from the fact that slugs just can’t resist it, red clover is nitrogen-rich and turns into valuable, nutrient-rich organic matter as its growing cycle ends.
During spring, when many of your food crops are at their most tender and vulnerable stage, slugs attack without mercy. Lawn chamomile is invaluable during this period. This hardy little cover crop is already growing vigorously in spring and proves irresistible to slugs. It will help draw the slugs away for a feeding frenzy, helping keep your young crops safe.
3. Go Slug Hunting After Dark
Slugs, although they are nomadic, tend to come back to the same place over and over, so if they make it to your garden, they’ll keep on coming back. One sure-fire way of controlling slugs naturally is to get rid of them by hand. Wait until after dusk or, if you’re an early riser, dawn also works. You’ll have even more luck if it’s damp, is, or has recently been raining. Get yourself a flashlight and some rubber gloves or some tweezers and a jar of soapy water and go slug hunting. It’s pretty brutal, but it works. Use slug hunting in conjunction with other natural pest control methods on a regular basis to significantly reduce the numbers of slugs attacking your veggies.
4. Encourage Predatory Beetles
While there are any number of predatory beetles that enjoy chowing down on slugs, carob beetles are among the most effective. They prey on young slugs and eggs. These nocturnal predators happily hunt slugs and their eggs all night long. Just make sure you provide a suitable habitat to encourage them. Make a beetle bank if you have lots of space or, if you’re homesteading or growing food on a smaller scale, plant tough grasses between beds, make a beetle box or a wild area. If you provide them with the right home, these predatory beetles will significantly reduce the numbers of slugs attacking your food crops.
5. Ducks and Chickens
Ducks and chickens are so useful if you grow food. Yes, they produce delicious eggs, but they have plenty of other uses, too. Their poop makes nutrient-rich fertilizer and they love nothing more than snacking on slugs and snails. Just remember not to give them free reign in your vegetable plot, as they’ll eat your plants, too. A good option is to let them run and scratch and eat on fallow patches or between beds, or anywhere slugs are likely to hide where your cultivated plants aren’t. They’ll clear weeds in these areas, which reduces hiding places, as well as eating the slugs themselves.
If you’re lucky enough to live in a part of the word where there are wild hedgehogs, encouraging them into your food garden is one of the most effective ways of controlling slugs naturally. These tiny carnivores devour every slug and snails they find, and they consume large quantities every night. Entice them with rotting log piles, “wild” patches that you don’t disturb, and plenty of hidey holes. Some hedgehog rescues may also consider allowing you to adopt hedgehogs that can’t be released back into the wild, as long as you can provide a secure, enclosed environment, and food in the absence of adequate wild food sources.
7. Frogs and Toads
Frogs and toads voraciously eat slugs, so, if you have a water source, or are close to a water source, do what you can to encourage them. Remember, however, that some duck species eat frogs as gleefully as they eat pests, so try not to mix these two natural slug control solutions.
Using nematodes is actually pretty controversial. A single course of nematodes only lasts for around six weeks. Using nematodes is a natural or biological way to control slugs, but it’s comparatively costly and it’s actually too effective. Too effective? Sounds crazy, right? The problem is that the nematodes are so good at eradicating slugs that they unbalance the local ecosystem. Suddenly, there are no slugs at all, so the predators that hunt slugs all move away. Six weeks pass, and there are no more nematodes. So then you’ve got an area rich in food with no predators. You’ll then find you’ve got a ravenous slug plague on your hands. And it’ll be much worse than before you purchased the nematodes. You’ll then struggle to regain control until enough predators move back into the area. Or you’ll be forced to repeatedly release nematodes every six weeks, which can prove costly if you’ve got a large area to cover.
If you do choose to release nematodes, here’s what you need to know about them:
Nematodes are microscopic parasitic worms. They work in symbiosis with a special bacteria that acts as a food source. You take your nematodes and water them onto the soil. Once released, they actively hunt for a host. Finding a host, the nematodes infest it. The bacteria is released and the nematodes start to feed and multiply. The infected slug stops feeding within three to five days as it begins to swell. Overwhelmed, the slug dies and, as it decomposes and splits open, the next generation of nematodes flood out of the body and start their hunt for new victims. It’s pretty gruesome – but it is effective. Just remember, you could easily be making a rod for your own back if you choose this route.
9. Get Them Drunk
Slugs can’t resist beer, ale, and Guinness. It doesn’t even have to be the good stuff. A cheap bottle, flat leftovers, the dregs from another bottle. Any beer will do. Place a good few inches in a jar, a plastic bottle, or a disposable cup, and sink it into the ground around the perimeter of your crops. On their way to chomp on your veggies, the slugs make a detour for the beer and, once they’re in, they quickly become too drunk to climb out and they drown. We do, however, strongly suggest putting a twig in the container at a gradient so that insects can climb out if they accidentally fall in. The slugs, I hasten to add, cannot make it back up the stick once they’re in the beer. Just make sure there’s enough liquid in there to drown them.
Rain-proof slug beer trap:
Just bury this around half way down for stability and to help the slugs find their way inside. You’ll find that it’ll get even more effective as slugs start to decompose and ferment. Yes, it’s gross. But it works. Once you’ve got a thick, sludgy mess or it gets too diluted, empty out and start over.
10. Other Drowning Methods
Using the same bottle and twig construction, you can use a host of other liquids to attracts and drown slugs. Try a mixture of honey and water or yeast, sugar, and water.
11. Copper Borders
Copper sounds like an odd way to deter slugs – but it works. For some unknown reason, slugs don’t like to crawl over it. Copper coins work – and can do in a pinch if you need to rapidly form a border around a vulnerable plant – but it isn’t an effective long-term solution – because it’s costly. You can buy copper garden strips, but again, this is costly on a large scale. So, get your hands on some old copper cable and strip off the plastic insulation. Then you need to get a little creative. For example, if you’ve got problems with slugs attacking your seedlings still in your greenhouse or on your potting bench, remove all the slugs, remembering to check the bottom of pots and between plugs in trays. Make sure that your plant staging or potting bench isn’t resting against any walls, then wrap copper around each leg. Put two or three loops around each leg for the best results. Slug-proof seedlings. For plants outdoors, you can protect particularly vulnerable ones by wrapping copper around an empty plastic bottle with the top and bottom cut off, then place this over the seedling. Just remember that if you’re using a stake to support the seedling, wrap copper around that, too. When the copper gets dirty, give it a clean with a little vinegar.
12. Eggshell Borders
Eggshells are a great short-term measure. Slugs won’t cross the sharp edges. However, as soon as they get muddy or wet, they become less effective. And, with exposure to the elements, the sharp edges quickly become dull. However, eggshells are great for the soil, so it doesn’t hurt to just keep replenishing the eggshells with fresh ones in small areas.
13. Other Borders
There are a range of other items you can try that some people swear by. These include:
- Nut shells
- Diatomaceous earth
- Charcoal dust
- Lava rock
- Wood ash
But, like eggshells, many of these methods lose effectiveness when wet. Try a few different methods and see what works best for your garden.
Centipedes are by no means pretty – but they are well-equipped to help you control slugs naturally. These nocturnal predators are effective slug killers and devour large numbers. It’s important to note that there are numerous distinctions between millipedes and centipedes – the primary one being that millipedes are herbivores and will eat your plants. So be sure you can spot the difference. One key indicator is that millipedes have round bodies with two pairs of legs per segment, while centipedes have flat, segmented bodies with only one pair of legs per segment.
Having centipedes in your garden is hugely beneficial as they will eat any number of pests, including slugs and snails. You can attract them by creating a habitat that’s suited to them. They live among rotted leaves, rotting wood, under rocks, and some species burrow into the ground.
Do bear in mind that some species of centipede can deliver a nasty bite to humans. While these bites aren’t fatal, they hurt considerably, so we strongly avoid provoking or handling them.
Slugs aren’t the brightest creatures, so it’s easy to lure them into traps. All you need is to create a small covered, dark, damp area. For example, grapefruit halves work well, as do overturned pots with damp cardboard underneath. Give these pests somewhere to get comfortable during the warm daylight hours. Then go and murder them at your leisure.
There you have it – 15 natural ways to control slugs. Remember, you’ll most likely have to adopt several methods to gain real control, but it’s worth it. Aim for a balanced ecosystem with plenty of food for predators to keep them coming back. Ideally, leave the small slugs and snails and start by removing the bigger ones. This ensures there’s enough food for the predators while you’re eliminating as many of the big ones as you can find.
Don’t forget to sign up to our newsletter and claim your free copy of 1 Week to a Greener You.