Slugs ~ 15 ways to deal with them organically

Slugs, slugs, slugs…. When we experience wet weather (which can seem like more than our fair share in Ireland), gardeners can be overwhelmed by slugs and snails. What’s the best solution to ridding our vegetable patches, gardens and borders of these slimy little creatures, without automatically reaching for the slug pellets? It’s the question I’m asked the most and everyone has their own answer.

However, before you start obliterating the garden of every last slug in sight, it’s important to know that not all of them are baddies that want to devour all our plants.

The green cellar slug (which we found with a mouth stuffed full of pizza one evening!) like to hang out on compost heaps and also enjoy a diet of mould and algae. The John Innes Centre have a page highlighting the most common in the UK (which often live in Ireland too) helping to identify slugs, and I’d recommend you take a peek.

Once you’ve established whether you’re looking at a Brown Field slug or a Budapest Keeled, what can you do to about them?

From beer to salt, copper to egg shell’s, I’ve heard lots of tips and advice over the years. Here are the most common fifteen:

No. 1 – Encourage predators

Birds, frogs, toads, Devils coach-horse beetles and hedgehogs all like to snack on slugs. Ducks and some hens enjoy snacking on them too, if you’re lucky enough to have them. Turning over soil will expose the slugs to birds in dry weather.  If you let your poultry roam the  garden but are worried about your seedlings and plants, covering the soil with horticultural fleece should be enough of a deterrent to keep them away.

No. 2 – Beer traps

Bury shallow plastic containers around your garden (take away containers are the ideal size) and sacrifice a drop of your favourite brew. If you can’t bear to give up your drink, pubs may give you something from the slop bucket if you ask nicely. Be careful not to fully bury the container though – leave a small ‘lip’ above the soil level so that beneficial beetles don’t fall in and drown. Alternatively pour some beer into a spray bottle and spray all the weeds. As the slugs like the beer so much the idea here is that they’ll eat the weeds, leaving your veggies alone. You’d have to question whether you want your garden to smell like a brewery though.

No. 3 – Egg shells

I’ve tried these and I personally didn’t notice a difference. However, egg shells are good for our soil given their calcium content so might be worth a try. Always wash egg shells first prior to this, (or adding to your compost come to that) as they can attract rodents. Collect and wash egg shells then heat in the oven to harden them. Put the egg shells in a food processor and blitz until small, then place a protective ring around seedlings. A friend swears by this! You could also use sawdust, sand or seaweed – all of which are might to hinder the slugs movements.

No. 4 – Copper

Mr G spent ages stripping the copper out of some old electrical wire a few years back, patiently stapled it around the raised beds and placed a slug in pole position to test out the theory that slugs don’t like copper. The slug smooched his way over the wire and straight into the veggie bed. The trick with the copper is to use lots – thick bands can be purchased at garden centres, or even better if your budget will allow, buy copper tools that discard tiny pieces into the soil.

No. 5 – Traps

If you don’t like to kill creatures of any description you can trap slugs safely. Cover an area with cardboard or black plastic before sowing. The slugs will all hide under it so that when you expose them a few days later you can pick them off. Slugs also like grapefruit so leave halved and emptied shells lying around (dome side up) with little doorways cut into them. The slugs will head into them, hiding away until you can  collect them up and add them to the compost heap.

No. 6 – Instant Death

If you prefer to permanently get rid of slugs the most humane method is to cut them in half causing instant death. It’s strange how we might feel squeamish about that, yet are ready to kill them by less hands on methods that might cause them pain. Other methods are putting boiling water into an empty milk carton, picking up the slugs and dropping them in. I’ve read that after a few days this foul-smelling solution can be watered onto soil which will detract other slugs from venturing onto it, but have yet to try it. I guess when you’ve seen slugs wipe out your entire seed collection the war is on.

Green Cellar Slug

No. 7 – Microscopic nematodes

‘Phasmarhabditis hermaphrodite’ also known as NemaSlug are available online that can be watered onto plants. They’re supposed to be very effective but the downside is that they’re quite pricey and will have to be re-applied after six weeks or so.

No. 8 – Iron based phosphate slug pellets

Slug and snail ultra pellets contain ferric phosphate which occurs naturally in the environment and are approved for organic production. They are safe for pets, birds, hedgehogs, bees and other common garden creatures. The little blue pellets

Regular slug pellets are usually made from poisoned cereals containing Metaldehyde or Methiocarb which (because they are food based) are also attractive to cats, dogs, birds and hedgehogs.

No. 9 – Caffeine

Slugs and snails do not like coffee. Sprinkling coffee grounds around plant bases will act as a repellent, as does filling a spray with cold, strong coffee and spraying slugs. That said, coffee grinds are best added to the compost heap as their slow release nutrients will help to improve the soil in the heap.

Slug Damaged Bean

No. 10 – Barrier Method: Bran or Seaweed Meal or Dust

This came out tops in a Gardeners World trial a few years ago. They placed a ring of bran (available in health shops) around each plant ensuring it didn’t touch the stems. As slugs are almost entirely made up of water, the bran had a desiccating effect which killed them. Salt would have a similar effect but as its toxic to all but a few salt tolerant creatures and plants, and not good for the soil it isn’t recommended.

In recent years I’ve been using seaweed meal which has been very effective. I’ve sprinkled it around the raised bed as an initial deterrent, and then added a circle around each seedling (keeping it away from the stem) for an additional barrier. Seaweed contains a naturally balanced range of minerals, trace elements, amino acids and vitamins which are great for soil microorganisms. You can also add it to your pet or animal feed as a supplement, but given its saltiness, it’s not a slug’s food of choice and they tend to avoid it.

No. 11 – Planting flowers and herbs

Some plants are known to repel slugs so placing plants such as Astrantia, Lady’s Mantle, Dianthus, Foxglove, Geranium, Peony, Lavender, Phlox, Alyssum and Lobelia, African violet, Strawberry Begonia and Gloxinia may help. It’s unlikely that anybody with a standard vegetable patch/allotment arrangement would go to this trouble but may be worth trying some. I can’t help but think how lovely a lavender hedge around my patch would look and smell though, and attract lots of bees and hoverflies in too.

Slug Protection

No. 12 – Start seedlings off indoors 

Once they’re a decent size of around 10cm or so in height, transplant them outside. If you’re unable to do this, place a cut-in-half clear drink bottle around seeds/seedlings until they’re bigger and stronger (leave the lid off to allow for ventilation.

No. 13 – Watering

Slugs prefer dark, damp conditions so if they are a problem in your garden or polytunnel, avoid watering in the evenings.

No. 14 – Diatomaceous earth

Diatomaceous earth is a naturally occurring compound approved for organic use and has many benefits for plants, animals and humans.

As a pest control, Diatomaceous earth isn’t as finely milled and its microscopic sharp edges can cut through and dry them out. It can be useful for slugs, caterpillars, ticks, vine weevils, flea beetles and maggots. It’s important to wear a dusk mask when applying so you don’t inhale it. Simply sprinkle onto plants after a light rain or in the morning when plants are still wet from dew. It can also be applied wet.

No. 15 – Garlic

Slugs don’t like the smell so you could try crushing a clove and adding it to the watering can, sprinkling the mixture over areas worse affected to prevent them nibbling.

Have you any sure-fire tips for saving your vegetables from slugs? Have any of these worked for you?