Are Slugs Good For Plants & Garden? (Expert Advice)

Are Slugs Good For Plants & Gardens?

​Most gardeners have made up their minds: slugs have to go. But are these destructive pests all bad? Let’s find out!

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Pros of Having Slugs in Your Garden 

Despite what many people believe, there are some positives to having slugs in your garden.

For example, they’re decomposers. They clean up dead plant material and other garden debris, so you don’t have to! 

Some of the larger slugs mostly eat only decomposing organic matter, making them a valuable addition to your garden.

This is especially true if you’ve got dead leaves lying around or a load of organic matter in your compost heap that needs churning down!

Slugs also fertilise your garden for free!

Their faeces are rich in nitrogen, calcium, phosphorus and potassium, which will seep into your soil and act as a natural fertiliser. 

Furthermore, slug predators love them! 

Slugs are a great food source for various lovable garden creatures, such as frogs, hedgehogs, and domestic animals like ducks and geese. 

Bird species such as robins, blackbirds, and thrushes also serve as excellent slug hunters, particularly if you lure them in with other attractions such as a birdbath or feeder. 

And finally, slugs can provide insights into your garden’s health.

Slugs prefer higher-humidity environments as it. When the relative humidity is 65% or above, you’ll likely see lots of slugs around, but only if your soil moisture levels are healthy!

In this way, you can use the presence or absence of slugs to get information about your soil quality. 

Moist soil = slugs, dry soil = no slugs! 

However, there are plenty of other (more reliable) ways to do this, so I wouldn’t recommend this as your only testing method!

Cons of Having Slugs in Your Garden

Okay, we’ve been nice to the garden slugs and covered the pros. Now, onto the bad bits. What kind of damage do slugs do?

• Slugs spread disease: This is no. 1 on the list of cons because it can cause the most damage. Not to our plants, but to us! Slugs can harbour rat lungworm (Angiostongylus cantonensis) and Angiostrongylus costaricensis, parasites that typically affect rats but occur in slugs if they have eaten infected rat faeces. While the disease won’t hurt your plants, if a slug gets on your lettuce leaves and you eat it (heaven forbid!), this can cause serious harm.
• They eat flower buds: Slugs love everything about flower buds – their softness, high moisture concentrations and their nutrient content. Due to this, you can expect to lose a flower bud or 10 if adult slugs grace your garden.  
• They strip young trees of their bark: Young tree bark is also a favourite among slugs as it’s a vital source of moisture and nutrients. Slugs can also create hiding places out of bark strips which can protect them against predators! 
• Slugs eat bulbs: Bulbs of staple British garden plants like tulips and daffodils store the nutrients these plants need to grow and flower, making them an ideal food source for slugs. Unfortunately, this can mean that when early spring comes around, the spring-flowering garden you thought you were going to enjoy could be non-existent!
• They can destroy young seedlings: Young seedlings are made from super soft organic tissue, making them far easier for slugs to chew than a lot of older, tougher plants. Like bulbs and flower buds, seedlings hold high nutritional value, so slugs love to munch away on them. Good for the slugs, bad for us gardeners!
• Slug slime looks awful: This con is more down to personal preference than anything else. But speak to any gardener, and they’ll likely tell you what an eyesore slug slime is! When you spend hours tending to your beautiful garden, only to see slug slime everywhere you look, you’ll likely have something to say about it!

As you can see, having slugs in your garden has far more cons than pros. Slug damage is a real problem for gardeners.

So, how can you manage slugs in your garden? 

6 Ways to Manage Slugs in Your Garden

Still can’t stand these natural predators after considering all factors? Let’s think about some of the best slug control methods!

1. Create a Slug Beer Trap 

Want an effective way to trap slugs in your garden so they can’t cause plant damage? Then try the slug beer trap method! This handy slug trap lures slugs in and then traps them inside so they can’t get at your plants.

Simply find a wide, shallow container and some cheap beer. If you want to go the extra mile, source a lid with holes and garden stakes. Here’s what you need to do:

1. Bury the container in the ground in a spot where slugs are particularly prevalent. Dig deep enough so the container’s rim is level with the soil surface.
2. Pour beer into your container up until the halfway point. 
3. Create a lid by poking holes through the lid of the plastic container or make a lid out of waterproof tape.
4. Strategically place garden stakes around the container to make the beer easy to access.

Now, simply monitor your beer trap and empty it when necessary! Slugs are typically more active early and late in the day, so check your trap after these times!

2. Deter Them With Grapefruit Halves

Citrus fruits like grapefruit are the perfect natural pest control method for those of you on a budget, as they cost next to nothing, and you may even have them lying around your kitchen! 

Slugs love citrus fruits – they’ll choose these over herbaceous plants any day! This makes them a great deterrent, keeping your other plants, as well as the slugs, happy! 

3. Try the Ol’ Soapy Water Trick

Soapy water can be used in many ways in your garden, including as an effective way eliminate slugs. Dish soap damages a slug’s protective mucus layer, causing dehydration which makes it difficult for them to produce slime and move around. 

Simply fill a container or bucket with soapy water to the ratio of 15 ml soap to 4.5 litres of water. Mix it together slowly so as not to create too many bubbles, then spray your plants with the soapy solution. Give your plants a good coating; otherwise, it’s unlikely to deter those pesky slugs!

If the solution above isn’t working, increase the amount of dish soap you’re putting in – that should do the trick!

4. Lay Down Coffee Grounds 

Coffee grounds are one of the best organic slug baits as they act in several ways.

They have a slightly acidic pH, which can cause slugs irritation if they crawl across the soil surface.

Coffee’s high nitrogen content also dries out the slugs, making it difficult for them to move.

Finally, slugs hate the texture of coffee grounds! Consider the coarse texture coffee grounds have, then think about the slimy surface of slugs – the two don’t go well together!

Unlike chemical, store-bought baits like metaldehyde baits, coffee grounds aren’t harmful to other species of wildlife, so they’re the perfect alternative.

Simply sprinkle used coffee grounds on vulnerable areas of your garden, like your veg patches and flower beds, then add more when it rains. 

READ NEXT: Composting With Coffee Grounds – Good For Plants or Just a Fad?

5. Shock Slugs With Copper Tape

Many gardeners will have heard of the copper tape slug deterrent method. Copper tape gives slugs a mild electric shock when they crawl across it, so it works as a natural aversion! 

To try this method, buy slug-repellent copper tape (not just any old copper tape!), then stick it down on a clean, dry surface. For example, the outer edge of a plant pot, the wooden edging of a raised bed, or the patio tiles on which your pots sit!

Top tip: You’ll find copper tape is most effective in places like raised beds, containers, and pots because it can completely cordon off these areas. It may be more difficult to cover the whole of your garden perimeter in copper tape!

6. Use a Yeast Mixture

Slugs are attracted to the carbon dioxide a yeast mixture gives off when it’s fermenting, so yeast is another great option to keep slugs off of your favourite plants.

So, how do you do it?

1. Mix 1 tablespoon of active dry yeast with 1 litre of warm water, then stir until the yeast has dissolved.
2. Leave your yeast mixture to sit for a few hours in a warm spot so that it can ferment.
3. Spray your yeast mixture onto the soil around your most vulnerable plants or spots that slugs seem particularly partial to. Ensure you make enough mixture for good coverage.
4. Reapply when it has rained or after you water your plants to keep the slugs away!

You could also use the yeast mixture to create a slug trap just like the beer trap mentioned earlier! Simply create the yeast mixture, then pour it into a container in the ground!

Final Word on Slugs In Your Garden

Are slugs good for your plants & garden? The general consensus would likely be: no. While having slugs in your garden does have some pros, the cons far outweigh these.

However, all isn’t lost! You can successfully keep slugs away from your plants by creating a beer trap, using organic baits like coffee grounds or grapefruit halves, shocking them with copper tape, or applying soapy water or an active yeast mixture to your beloved plants. 

If you enjoyed this article and want to learn more about common garden pests, you’ll love our article on 13 Common Garden Pests & How to Keep Them Out!