The A - Z Of Garden Slugs - Fascinating Facts And Top Tips

A LIST OF 26 FASCINATING FACTS ABOUT SLUGS
AND HOW TO PROTECT YOU PLANTS FROM SLUG DAMAGE

Slugs are one of the most common garden pests and when faced with a slug infestation plant protection will become serious business for the keen gardener. Finding the best way of combating slugs without the use of harsh chemicals can prove tricky, which is why we've put together this A to Z of garden slugs which describes many of the different approaches gardeners have taken to combat this hungry mollusk!

Arion Hortensis, also known as the common garden slug, is just one of several species of slugs which you might in your garden. This relatively small slug (about 3cm long) is the most likely one to find, but others include the great grey slug – which the RSPB website tells me can be up to 20cm in length and the large black slug also named ‘arion ater’. Whatever the species they can still cause mayhem in your garden. 

Beer traps are the traditional way of getting rid of slugs. To create a beer trap and protect specific plants within your garden you will need to have a watertight container which can be buried near to the plants you wish to protect (keeping the rim of the container 2-3cm above the ground to prevent slug-eating ground beetles from falling in). Then half fill the container with beer. The scent of the beer will attract slugs, which will fall in and get stuck, thus protecting your plants.

Creating a beer tray is much easier, neater and more efficient if you use a purpose-made beer trays, such as our Slug and Snail Traps. Their colour makes them unobtrusive in your garden, whilst their lid keeps their contents away from reach of other animals, whilst still attracting slugs to a happy end.

Copper Tape creates an effective barrier to slugs as copper reacts with slug slime, giving the slug a little electric shock each time they come into contact with the tape. Our self-adhesive tape can be easily attached to greenhouse staging, plant pots, raised beds, etc etc to create an effective ‘electric’ barrier to efficiently protect your plants. Its good to remember, to keep the copper tape working effectively it needs to be cleaned regularly – using a vinegar solution will prevent the copper from tarnishing.

Dead plants and animals are some of the favourite foods for slugs as they act as scavengers, helping to remove dead and decaying leaf debris on the ground as well as insects, small birds and animals which they come across on their travels. They will also do a good job of munching their way through your biodegradable rubbish, including paper, compost and bark. It’s just a shame that slugs also like tucking into new green growth, fresh vegetable and fruit just as much! 

Egg shells are a great home remedy for stopping slugs – although not guaranteed to work, slugs prefer not to travel over sharp surfaces, so a barrier of broken up egg shells should work to protect your plants. Using eggshells also has the added benefit of enriching your soil with calcium as the egg shells decompose. If you don’t tend to have egg shells available, then broken nut shells would work just as efficiently.

Fresh or powdered seaweed is both a great slug repellent and a great way to add nutrients to your soil. The reason it works well as a slug deterrent is because of its high salt content – and we all know slugs don’t like salt! Simply place the seaweed or sprinkle powdered seaweed around the plants to protect and its that easy to create instant slug protection.

Ground coffee beans (note – not instant coffee granules) sprinkled around your plants will help provide a protective barrier against slugs as they hate coffee (and the higher the caffeine content the better). And the good thing is if you don’t have ground coffee beans to hand, some well known coffee shops will give their customers free coffee ground from their machines. So this is a free and easy way to prevent slug damage.

How many slugs could be living in an average British garden? You will be surprised to know that there could be as many as 20,000 slugs and snails taking up residence in your garden – that’s about 200 slugs to metre squared! So it’s no wonder that you can go to bed and have all healthy plants and wake up I the morning and just find green stumps as slugs have had a midnight feast!  

Identifying the best place to eat can take time, but the garden slug makes this easier for themselves and their mates by leaving a map of their travels. Slugs can follow the trail of slime they left from the day before to reach the plants they liked best – these same slime trails will be used by other snails searching out food. In this way this icky garden pest will create an efficient slug network letting then efficiently reach their favourite foods.  

Jagged edges as a slug eats their way through your plants or crops are caused by their tiny, grater-like teeth that shred leaf tissue before it’s digested. Slugs are greedy eaters and can consume up to forty times their weight in just 24 hours!! So it’s not surprising that slugs can cause so much damage when they find their way into your garden or greenhouse.  

Did you know that slugs have approximately 27,000 teeth! These microscopic teeth form a flexible band known as the ‘radula’. It is the radula which scrapes up, or ‘rasps’ the slugs chosen food – this efficient eating machine uses it’s jaw to cut off larger pieces of plants to eat and then rasps its way through its meal with its 27,000 teeth.

Knowledge is power, the famous quote from Sir Francis Bacon, definitely applies when it comes to gardeners getting the upper hand when protecting their plants from slugs. For example, did you know that when you pick a slug off one of your plants and happily sling it into someone else’s garden, unless you are an Olympic thrower and can propel the slug a distance of over 20 metres, then that little slug will be bringing itself right back to your garden – albeit, somewhat slowly. The homing instinct of a slug has been researched and it has been demonstrated that they can make their way back to where they came from over short distances as they leave a unique scent trail which they can follow to find their way home, their home in this case being your garden.  

Laying hundreds of eggs in a lifetime, slugs will lay up to 30 eggs at a time. Slugs will lay their eggs in moist soil, under mulch or rocks or under piles of leaves. The eggs will remain dormant for just the right moment to hatch – the warmer the weather the faster the eggs will hatch. For example, eggs laid during the warmer months could take just 2 weeks to hatch, whereas eggs laid in the winter could take up to 5 months to hatch.

Manually remove slugs from your garden efficiently by creating an area to attract slugs where you can scoop them up and dispose of them. A small pile of old lettuce or cabbage leaves, dry cat food etc placed in a damp and shady of your garden will work at attracting slugs to one area of your garden. This method does take time and patience and the ability to scoop up these slimy little predators and dispose of them straight away. Not a good method if you are squeamish!

Natural predators of slugs include badgers, hedgehogs, newts, song thrushes and toads, so if you encourage these animals to visit your garden then they will help you out by keeping slugs in your garden under control.

Overnight citrus traps are a great way of using your kitchen waste to create an attractive haven for slugs that you can neatly dispose of in the morning. So if you’ve had grapefruit for your breakfast, turn the remaining rind into a neat trap – simply turn upside down, creating a grapefruit ‘igloo’ close to your plants and leaving sufficient space for the slugs to gain access. Leave overnight and slugs will be attracted by these citrusy, damp environments – in the morning simply scoop up the grapefruit halves including their new residents and dispose of it all together. It’s that simple!

Prickly barriers are a great way to deter slugs from reaching your plants. Barriers made from crushed egg shells, thorny cuttings, pine needles etc are both a great way of creating an eco-friendly barrier which these soft-bodied molluscs, slugs, will not want to pass.

Quite disgusting to most gardeners, you might be surprised to know that some people keep slugs as pets. Although an unusual pet, they are easy to care for, easy to feed and easy to keep safe and will live for up to five years.  

Rosemary in a plant which can be used to naturally deter slugs – other plants which slugs don’t like include anise, astrantia, fennel, rue and wormwood. So growing these plants in your garden is a good, eco friendly way to reduce the number of slugs taking up residence in your garden. This way of creating pest protection for one plant by planting another is known as 'companion planting'.

Slippery surfaces are difficult for slugs to scale, so to protect plants in pots you could spray the outside of the pots with WD40.

Trails of slime in your greenhouse, across your patio, up the sides of pots or furniture are one of the ways of identifying you have a slug infestation. Slugs move on an excreted mucus trail which has two primary functions – it protects their bodies from desiccation – and it also alerts other slugs to their presence (one way these slimy pests can find a mate).  

Upper tentacles and lower tentacles are important parts of a slug’s anatomy. The upper pair are for vision and smell, whilst the lower pair are smaller and are used for feeling and taste. These tentacles are retractable, and each tentacle can be moved independently of the others.  

The upper tentacles are called optical tentacles as they have light sensitive eyespots on the end – these appear as small black spots on the end of the tentacle. It should also be noted that slugs are able to  regrow their tentacles if severely damaged.

Vapor rub or petroleum jelly (such as Vaseline) can be used on the surface of pots or containers to protect the plants they contain. Simply create a ring of rub or jelly around the pot – this creates a slippery barrier which slugs will find difficult to cross.

Wool Pellets, by nature, are a good slug repellent. If you were to look at a wool pellet using a microscope you would see that the wool fibres forming the pellets are barbed. It is these barbs which the soft bellied slug doesn’t like. So, if you have specific plants in your garden you wish to protect, create a ring of wool pellets around the plants and this should deter slugs from reaching your them.  

X-raying a slug would show you that it has no internal skeleton. Rather, these invertebrates have soft bodies that they ‘drag’ around on a single, muscly foot. However, most species of slugs do have a small concealed fragment of shell in their body which is used as a place to store calcium salts, often in conjunction with the slugs digestive glands.  

Yearly British gardeners will use over 4,000,000,000 slug pellets in their war against this common garden pest. According to the Royal Horticultural Society, after research carried out in 2020, slugs and snails are the top of the pests chart with gardeners reporting damage to crops such as potatoes and beans.  

ZZzzzzzzzzzz although slugs do sleep, unlike ourselves who group our time into 24 hour cycles, slugs do not. Slugs will sleep on and off for several hours at a time but then might stay awake for 30 hours without a break. Slugs may also hibernate, depending on the weather conditions. They will stay active when temperatures remain above 5 degrees Celsius / 41 degrees Fahrenheit. This means that when we have warm winters slugs may not hibernate, giving them longer to eat and breed. So the possibility of super-sized, sleepless slugs could be a real problem if we have warmer and warmer winters.