Wage war on slugs

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They are every gardener's nemesis, capable of destroying a single plant in one sitting and able to devastate whole rows of seedlings. Anyone who has carefully nurtured trays of bedding plants in the greenhouse only to bed them out and have them disappear in the night will have an abiding hatred of slugs.

They like tender, soft, green growth and their rasping mouthparts can take care of most delicate plants and they seem inordinately attracted to hostas. You couldn't blame any gardener for wanting to commit mass murder on these slimy little horrors.

Know your enemy

The best way to arm yourself against any pest is to know a little about what they are and the way they think.

Slugs are not insects. They belong to the family of molluscs which puts them in the same category as mussels, cockles, snails and even octopus and squid. Unlike many of their relatives, slugs are shell-less. Without a portable home to shelter in, they have to find other means of shelter and protection so, the first tactic in the battle against slugs is to deprive them as much as possible of a place to hide.

Slugs have moist bodies which dry out very quickly so they must not allow themselves to be exposed to sunlight. This is why they produce slime - to keep their bodies moist. Because of this, they mostly come out on wet days or at night. However, they don't actually like rain to fall directly on them so they will tend to wait until just after rainfall to emerge. So, if you plan to go slug hunting, choose a nice, moist day, immediately after the rain or do it at night.

They are sensitive creatures too. They prefer to travel over soft ground where their bodies won't be damaged and we can use this to our advantage by surrounding favoured plants with eggshells or gravel in an attempt to put them off.

Chemical warfare

You can, of course buy a chemical pesticide which kills slugs. Technically, these are known as molluscicides and are most commonly encountered as slug pellets. People who use slug pellets tend to excuse themselves by claiming they are the only thing that works but, if you want to kill slugs, toads, birds, cats, dogs and just about any other living thing in your garden, go right ahead and use them.

Slug pellets have been implicated in the deaths of many of our native birds and even in the deaths of domestic cats and dogs. Slug manufacturers understandably hold a different view and they claim that all the condemnation of slug pellets is based on misinformation by gardening journalists and the like. You can read further information for and against slug pellets by clicking on the links in our 'related content' section.

Biological warfare

You can buy biological pesticides for killing slugs and these usually come on the form of tiny nematode worms. Products like Nemaslug have these worms suspended in a liquid which you simply water into the soil. The worms are parasites of slugs and burrow into them, killing them in around three days. This seems quite a cruel death for the poor slugs but it is supposed to be kinder to the environment than chemical means so, if nothing but death to all slugs is your aim, biological control is the way to go.

Trap and kill

The old method of placing beer traps around your garden is still very effective. Simply place a container of beer into the soil up to is rim. The slugs are attracted to the beer and fall into the trap and drown. You will need to replace your beer traps around every two weeks or after it has rained. You can also trap slugs by providing the ideal shelter. An upturned pot or half of the skin of a melon or grapefruit, will attract slugs during the day when they will attempt to get out of the heat of the sun. You can pick them off easily and kill them by dropping them into a salt water solution or some rubbing alcohol.

Put them on work detail

Believe it or not, slugs actually prefer decomposing plant material and only attack your fresh growth when this is not available. You can use this preference to your advantage by putting slugs to work in the one place in the garden where they actually do some good. Go out at night with a torch and pick off as many as you can and simply throw them on your compost heap. Once there, the slugs find the perfect home in the top layers of the heap. With more than enough of their favourite food to eat and a nice damp environment in which to hide during the day, your slugs will happily live out their entire lives in the compost heap without leaving it and they will be doing you a favour by helping to break down your compost. Because they remain at the top of the heap, you are unlikely to transfer them back to the rest of your garden because you always take compost for spreading from the bottom. This seems the perfect solution to controlling slugs especially since some of the slugs in your heap will also be available as food for gardener's friends like toads and slow worms.

Employ an army

Much as we gardeners might hate slugs, we shouldn't wish for their total destruction. because they are food for so many more lovable creatures. Slugs are hemaphrodite, which means they can be either male or female and this allows them to breed very efficiently. Nature has allowed this because they are food for so many more lovable creatures. Toads, hedgehogs, centipedes, frogs, slow-worms, rove beetles and many species of birds regularly eat slugs. If you encourage these creatures into your garden, they will reward you by eating enough slugs to keep the population under control. A little saucer of milk and some dog food will bring hedgehogs to your door every night and you can create shelters for slow-worms, rove beetles and centipedes by providing a warm, dark place for them to hide in during the day. Frogs and toads will happily move into a small pond.

Image by Chrissies

Fortify your borders

Anyone who has tried to grow hostas will know the frustration brought about by a slug attack. Slugs are attracted to hostas because hostas like the same damp conditions that slugs prefer. You can grow hostas and many other plants by mulching around them with sharp grit or gravel. Slugs hate to travel over sharp things because it damages their skin so they won't risk attacking your favourite plants.

You can put up barriers like this around any plants you feel might be at risk and it is true that gravel gardens rarely suffer from slug damage.

Don't encourage them in the first place

The final method of controlling slugs is simple. Just don't plant the kind of plants they like. Slugs have a preference for certain herbaceous plants over others so, by process of elimination, you can eventually create a garden where slugs is rarely a problem. Day lilies, hardy geraniums and achilleas, for example rarely constitute a decent meal for any self-respecting slug whereas hostas, delphiniums and hollyhocks appear to be favourites. Experiment with your plants and, if they can't stand up to the slugs, get rid of them in favour of something else.

Learn to share

Whatever method of slug control you use, it is important to remember that there are worse enemies to have than the slug. After all, it's not as if they are a foreign interloper bent on destruction. They are, at least, a native pest and as such, nature has given us the predators to keep their populations under control. A few eaten plants is a small price to pay for a garden that is alive with birds and other creatures. Give me that any day over a sterile environment where nothing else lives but rows and rows of lettuce.

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