Dealing with Slugs and Snails
Deterring Slugs and Snails
You are unlikely to completely rid your garden of these pests, but there are some precautions you can take to minimise their colonisation.
Hiding Places
Taking account of their favourite hiding places, it helps if you can deny them such opportunities. To do this completely would mean having no garden at all, which would be self-defeating. However, you can at least remove unnecessary rubbish from your garden and keep it reasonably tidy.
Slugs lay their eggs in soil where many survive the most severe winters. Where you are able, it is worth digging over or hoeing bare soil before the winter sets in. This gives predators an opportunity to find and eat the eggs.
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Barriers
In theory at least, slugs and snails don't like crawling over anything that is dry and scratchy. Consequently you can give some protection for vulnerable plants by providing barriers around them.
Materials that have been suggested for this purpose include:
- Eggshells that are crushed fine
- Ash from burned wood again crushed fine
- Coarse sand or gravel the sharper the better
Whilst such barriers may have an effect, the downside is that they are easily breached by rain or wind. They can also be disturbed by other garden visitors, including worms that take the material down into the soil. Once the first gap appears they no longer provide any effective protection.
Consequently, to maintain their effectiveness, it is necessary to inspect them regularly and repair any gaps as soon as they appear.
Another form of barrier is copper in various forms. The theory is that when slugs and snails attempt to cross copper, they generate a mild electric shock, which deters them.
Designs of copper rings are available commercially but are significantly more expensive than some of the other deterrents. Consequently, you may only be able to use this method for particularly important plants.
Of course, all your efforts are wasted if you then import more slugs from elsewhere. For this reason it is always worth inspecting new plants for signs of slugs, snails or their eggs.
Getting rid of slugs and snails
Many methods have been advocated for getting rid of slugs and snails. They roughly fall into the following categories.
- Predators
- Mechanical
- Chemical
- Organic
Not all of these methods are appropriate for all situations and therefore gardeners need to consider those that are suitable for their gardens and their own personal preferences. If possible it is good if you can employ a number of methods in combination.
Predators
There are many common visitors to your garden that enjoy feasting on slugs and snails including for example:
Birds
There's a variety of things you can do to entice birds to regularly visit or even take up residence in your garden. A bird table with scraps and various bird feeders will attract birds in the first place. Good nesting sites also help, such as dense hedges or purpose built nesting boxes.
Hedgehogs
Hedgehogs need places to hibernate over winter so you need to provide suitable accommodation such as log piles or mounds of dried leaves. If you want to feed hedgehogs, then dog or cat food is the best option, but ensure it is being taken by preferred visitors since you may inadvertently be attracting rodents. There is a false idea that hedgehogs like bread and milk but this is a mistake and can actually do more harm than good.
Frogs, Toads and Newts
These creatures all need water, though they spend most of their time on land. Consequently, a small pond is ideal if it is easy to get in and out. Generally being nocturnal creatures, you also need to provide shelter for them during the day by way of dense plant cover or piles of rocks and stones.
Shrews
Shrews live on a diet of worms and insects as well as slugs and snails. They generally like to burrow to make a home so you need to take this into account especially if you have a small garden and are not able to set aside an area that is uncultivated.
There are other natural wild predators but these are probably the most common and effective.
In addition to wild creatures, many people claim that ducks, geese or chickens are an effective means of controlling slugs. Unfortunately they can make their own mess of the garden so they may not be your first choice unless you have other reasons for keeping them. The major drawback with such livestock is that you need effective defences against foxes.
Mechanical
By this we mean physically hunting and removing individual slugs and snails. For example, it is worth watching for adults or eggs whenever you are digging over the soil. Simply leaving them exposed may be sufficient to attract birds to do the work for you.
It is surprising how effective you can be in controlling slugs and snails by hand picking them and then disposing of them. It helps if you can entice them to gather together so you don't need to do so much hunting.
You can encourage slugs and snails to congregate together by placing "traps" around the garden in the form of flat pieces of wood, slate, stone or similar materials that provide a "safe" place for the creatures to hide during the day. They don't need to be large perhaps six inches to a foot across should be sufficient. Upturned pots are also effective for this purpose. Use small stones to prop them up and so provide a means of entry. Lift the traps each morning and dispose of anything that is hiding there.
Traps can also be created from small pots (e.g. yogurt pots) that are sunk into the ground so that their rim is level with or slightly higher than the soil. You can buy containers specially made for this purpose. Fill with beer, which attracts the slugs and drowns them. It doesn't matter if the beer is out of date since it is just as effective for this purpose. If you don't have beer then any sweet sugary drink will do.
When conditions are right, slugs and snails are most active around two to three hours after sunset and therefore, this can be a good time to locate and destroy them. Bear in mind, however, that they dislike rain and strong wind so will not emerge until conditions improve.
How you choose to dispose of dead slugs and snails depends on your personal preferences but it is worth remembering that they are a favourite delicacy of many birds.
Poisoning
Slug pellets is perhaps the most popular method for controlling slugs and snails, and it is certainly effective, though it has a number of serious drawbacks. The pellets can contain a variety of chemicals, some of which are more water resistant than others. Those containing metaldehyde are easily available, not very expensive and appear to be most effective.
You need to take care in using any kind of poison, particularly since they are not particularly selective and can affect other life forms, causing severe sickness or even death. It is vital, therefore, to read and follow the instructions carefully. You may even harm other life forms that eat the dead slugs and snails because of the residual poison in their bodies.
If you have pets or young children that like to test everything by putting it in their mouths, then this method is definitely not recommended.
One option to reduce the effect on other creatures is to use the pellets in conjunction with "traps" as mentioned above so that they will be found by slugs and snails that are seeking shelter after they return from feeding. However, this precaution may not be sufficient to protect curious children from being poisoned.
Organic or Biological
Many gardeners prefer to use nature's own methods to keep pests under control and there are biological methods that are particularly helpful for destroying small slugs that live under the soil where they may not be obvious to most other predators.
There are various small worm-like creatures known as nematodes that are useful against garden pests. In particular, Phasmarhabditis Hermaphrodita attack slugs and snails and kill them by laying their eggs inside them. These need to be applied every few weeks by watering them into the soil or by applying them in a powder form.
Although this can be a relatively expensive option, the great benefit of this form of control is that you are not harming any other creatures or damaging the environment.
Disposing of Dead Slugs and Snails
Whether you drown them, poison them or kill them by some other means, many people are confused about how best to dispose of the dead creatures. This is a particular concern if you use slug pellets in case eating the poisoned molluscs harms other wild creatures.
In practice, if you leave dead slugs and snails laying around in the garden for a few days the chances are that they will still be there when you go to look again. In other words, for whatever reason, those creatures that like to feast on slugs and snails seem to prefer them alive rather than dead. If they are eaten, they are as likely to be consumed by others of their own kind than by birds or animals. Consequently, the fear of poisoning other wildlife, whilst it cannot be ruled out completely, appears to be less likely than first thought.
You can actually dispose of dead slugs and snails in any way that is convenient. That includes throwing them into the compost, into the dustbin, burying them or whatever other ideas you may have that you personally feel comfortable with.