Slugs and snails
(Numerous species) Slugs and snails are probably the most recognised and most destructive pests of garden plants. They will eat and damage just about any plant they come across.
- Slugs: slimy, soft-bodied animals on the ground, walls and fences and on leaves, stems and flowers
- Snails: soft-bodied animals that retract within their shells when disturbed on the ground, walls and fences and on leaves, stems and flowers
- Slime trails, a silvery deposit, wherever they have travelled
- Irregular holes and damage on any plant parts
- Young plants and seedlings completely killed, cut off at ground level
- Damage and tunnelled holes in underground bulbs and tubers
What are slugs & snails?
Slugs and snails are gastropods (molluscs) with soft bodies. In Britain, there are more than 40 species of slugs and more than 100 species of snails. Slugs come in a range of sizes from 2.5-20cm (1-8in) long, and colours including grey, black and orange. Snails also come in a wide range of sizes and have variously shaped and coloured shells. The shell helps protect them from drying out during hot and dry weather.
In winter, snails tend to hibernate, but can be active during mild spells of weather, whereas slugs tend to be active all year round.
They mainly breed in spring and autumn, producing clusters of spherical white or yellowish-white eggs.
Not all slugs and snails eat live plants, some feed on dead or decomposing plant and animal matter.
What do they affect?
- Mainly soft-leaved plants – but just about any plant is susceptible
- Young plants and seedlings
- Herbaceous perennials
- Bulbs and tubers
What do they do?
Slugs and snails are undoubtedly the most common and the number one garden plant pest problem. They attack a wide range of young and tender garden plants, especially annuals, perennials – particularly hostas – and vegetables.
Slugs and snails eat irregularly shaped holes in leaves, stems, buds and flowers, as well as bulbs, corms and tubers, using their rasping tongues. Voracious feeding activity can reduce young plants to a stump! Some slugs, especially keel slugs, spend most or all their life underground and are a real problem on potatoes and other underground storage organs, like bulbs and tubers.
Most slugs and snails tend to feed at night, although not exclusively, and will feed during the day during wet weather. The tell-tale slime trails may be present, indicating their activity – but not always. Slug and snail damage is most severe during warm, humid weather, especially in spring and autumn. When hot, dry weather occurs, they tend to find somewhere cool and moist to hide away.
How to control slugs & snails
As both slugs and snails are so common in every garden (up to thousands even in a relatively small garden) some damage is to be expected – and even tolerated.
It is important to check plants regularly, and dealing with any slugs and snails you see, or signs of their activity and damage – as soon as you see them. Those plants known to be susceptible, new young shoots in spring and recently planted young plants and seedlings – which are particular favourites and can be completely killed – should be protected to prevent slugs and snails getting to them in the first place.
Slugs and snails have a lot of natural predators – including birds (especially thrushes for snails), frogs, ground beetles, hedgehogs and toads. So always do whatever you can to make your garden as friendly for these animals as possible and encourage them to deal with slugs and snails for you.
Go out in the evening on slug and snail patrols and hand pick any you see. Take them far away from your home (snails have a homing instinct, and will travel back to your garden otherwise) to get rid of them or kill them in hot water.
There is a biological control based on nematodes for slugs, but this doesn’t work on snails, called Nemaslug. This is watered onto the compost or soil from spring onwards.
You can place traps, such as scooped-out half oranges, grapefruits or melons, or jam jars part-filled with beer sunk into the soil, near vulnerable plants. Check them and empty them daily. Beer traps may also trap other animals, including ground beetles that eat slugs.
Place suitable barriers around susceptible plants. These include anything sharp and gritty including sharp sand, egg shells and cinders. Moisture-absorbent materials are available, which also prevent slug invasion, including Doff Slugs Be Gone and Vitax Slug Gone. Many barriers placed around plants on the soil won’t stop those slugs that live in the soil.
You can also use copper tape, especially around pots or raised beds, or use mats of Agralan Slug and Weed Mat or Slug and Snail Shocka, which is impregnated with copper. Copper produces a mild electric shock that deters them.
Thinly scatter slug pellets on the soil around vulnerable plants; don’t pile them up under bricks or half grapefruit skins, as this isn’t how they should be used.
If you’re worried about using standard slug pellets, there are many alternatives containing ferric phosphate. This is approved for organic gardening.
Put your slug and snail barriers and other control methods in place early in the year, as and when new growth starts to appear above ground level and whenever planting out young plants and seedlings. Prevention is definitely better than cure!
Rake up and dispose of fallen leaves and any other plant debris, as these make excellent hiding places and breeding grounds for slugs and snails. Generally tidy up the garden to remove their cool, moist hiding places.
- Slug & snail barriers
- Slug & snail deterrents
- Slug & snail pellets