How to get rid of slugs and snails

What can I use to deter and get rid of slugs?

Gardeners traditionally use things such as crushed eggshells, sharp sand and soot to repel slugs, but these have limited success. There are also a wide range of barrier methods available, from granules that are supposed to dry them up, to copper rings. In the Which? Gardening magazine trials we found that only a few of them work well. 

When Which? Gardening magazine tried chemical controls we had good results from slug pellets containing ferric phosphate, such as Growing Success Advanced Slug Killer. For plants in the ground, we found the biological control Nemaslug is effective against slugs but not snails.

Discover the best organic controls for slugs and snails

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What chemical controls can I use against slugs and snails?

There is one chemical option: pellets containing ferric phosphate. Ferric phosphate-based pellets stop slugs and snails feeding. They are currently approved for use by organic gardeners.

Do slug pellets pose a risk to wildlife and pets?

Metaldehyde pellets were harmful to wildlife and the environment and were banned from use in April 22.

Ferric-phosphate pellets are not thought to be damaging to mammals and birds. However, some research suggests that ferric phosphate pellets may not be as environmentally friendly as first thought. Some ferric phosphate pellets also contain a 'chelating agent' called EDTA, to make the iron more soluble. This may increase the amount of iron in groundwater, which can be toxic to earthworms in high doses.

If you use ferric phosphate pellets, concentrate your efforts on vulnerable plants; don’t attempt to eliminate slugs from the whole garden. Scatter the pellets thinly, as directed on the packet, as doses have been calculated to offer the best protection. Don't leave them in heaps. Regularly collect up the poisoned slugs and snails and consign them to the dustbin. Always store pellets in their original container, and safely out of reach of children and pets.

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Are there any biological slug controls for slugs?

Yes, you can buy biological controls that contain nematodes. There are millions of naturally occurring nematodes in each packet and they penetrate the slug’s mantle, carrying a bacterium that infects and kills the slug. They're best used in spring and autumn when the soil is warm and moist. 

They're watered into the soil, so are only effective against slugs. 

Suppliers of biological controls for slugs

• Green Gardener greengardener.co.uk
• Ladybird Plant Care ladybirdplantcare.co.uk
• The Organic Gardening Catalogue organiccatalogue.com
• Nematodes Direct nematodesdirect.co.uk

Can slugs and snails be discouraged?

Slugs and snails often target young plants or certain herbaceous plants as they start to put on new growth in the spring. Concentrate your deterrents around these plants, and remember that slugs and snails can be a problem from Valentine's day onwards. 

Carry out regular 'slug hunts' to find the pests. They are particularly active from dusk onwards, so take a torch and check around any dark, damp spots such as pots and under the leaves of ground-cover plants. 

Keep weeds down and clear away dead plants and rubbish. Often the number of slugs and snails varies around the garden; try growing vulnerable plants in areas where you see none. Avoid mulching vulnerable plants such as lettuce and potatoes.

For plants in pots, you can apply a slippery substance, such as WD40 or Vaseline to deter the slugs from climbing the sides of the container. 

A garlic spray can also offer some protection. Boil two full bulbs of garlic in 2L of water, then squash out as much juice as possible. Put the liquid into a spray bottle and mist your plants weekly. 

Growing plants that slugs and snails are particularly fond of is also effective. In Which? Gardening trials we found that marigolds were more likely to be eaten than hostas. Grow a few from seed and let the slugs and snails eat them rather than your prized plants. 

Try the five easiest veg to grow

Slug-resistant plants

You can minimise the damage caused by slugs and snails by choosing plants that they won't eat or rarely touch. The following Best Buys will all resist attack.

Anemone hupehensis var. japonica 'Pamina'

Height x spread: 80 x 100cm

Where to buy: Crocus

Japanese anemones start flowering in late summer and like reliably moist soil. This could be the ideal situation for slugs although, luckily, the plants have coarse, stiff and hairy leaves that don’t seem at all attractive to molluscs. Many varieties are enthusiastic spreaders, but charming, double-flowered ‘Pamina’ is compact and has much less of a tendency to roam.

Peak flowering: Aug-Oct

Maidenhair fern (Adiantum venustum)

Height x spread: 20 x 40cm

Where to buy: Beth Chatto

Elegant ferns add style to shady parts of the garden. The plants might suffer some damage when they’re very young and just unfurling, but once their stiff, tough fronds are past this stage, they’re rarely touched by slugs and snails. Adiantum venustum is just one splendid example of fern, forming a pretty mound of delicate and distinctive fronds that give it the common name of maidenhair fern. Plants were evergreen during our trial, but they may be semi-evergreen in colder areas.

Agapanthus 'Midnight Blue'

Height x spread: 80 x 70cm

Where to buy: Ballyrobert Gardens

Whether strappy or grass-like, agapanthus leaves aren’t favoured by slugs or snails. Any initial damage in spring is usually minimal and once they’re growing well, they’re rarely touched. Blue is the classic colour and ‘Midnight Blue’ – a deciduous variety – is a fantastic example, with sturdy stems holding long-lasting, attractive, deep-blue flowers.

Peak flowering: Jul-Aug

Bergenia 'Admiral'

Height x spread: 45 x 60cm

Where to buy: Beth Chatto

It’s not surprising that the leathery leaves of bergenia are much less attractive to slugs and snails than other more tender foliage – even if the molluscs tend to hide among the plants. B. ‘Admiral’ has typically tough but attractively shaped leaves, which turn red in winter. Their tall flower stems also show off the spring flowers to great effect.

Peak flowering: Apr-May

Dianthus 'Devon Wizard'

Height x spread: 40 x 45cm

Where to buy: Thompson & Morgan

The distinctive blue-grey stems and leaves of pinks are rarely eaten by slugs or snails. They’re also known to be ignored by deer, possibly because they can be a skin allergen to animals and people. ‘Devon Wizard’ is a great choice. It grows reliably well, has a lovely combination of flower and leaf colour, and a gorgeous scent.

Peak flowering: May-Jul

Digitalis purpurea 'Camelot Rose'

Height x spread: 130 x 50cm

Where to buy: Dobies

With leaves that are both toxic and hairy, foxgloves aren’t a favourite of molluscs. Easy to grow from seed, many are biennial so only flower for one year, although they tend to self-seed, so they don’t disappear completely. D. ‘Camelot Rose’ has very large and striking flowers that create an impressive display and they’re highly attractive to bees.

Peak flowering: Jun-Jul

Fuchsia magellanica 'Arauco'

Height x spread: 80 x 100cm

Where to buy: Dobies

A gardener’s favourite, fuchsias are happily untroubled by slugs or snails, which may be due to their bitter-tasting sap. Hardy fuchsias are the easiest to grow and they don’t come much better than F. magellanica ‘Arauco’. It’s a large but neat, bushy fuchsia with dark foliage and a mass of exquisite flowers that dangle from its stems.

Peak flowering: Jul-Sept

Geranium 'Blue Cloud'

Height x spread: 100 x 120cm

Where to buy: Claire Austin

Hardy geranium foliage can vary a lot between different species although, being hairy, none of them seem to be eaten by slugs or snails. ‘Blue Cloud’ features all the best attributes of these popular perennials, with its strong, healthy growth pretty much untroubled by any pest or disease. The profusion of pretty flowers lasts for months and attracts pollinators.

Peak flowering: May-Aug

Helleborus 'Anna's Red'

Height x spread: 40 x 40cm

Where to buy: Crocus

Hellebore leaves are stiff and leathery, and can irritate skin, so they don’t attract slugs or snails. They also flower in winter when molluscs are rarely active. ‘Anna’s Red’ is a real beauty, with marbled leaves, tall red flower stems and deep red blooms that stay colourful for months.

Peak flowering: Jan-Apr

Sedum 'Xenox'

Height x spread: 60 x 90cm

Where to buy: Farmer Gracy

The fleshy, succulent leaves of sedums can attract slugs when they first emerge in spring, but the plants grow strongly and are rarely attacked later on. The dark purple leaves of ‘Xenox’ are very attractive and add to the impact of the many small red flower heads that open above them. This variety flowers well over several months and forms a neat mound.

Peak flowering: Aug-Sep

Lavandula angustifolia 'Loddon Blue'

Height x spread: 45 x 60cm

Where to buy: Ballyrobert Gardens

Lavender is a small shrub rather than a perennial, but it’s so often grown with perennials that we’ve included it here. The foliage is aromatic and downy, and unattractive to slugs or snails. ‘Loddon Blue’ is a fantastic English lavender, which grows into a compact ball of scented foliage with large flowers held on upright stems.

Peak flowering: Jul-Aug

Peony 'Bowl of Beauty'

Height x spread: 85 x 60cm

Where to buy: Crocus

Mature peonies have quite tough leaves and stems that can be a skin irritant to animals, which might explain why slugs and snails leave them alone. ‘Bowl of Beauty’ is a deservedly well-known variety. It has rhubarb-pink spring growth and then a huge flush of large, showy flowers that last for three or four weeks.

Peak flowering: Jun

Penstemon 'Pensham Just Jayne'

Height x spread: 75 x 50cm

Where to buy: Sarah Raven

If penstemon are troubled by slugs, it’s usually only the new spring growth that will be attacked, with damage reducing or stopping once the plants are growing strongly. ‘Just Jayne’, one of the famous Pensham cultivars, is a stunning plant that produces masses of striking blooms on dark stems from midsummer to autumn. It’s neatly shaped and easy to grow.

Peak flowering: Jul-Oct

Salvia microphylla 'Cerro Potosi'

Height x spread: 115 x 120cm

Where to buy: Sarah Raven

The aromatic, hairy leaves of Mexican shrubby salvias aren’t often on the menu for slugs and snails. They’re less hardy than some of the European species, although ‘Cerro Potosi’ is hardier than most if it’s in well-drained soil. It’s a stunning plant that bears large, vibrantly coloured flowers. It also blooms freely for many months.

Peak flowering: Jun-Oct

Are slugs beneficial?

Most slugs live underground, and although some will eat roots and leaves, many others feed on plant debris and so contribute to keeping soil healthy.

What conditions encourage slugs and snails?

Slugs and snails are molluscs and need a moist environment to survive. Slugs thrive in damp soil or plant debris, retreating deep into the soil when the weather is dry. Snails maintain their moisture level by going into their shells. Both are active mainly at night, especially in spring and autumn when the weather is warm and wet. It's a good idea to go out to look for them when conditions suit them.