Key takeaways
- Nematodes watered into moist soil tackle slugs underground for about six weeks
- A torch-lit slug hunt on a damp evening is quick, free and works straight away
- Ferric phosphate pellets are the ones on sale now, so scatter them thinly
- Copper tape, eggshells, grit and wool pellets make little difference
- Grow slug-proof plants like ferns, hardy geraniums and lavender
- Never use salt, and avoid home-made sprays and WD-40
Mixing a few methods together beats relying on any one barrier.
The best way to get rid of slugs naturally is to use a few methods together. Water nematodes into the soil, go slug hunting with a torch on damp evenings, welcome slug-eating wildlife and grow plants slugs don’t fancy. Slugs love the UK’s mild, damp weather, so expect to keep at it from spring to autumn.
Getting to know UK slugs
Most garden damage comes from just a few kinds of slug. A couple of others are actually on your side.
The main culprits
- Grey field slug. Small and grey-brown. Found in almost every garden, and eats leaves, seedlings and roots.
- Garden slug. Dark with an orange underside. Lives mostly underground, eating roots and potatoes. You rarely see it, but the damage shows.
- Large black slug. Big and eye-catching, but mostly eats rotting plants rather than your crops.
- Leopard slug. Spotty and large. It eats rotting matter and even other slugs, so leave it be.
When slugs are active
Slugs like it mild and damp. They’re busiest in spring and autumn, come out at dusk and hide in damp, dark places by morning. They slow right down in cold weather and dry spells, but never quite stop.
| Season | Slug activity | Why |
|---|---|---|
| March-April | Rising | Soil warms and fresh spring growth appears |
| May-June | High | Warm, damp evenings and lots of young plants |
| July-August | Up and down | Quiet in dry spells, busy after rain |
| September-October | High | Damp autumn weather and new eggs laid |
| November-February | Low | Cold slows them down |
Ragged holes and silvery slime trails on lettuce: a slug has been dining overnight.
Nature’s slug control
Nematodes (Nemaslug)
Nematodes are the top natural option. They’re tiny worms, too small to see, that you water into the soil. They find slugs underground and kill them within about a week. Brands include Nemaslug and SlugClear nematodes.
How to apply:
- Mix the powder with water in a watering can.
- Water onto moist soil once it’s above 5C.
- Water the area well afterwards.
- Keep the soil moist for the next two weeks.
One dose protects for about six weeks. Apply in March or April, then again in August or September. Because nematodes work underground, they reach slugs that traps and torches never see.
Nematodes are alive, so keep the pack in the fridge (not the freezer) and use it before the date on the pack. Use the mix straight away once it’s made up.
Tip: Apply in the evening, onto damp soil. Sunlight kills nematodes. For container vegetable gardens, water the mix into each pot.
Wildlife helpers
Plenty of garden creatures eat slugs, and they work for free:
- Frogs and toads. A small pond with a shallow edge brings them in.
- Hedgehogs. Leave small gaps under fences and keep a log pile or leaf heap.
- Ground beetles. They hide under logs and stones and hunt slugs at night.
- Song thrushes. They pick off snails and slugs on lawns and open ground.
Keep pellets away from ponds and hedgehog routes, and leave a few leafy, log-piled corners.
Ferric phosphate pellets
Metaldehyde pellets are now banned, so ferric phosphate pellets are the ones you’ll find on sale. Use them sparingly. Scatter a few thinly around plants at risk, well spaced rather than in a ring, and follow the dose on the pack. Save them for seedlings and favourite plants in wet spells.
A hedgehog out foraging at dusk. A log pile and a gap under the fence help them visit.
Barriers: do they help?
Mostly, not much. An RHS trial found that copper tape, eggshells, wool pellets and grit made no real difference to slug damage. Treat them as small extras at most.
Copper
Copper tape and mesh are widely sold, but they don’t reliably keep slugs out of pots, raised beds or cold frames. Slugs already in the compost, or climbing in via an overhanging leaf, get past it anyway.
What works better: raise pots on feet or a bench, water in nematodes, check plants by torchlight on damp evenings, and scatter a few ferric phosphate pellets if damage is bad.
Wool pellets
Wool pellets swell when wet into a scratchy mat. Slugs don’t seem to mind much, so don’t count on them. They do add a bit of organic matter to the soil.
Grit and sharp materials
Grit, crushed shells and diatomaceous earth sound like they should work, but slugs cross them happily in damp weather. They also sink into the soil quickly. Use grit for drainage instead.
Cloches and netting
Covers protect seedlings while they’re small and tasty. A clear plastic bottle with the bottom cut off makes a handy mini cloche. Take it off once the plant is bigger and tougher.
A cut-off bottle makes a free mini cloche while seedlings are small and tasty. Take it off once the plant has toughened up.
Traps and evening slug hunts
Beer traps
Sink a yoghurt pot or jam jar so the rim is level with the soil. Fill it with cheap beer. Slugs follow the smell, fall in and drown.
Each trap only covers a small patch, so you need a few along a border. Empty and refill every two or three days. They catch plenty but won’t clear a whole garden on their own.
Grapefruit and melon traps
Put upturned grapefruit halves or melon skins on the soil at dusk. Slugs shelter underneath overnight. Collect them in the morning. Cheap, easy and handy alongside other methods.
Evening hand-picking
Hand-picking gives the quickest results. Head out after dark with a torch and a bucket and pick slugs off plants and soil. A short session clears plenty. Focus on hostas, lettuce and young seedlings.
Mild, damp evenings after rain are best, from dusk until late evening. Two or three hunts a week in spring and autumn keep the worst damage down.
Please don’t use salt. It’s a slow, cruel death for slugs, and it harms your soil and earthworms too.
A torch and a bucket on a damp evening: simple, free and surprisingly satisfying.
Garden habits that keep slugs down
How you look after your garden makes a big difference.
Fewer hiding places
Slugs spend the day under stones, pots, thick ground cover and piles of rubbish. Tidy borders, raise pots on feet and clear dead leaves. Keeping on top of lawn weeds removes more damp cover too.
That doesn’t mean a bare garden. Log piles, compost heaps and leaf litter shelter slug-eating wildlife as well, so keep a balance.
Better drainage
Slugs love soggy soil. Dig in organic matter or use raised beds to help water drain away. Plants in well-drained soil grow stronger and cope with a nibble better.
Open spaces
Slugs don’t like crossing dry, open ground. A gravel path or strip of bare soil between a border and the lawn helps in dry weather. Keep slug favourites away from thick hedges and walls.
Timing
Don’t plant out tiny seedlings. Grow them on in pots until they have four to six true leaves, then plant out. Bigger plants survive a nibble, while tiny ones vanish overnight. If you’re starting a vegetable garden, plan for slugs from day one.
Plants slugs leave alone
The easiest slug control of all is growing plants slugs don’t like. Tough, hairy or strongly scented leaves put them off.
Perennials slugs avoid
Ferns, hardy geraniums, astilbes, foxgloves, lavender, rosemary and euphorbia are all good choices for a slug-prone garden.
Vegetables that resist slugs
- Garlic and onions. The strong smell puts slugs off.
- Tomatoes. Slugs may nibble low fruit but leave the plant alone.
- Chard and perpetual spinach. Tough, waxy leaves.
- Broad beans. Rarely bothered once they’re growing well.
- Herbs. Rosemary, thyme, sage and oregano.
Plants slugs love (protect these)
- Hostas, especially thin-leaved ones
- Lettuce and salad leaves
- Dahlias, when the shoots come up in spring
- Delphiniums (a cottage garden favourite that needs looking after)
- Marigolds
- Strawberries (the fruit, not the leaves)
- Young seedlings of almost anything
| Plant | Slug resistance | Notes |
|---|---|---|
| Ferns | Excellent | Rarely touched |
| Hardy geraniums | Excellent | Scented leaves |
| Hostas (thick-leaved) | Fair | Better than thin-leaved types |
| Hostas (thin-leaved) | Poor | Need protecting |
| Lettuce | Very poor | Always protect |
| Lavender | Excellent | Too strongly scented for slugs |
| Strawberries | Poor (fruit) | Tuck straw under, hand-pick at dusk |
| Dahlias | Poor (spring shoots) | Protect new growth |
Month-by-month slug calendar
| Month | What to do |
|---|---|
| January | Order nematodes for spring. Plan some slug-proof planting. |
| February | Look for slug eggs (small white clusters in the soil) and remove them. |
| March | First nematode dose once the soil is above 5C. Set beer traps. |
| April | Slug season gets going. Hunt by torchlight twice a week. |
| May | Cover new seedlings. Raise pots on feet and clear hiding places. |
| June | Keep beer traps topped up. Scatter a few pellets if damage is bad. |
| July | Quieter in dry weather. Water in nematodes if rain returns. |
| August | Second nematode dose. Protect your strawberries. |
| September | Autumn slug rush. Back to evening hunts. |
| October | Clear fallen leaves around plants at risk. |
| November | Things slow down. Leave log piles for slug-eating wildlife. |
| December | Plan for next year and order nematodes for March. |
Copper tape on a pot rim won’t do much alone. Raise the pot off the ground and check it on damp evenings too.
Common slug control mistakes
Sticking to one method
Nothing works on its own. Mix nematodes, evening hunts, a few pellets when needed, tidy habits, slug-proof plants and plenty of wildlife.
Using salt
Salt harms earthworms, soil life and plant roots. Keep it out of the garden.
Putting nematodes on dry soil
Nematodes need moist soil to move about. Water well before and after, and keep the soil moist for two weeks.
Giving up too early
Slug control is a season-long job, not a one-off. Keep going and it gets easier.
Killing the helpful ones
Leopard slugs and large black slugs mostly eat rotting matter, and leopard slugs eat other slugs. Leave them be and focus on the small grey ones.
Slug control methods at a glance
Here’s a quick guide to what’s worth your time and what isn’t.
| Method | Worth it? | Effort | Best for |
|---|---|---|---|
| Nematodes (Nemaslug etc.) | Yes | Easy | Whole garden, slugs underground |
| Evening hand-picking | Yes | Some effort | Favourite beds, quick results |
| Wildlife | Yes | Easy | Long-term help |
| Beer traps | Somewhat | Some effort | Small beds |
| Grapefruit or melon traps | Somewhat | Some effort | Gathering slugs up |
| Cloches and bottle covers | Somewhat | Easy | New seedlings |
| Companion planting | A little | Easy | Making beds less tempting |
| Copper tape or mesh | Not really | Easy | Pots, as a small extra |
| Wool pellets | Not really | Some effort | Not worth relying on |
| Coffee grounds | Not really | Some effort | Better on the compost heap |
| Eggshells | No | Easy | Better on the compost heap |
| Grit or gravel | No, as a barrier | Some effort | Drainage instead |
| Garlic spray | No | n/a | Not authorised, don’t use |
The winning mix: nematodes in moist soil, evening hunts and, if damage is bad, a few ferric phosphate pellets. Add raised pots, fewer hiding places, slug-proof plants and a welcome for frogs, hedgehogs, beetles and thrushes.
Slug myths to skip
There’s a lot of slug advice online, and plenty of it doesn’t hold up.
Eggshells
Slugs glide right over crushed eggshells. Their slime protects them. Save your eggshells for the compost heap.
Salt
Salt damages roots, kills earthworms and can spoil a patch of soil for months. Never use it in the garden.
WD-40 and petroleum products
Spraying WD-40 around pots is a popular online hack. It isn’t meant for garden use, can harm insects and leaves residue on food crops. Avoid it.
Vaseline on pot rims
A band of Vaseline makes a pot rim slippery, but it soon gets dirty and stops working. Raising pots on feet and checking them on damp evenings does more.
Garlic spray
Home-made garlic spray isn’t an authorised plant protection product in the UK, so it isn’t legal to use it against slugs. Stick to nematodes, hand-picking and a few ferric phosphate pellets.
Seaweed mulch
Seaweed is sometimes suggested because it’s salty. Once the rain washes the salt off, it can give slugs a nice damp place to hide.
Designing a slug-resistant garden
A few changes to your garden’s layout can cut slug trouble for years.
Raised beds and containers
Raised beds and pots make slugs easier to manage. Plants are at a handy height for torchlight checks, and clear edges leave slugs fewer places to hide. Pots on feet, benches or shelves are harder for slugs to reach.
When you build a new raised bed, line the base with fine mesh and fill it with bought compost, not garden soil, which can carry slug eggs.
Gravel and open ground
Slugs prefer soft, damp surfaces. A gravel path or a 30cm strip of gravel around a bed gives them a dry zone they tend to avoid, except in very wet weather. Use washed gravel rather than fine grit, which packs down and holds water.
Plant spacing and airflow
Crowded plants keep the ground shady and damp, which slugs love. Space plants for their full grown size so air can move between them. This matters most for lettuce, hostas and other slug favourites.
Growing upwards
Lift slug-prone crops out of reach. Try strawberries in hanging baskets, lettuce in wall planters, or herbs on a shelf. Climbing beans, peas on supports and staked tomatoes all keep the crop up off the ground.
For more ways to build a naturally healthy plot, see our guide to companion planting for UK gardens.
A board laid on the soil makes an easy slug trap. Lift it in the morning and clear out what’s hiding underneath.
Frequently asked questions
What is the most effective natural slug control?
Nematodes, backed up by evening slug hunts. Water them into moist soil once it’s above 5C, usually from March. They hunt slugs under the ground, and one dose protects for about six weeks. Add torch-lit hand-picking on damp evenings to catch the slugs above ground.
Do coffee grounds deter slugs?
Not reliably. Any effect fades quickly as the grounds dry and break down. Pop them on the compost heap instead, and rely on nematodes, evening hand-picking and a few ferric phosphate pellets if needed.
What plants do slugs hate?
Plants with tough, hairy or strongly scented leaves. Ferns, hardy geraniums, astilbes, foxgloves, lavender, rosemary and euphorbia are all good choices. If you love hostas, thick-leaved ones like ‘Sum and Substance’ cope much better than thin-leaved types.
Do beer traps work for slugs?
Yes, but only for a small patch around each trap. Sink a pot so the rim sits level with the soil and fill it with cheap beer. Empty and refill every two or three days. They help as part of a mix of methods but won’t protect a whole garden.
How do I protect hostas from slugs?
Grow them in pots raised off the ground. Stand them on pot feet or a bench, away from damp hiding places. Choose thick-leaved types like ‘Sum and Substance’ or ‘Halcyon’. Water nematodes into the soil around them in March and August, check with a torch on damp evenings, and scatter a few ferric phosphate pellets if damage is bad.
When are slugs most active in the UK?
On mild, damp evenings from April to October. They feed most from dusk to around midnight. They slow down in cold weather, in dry spells and in hot weather. Rain after a dry spell brings them out in force.
Do eggshells stop slugs?
No, slugs slide straight over them. Copper tape, wool pellets and grit don’t do much better either. Put your eggshells on the compost heap and use nematodes, evening hand-picking and a few ferric phosphate pellets instead.
How do I slug-proof a raised bed?
You can’t make it fully slug-proof, but you can help a lot. Fill a new bed with bought compost, as garden soil can carry slug eggs, and line the base with fine mesh. Keep the edges clear of weeds, boards and clutter. Water in nematodes when the soil is mild and moist, and hand-pick on damp evenings.
Our team produces practical UK gardening guidance from source research, contributor records and established horticultural practice. Editorial standards are overseen by Matt W.
