Slugs Eating Vegetable Plants (How to Stop Them)
You plant out a row of healthy young lettuces in the evening and by morning there are bare stalks and a few silvery trails. Slugs are the most frequently blamed creature in British gardens, and in a damp climate they're never going away entirely. The good news is that some methods genuinely reduce the damage, and RHS trials have shown that several of the most commonly recommended ones make no difference at all.
Quick answer
The methods with real evidence behind them are hand-picking on damp evenings, encouraging predators such as birds, frogs, toads and ground beetles, planting sturdy young plants rather than tender seedlings, and using nematodes in a targeted way on the beds that matter most. RHS trials found no measurable benefit from barriers of crushed eggshells, copper tape, sharp grit, bark mulch or wool pellets. Slug pellets, including organic ones, harm other garden wildlife and are best avoided.
Not all slugs eat your vegetables
This surprises most gardeners: only a small number of slug and snail species actually feed on living plants. The great majority are decomposers, breaking down dead leaves and other debris, and are doing useful work in the garden.
In a vegetable patch the offenders are mainly the netted field slug and the brown soil slug, the common garden snail, and the keeled slugs, which burrow into potatoes and other tubers.
That matters practically, because it means blanket approaches aimed at wiping out every slug in the garden are both unnecessary and counterproductive.
What's most at risk
Slugs go for soft, tender growth in damp, sheltered places. In a vegetable garden that usually means:
newly planted seedlings and transplants
lettuce and other salad leaves
young beans, courgettes and squash plants
emerging potato shoots, and the tubers themselves later on
anything growing near long grass, dense planting or the edges of raised beds
They feed mainly after dark and after rain, which is why the damage so often appears overnight.
For seedlings in particular, which are the most vulnerable stage of all, see slugs eating seedlings
Hand-picking
Unglamorous, but the single most effective thing most gardeners can do. Go out with a torch an hour or two after dusk on a damp evening, when slugs are active and out in the open, and collect what you find.
Check under leaves, around the rims and bases of pots, along the edges of beds and beneath anything lying on the soil. Rather than killing them, you can move them to a compost heap, where they'll get on with breaking down plant material.
A few evenings of this in spring, when plants are small and slugs are breeding, makes far more difference than the same effort later in the year.
Barriers: what the research found
This is where a lot of gardening advice, including the earlier version of this page, has turned out to be wrong. RHS trials compared lettuces protected by barriers with lettuces left unprotected, and found no difference in the damage between them. The barriers tested included:
crushed eggshells
copper tape
sharp horticultural grit
pine bark mulch
wool pellets
There's no harm in using them, but it's worth knowing they're unlikely to save your lettuces, and the time and money involved is better spent elsewhere.
Traps
Beer traps still have a place. Sink a container so the rim sits just above soil level, part-fill it with beer, and empty it daily. Half a scooped-out citrus skin laid cut-side down works on the same principle: slugs gather underneath overnight and you collect them in the morning.
Both need emptying and refreshing regularly to be worth anything, and they work best as a way of catching slugs near a particular vulnerable crop rather than as garden-wide control.
Nematodes
The most reliable option for a bed you really want to protect. Nematodes are microscopic organisms, watered into the soil, that kill slugs beneath the surface. They're available by mail order and applied as a drench.
Two things to know. They work only in moist soil between roughly 5°C and 20°C, so spring through to early autumn is the window. And because they kill slugs indiscriminately, including the harmless decomposers, they should be used in a targeted way on specific beds rather than across the whole garden.
Why to skip slug pellets
Slug pellets, organic ferric phosphate ones included, have been shown to harm other wildlife in the garden. Since the creatures they harm include the very predators that eat slugs, they can make the underlying problem worse over time.
Encouraging predators
A garden with a healthy population of slug-eaters has far fewer slug problems, and this is the approach that keeps paying off year after year. Ground beetles, hedgehogs, toads, frogs and birds all get through slugs in quantity.
Practical ways to encourage them:
A small pond, even a sunken washing-up bowl, brings in frogs and toads within a season or two.
Log piles, leaf litter and undisturbed corners shelter ground beetles and hedgehogs.
Gaps at the base of fences let hedgehogs move between gardens.
Bird feeders through winter keep birds visiting, and they'll take slugs in spring.
Give plants a head start
Slug damage is mostly a problem of small plants. A well-grown plant can lose a few leaves and shrug it off; a seedling loses its only leaves and dies.
So on slug-heavy ground, skip direct sowing for tender crops: start them in modules or pots and set out well-grown plants that have some substance to them. Harden them off properly first, as detailed in our hardening off guide. Choosing tougher-leaved crops and varieties for the worst-affected beds helps too.
Plants in containers tend to suffer less than those in open ground, particularly if pots are kept away from walls and dense planting. See growing vegetables in containers
Watering and tidiness
Slugs need moisture to move around. Watering in the morning rather than the evening leaves the surface drier overnight, when they're active. Water the base of plants rather than sprinkling the whole bed, which keeps the soil surface between plants drier.
Keeping the area immediately around vulnerable crops clear of long grass, weeds and old plant debris removes the daytime hiding places, though there's no need to strip the whole garden bare. Those sheltered corners elsewhere are exactly what the predators need.
Living with slugs
Every vegetable garden in Britain has slugs, and a garden with none would be an unbalanced one. The aim isn't elimination, it's keeping damage to a level you can live with: protecting the crops that are genuinely vulnerable, at the stage when they're vulnerable, and letting the rest look after itself.
Not sure slugs are to blame? Why vegetables get holes in leaves sorts out which pest leaves which damage. For wider problems, our hub page on why vegetables aren't growing is the starting point.
Common questions
What actually stops slugs eating plants?
Hand-picking on damp evenings, encouraging predators, planting sturdy young plants instead of seedlings, and targeted use of nematodes. RHS trials found barriers such as eggshells and copper tape made no measurable difference.
Do crushed eggshells and copper tape work against slugs?
RHS research found no reduction in damage from eggshells, copper tape, grit, bark mulch or wool pellets compared with unprotected plants.
When are slugs most active?
After dark and after rain, which is why damage appears overnight. The worst of it comes in spring and the first half of summer, when plants are still small and the weather is damp.
Should I use slug pellets?
They're best avoided. Pellets, organic ones included, are known to harm other wildlife in the garden, the very predators that keep slug numbers down among them.
Slug species, trial results and control methods based on RHS guidance.