PEST GUIDE
How to identify and manage snails
Irregular holes and ragged young leaves, often after damp nights. Identify the cause, protect the listed crops and use proportionate control.
13 sections
Identification
Snails shelter under boards, pots and dense foliage during daylight. They leave ragged holes and slime trails, but those signs overlap with slug damage; inspect after dark to confirm whether shells are present.
Shelled molluscs hide under cover and leave shiny slime trails.
Look for a shell when you check after a damp evening, then inspect beneath pots and boards where snails shelter by day. Similar symptoms can come from weather, nutrient stress or another pest. Confirm fresh feeding or the relevant life stage before removing plants or taking control measures.
UK seasonality and monitoring
Snails are active on mild, damp nights from spring to autumn.
During this period inspect Salads, brassicas, strawberries and seedlings, concentrating on the crop stage and plant parts described above. Note when and where fresh injury appears; old feeding marks can remain after the pest has moved on.
Crops and plants affected
The recorded hosts are Salads, brassicas, strawberries and seedlings. This list identifies plants worth checking; it does not mean every crop is equally vulnerable. Start with the listed plants and inspect the tissue where this pest feeds.
Check affected crops for these signs: Irregular holes and ragged young leaves, often after damp nights. Match the symptom to a live pest, larva, egg or characteristic feeding sign before deciding that treatment is needed.
Damage and likely consequences
Irregular holes and ragged young leaves, often after damp nights. A small amount of old damage on a vigorous plant may be cosmetic. Continued feeding on roots, seedlings, growing points or edible parts can reduce establishment or yield.
On Salads, brassicas, strawberries and seedlings, judge severity by checking whether injury is fresh and spreading, whether the plant is still growing, and whether the edible part is affected. Avoid removing a crop based on one ambiguous mark.
Prevention
Remove hiding places beside seedlings, inspect after damp nights and raise vulnerable plants where practical.
Control and integrated management
Hand-pick confirmed snails and use barriers around the most vulnerable plants, checking underneath for shelter.
Natural predators and wildlife-conscious choices
Accept some grazing and avoid blanket molluscicide use.
For snails on Salads, brassicas, strawberries and seedlings, use a barrier or hand removal only where it fits the crop and life stage. Keep any cover taut, inspect it for trapped wildlife, and remove it when protection is no longer needed.
Long-term management
Encourage thrushes, frogs and beetles and accept light grazing on established plants where the crop can tolerate it.
For snails on Salads, brassicas, strawberries and seedlings, record the bed, crop stage and date when fresh damage first appears. Those notes help time protection and monitoring before the same crop stage is vulnerable next season.
Common mistakes
A symptom alone is not a diagnosis. Snails shelter under boards, pots and dense foliage during daylight. They leave ragged holes and slime trails, but those signs overlap with slug damage; inspect after dark to confirm whether shells are present. Look for a matching live pest or fresh feeding sign before intervening.
Many snails feed on decaying matter; occasional holes do not justify blanket molluscicide use.
If damage continues
Recheck Salads, brassicas, strawberries and seedlings where new injury is appearing, including the hidden feeding site: roots, folded leaves, leaf undersides, flowers or fruit as appropriate. If identification remains uncertain, photograph a live specimen alongside the damage and ask an allotment association or horticultural adviser.
If the recommended control (Hand pick, use barriers and encourage thrushes, frogs and beetles.) has not helped, confirm that it was fitted or applied at the right crop stage and that fresh damage is still occurring. Old marks do not heal when the pest has gone.
Frequently asked questions
How can I distinguish snail damage from slug damage?
Snails shelter under boards, pots and dense foliage during daylight. They leave ragged holes and slime trails, but those signs overlap with slug damage; inspect after dark to confirm whether shells are present. Check Salads, brassicas, strawberries and seedlings, especially at the feeding site described above. Hand pick, use barriers and encourage thrushes, frogs and beetles.
When should I start checking for snails?
Snails are active on mild, damp nights from spring to autumn.
How can I tell whether snails are still active?
Look for fresh damage and the relevant life stage. Irregular holes and ragged young leaves, often after damp nights. Old marks may remain after the pest has moved on.
What wildlife-conscious approach works for snails?
Accept some grazing and avoid blanket molluscicide use. Check covers and traps frequently, and remove them when the vulnerable crop stage has passed.