What Is Eating My Cucumber Seedlings?

Few setbacks sting like raising cucumber seedlings only to find them chewed to stubs, cut off at the base, or vanished entirely overnight. Young cucumber seedlings are tender, defenceless and irresistible to several common pests, and because they are so small, the damage can be fatal fast. Identifying the culprit quickly lets you protect the survivors and any replacements. Let me walk you through the usual suspects and how to tell them apart.

Slugs and snails

The most common seedling-killers are slugs and snails. If your seedlings have ragged holes, are stripped of their soft leaves, or have disappeared entirely, and you find silvery slime trails on the soil or nearby in the morning, these are your culprits. They feed at night and in damp weather, and they can clear a row of cucumber seedlings in a single night. Go out after dark with a torch to confirm and hand-pick them, set beer traps, clear damp hiding places, and ring the seedlings with a gritty barrier like crushed eggshell or grit that they dislike crossing.

Cutworms

If seedlings are found cut off cleanly at or just above the soil line, toppled over as if snipped with scissors, the culprit is the cutworm. These soil-dwelling caterpillars hide just below the surface by day and emerge at night to chew through tender stems at ground level. They are devastating to young transplants. The classic defence is a collar around each seedling — a cardboard tube or a cut plastic cup pushed an inch into the soil — which physically blocks the cutworm from reaching the stem. Clearing weeds and disturbing the soil before planting reduces them too.

Cucumber beetles and other chewers

Cucumber beetles attack seedlings too, and they are especially dangerous because they can transmit bacterial wilt to a young plant that may not survive the infection. If you see small striped or spotted yellow beetles and chewed holes in the seedling leaves, protect plants urgently with row cover and control the beetles. Various other beetles and caterpillars will also nibble seedlings. Birds occasionally pull at seedlings as well, and earwigs can chew the soft growth at night.

Protecting young cucumbers

The single best protection for vulnerable seedlings is a physical barrier. Floating row cover laid over the seedlings keeps out beetles, and to some extent other pests, while letting in light and water — just remove it once plants flower so pollinators can reach them. Cloches or cut-bottle covers protect individual plants from slugs and cutworms alike. Starting seeds in pots and transplanting slightly larger, sturdier plants, rather than sowing tiny seedlings straight into pest-prone ground, also helps them survive the danger period.

Identify, then defend

Match the damage to the pest: ragged holes and slime equals slugs and snails — hunt at night and set barriers; clean-cut toppled stems equals cutworms — use collars; small holes with yellow beetles equals cucumber beetles — cover and control urgently. Then protect the rest with row cover or cloches through the seedling stage. Cucumbers grow fast once established, so if you can shepherd them safely through those first vulnerable weeks, they soon become tough enough to shrug off most of what threatened them as seedlings.