Troubleshooting
Cipollini Onion problems — and how to fix them
Cipollini Onion (Allium cepa 'Cipollini') is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Premature bolting
Cold snaps below ~10C after transplanting trigger flower stalks, splitting the bulb and ruining storage. Plant correctly sized sets and avoid setting out oversized transplants too early.
Onion neck rot
Botrytis enters poorly cured, thick-necked bulbs and turns the top into soft brown mush in storage. Cure thoroughly for 2-3 weeks and stop nitrogen feeding once bulbing begins.
Onion downy mildew
Pale, elongated patches and grey-violet fuzz appear on leaves in cool, humid weather, stunting bulbs. Space for airflow, water at the base, and rotate alliums on a 3-year cycle.
Onion fly (maggot) damage
Larvae tunnel into the base, wilting young plants and rotting bulbs. Use insect-mesh covers at emergence and avoid planting into freshly manured ground.
Prevent cipollini onion problems before they start
Most cipollini onion issues are care-mismatch, not bad luck. Dial in the basics:
Looking for cipollini onion in general rather than its problems? Read the full cipollini onion care guide — light, water, soil and feeding.
Cipollini Onion problems — FAQ
Why is my cipollini onion premature bolting?
Cold snaps below ~10C after transplanting trigger flower stalks, splitting the bulb and ruining storage. Plant correctly sized sets and avoid setting out oversized transplants too early.
Why is my cipollini onion onion neck rot?
Botrytis enters poorly cured, thick-necked bulbs and turns the top into soft brown mush in storage. Cure thoroughly for 2-3 weeks and stop nitrogen feeding once bulbing begins.
Why is my cipollini onion onion downy mildew?
Pale, elongated patches and grey-violet fuzz appear on leaves in cool, humid weather, stunting bulbs. Space for airflow, water at the base, and rotate alliums on a 3-year cycle.
Why is my cipollini onion onion fly (maggot) damage?
Larvae tunnel into the base, wilting young plants and rotting bulbs. Use insect-mesh covers at emergence and avoid planting into freshly manured ground.