Troubleshooting
Jack-o-Lantern Pumpkin problems — and how to fix them
Jack-o-Lantern Pumpkin (Cucurbita pepo 'Jack-o-Lantern') 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.
Undersized fruit
Too many pumpkins per plant stay small; thin to two or three fruits per vine for full-sized carving pumpkins.
Powdery mildew
White coating on the broad leaves by late summer; improve airflow and water at the base rather than overhead.
Rotting on damp ground
Fruit in contact with wet soil can rot from below; rest each pumpkin on a tile, board or straw as it grows.
Stem-end rot in store
Cutting too close to the fruit shortens storage; leave a 5-10 cm stalk and harvest before the first hard frost.
Prevent jack-o-lantern pumpkin problems before they start
Most jack-o-lantern pumpkin issues are care-mismatch, not bad luck. Dial in the basics:
- Common squash problems — the species this cultivar belongs to
- What's wrong with my plant? — the diagnosis apps compared
- Jack-o-Lantern Pumpkin watering schedule
- Jack-o-Lantern Pumpkin light requirements
- Best soil mix for jack-o-lantern pumpkin
- Jack-o-Lantern Pumpkin temperature & humidity
- Full jack-o-lantern pumpkin care guide
Looking for jack-o-lantern pumpkin in general rather than its problems? Read the full jack-o-lantern pumpkin care guide — light, water, soil and feeding.
Jack-o-Lantern Pumpkin problems — FAQ
Why is my jack-o-lantern pumpkin undersized fruit?
Too many pumpkins per plant stay small; thin to two or three fruits per vine for full-sized carving pumpkins.
Why is my jack-o-lantern pumpkin powdery mildew?
White coating on the broad leaves by late summer; improve airflow and water at the base rather than overhead.
Why is my jack-o-lantern pumpkin rotting on damp ground?
Fruit in contact with wet soil can rot from below; rest each pumpkin on a tile, board or straw as it grows.
Why is my jack-o-lantern pumpkin stem-end rot in store?
Cutting too close to the fruit shortens storage; leave a 5-10 cm stalk and harvest before the first hard frost.