Troubleshooting
Spaghetti Squash problems — and how to fix them
Spaghetti Squash (Cucurbita pepo 'Spaghetti') 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.
Powdery mildew
Appears as a white dusty coating on foliage, especially in late summer. A degree of infection is normal at the end of the season. Apply potassium bicarbonate or sulfur fungicide at first appearance and choose resistant cultivars like 'Tivoli'.
Poor fruit strand development
Flesh that doesn't separate into strands usually results from harvesting too early. Harvest only when rind is fully pale yellow and resists puncture with a fingernail. Cure at room temperature for 1–2 weeks post-harvest.
Squash vine borer
A major pest in eastern North America. Use floating row covers until first female flowers open, plant a second sowing in early July to escape the peak borer flight, and check vine bases weekly for frass (sawdust-like excrement).
Prevent spaghetti squash problems before they start
Most spaghetti squash issues are care-mismatch, not bad luck. Dial in the basics:
- Common squash problems — the species this cultivar belongs to
- Common spaghetti squash problems — our other guide for the same plant
- What's wrong with my plant? — the diagnosis apps compared
- Spaghetti Squash watering schedule
- Spaghetti Squash light requirements
- Best soil mix for spaghetti squash
- Spaghetti Squash temperature & humidity
- Full spaghetti squash care guide
Looking for spaghetti squash in general rather than its problems? Read the full spaghetti squash care guide — light, water, soil and feeding.
Spaghetti Squash problems — FAQ
Why is my spaghetti squash powdery mildew?
Appears as a white dusty coating on foliage, especially in late summer. A degree of infection is normal at the end of the season. Apply potassium bicarbonate or sulfur fungicide at first appearance and choose resistant cultivars like 'Tivoli'.
Why is my spaghetti squash poor fruit strand development?
Flesh that doesn't separate into strands usually results from harvesting too early. Harvest only when rind is fully pale yellow and resists puncture with a fingernail. Cure at room temperature for 1–2 weeks post-harvest.
Why is my spaghetti squash squash vine borer?
A major pest in eastern North America. Use floating row covers until first female flowers open, plant a second sowing in early July to escape the peak borer flight, and check vine bases weekly for frass (sawdust-like excrement).