Yes, leaving potatoes in the ground too long can cause significant problems. Once potatoes reach full maturity with proper skin set, they should be harvested promptly to avoid quality deterioration and increased risk of damage.
Problems from delayed harvest:
According to CIP and university extension research, overmature potatoes develop several issues. The tubers become more susceptible to mechanical damage during harvest because they grow larger and the skin may become tougher but more brittle. Extended time in soil also increases exposure to soil-borne diseases and pests that can cause rot or damage during storage.
Temperature-related risks are particularly severe. FAO data shows that tubers are damaged below -1°C, developing soft, blackened zones inside that render them unusable for consumption or processing. Even without frost, fluctuating soil temperatures can stress tubers and reduce their storage potential.
Timing varies significantly by intended use. USDA and extension guidelines show that new potatoes should be harvested at 60-75 days before skin set for premium tenderness and immediate consumption. Fresh storage potatoes need full maturity plus skin set, while processing potatoes require full maturity with high dry matter content and low reducing sugars. Seed potatoes should reach full maturity with skin set, though some growers harvest slightly early to reduce tuber-transmitted disease incidence.
The key is monitoring soil conditions and weather forecasts once potatoes reach maturity, as prolonged exposure to adverse conditions can quickly compromise quality and storage life.