Global: Curing at 10–15 °C for Up to Three Weeks Prepares Potatoes for Long Storage
Key takeaways
- 10-12 °C for 10-14 days is a current Canadian curing advice
- 95% relative humidity is the usual target during curing
- 55-70% of storage weight loss occurs in the first month
- 5% weight loss after five months was seen in Idaho stores
Why it matters
- For farmers
- Harvest at 10–16 °C pulp temperature, then hold stores at about 10–13 °C and 95% humidity with steady air flow for the first two weeks.
- For processors
- Ask suppliers for curing records and pile temperatures; poorly cured lots carry more shrink and rot risk into the season.
- For suppliers
- Storage firms can offer humidification and cooling capacity sized to bring warm crops down within days, not weeks.
60-second summary
The first weeks in store decide much of the shrink a potato pile will suffer, which is why advisers stress curing. Guidance from Canadian and Californian sources sits between 10 and 15 degrees with humidity near 95 percent, held for roughly 8 days to three weeks depending on crop and maturity. University of Idaho measurements reported in 2017 found that 55 to 70 percent of all weight loss happened within the first 30 days, about 3 percent in month one and about 5 percent after five months. Harvesting at a pulp temperature of 10 to 16 degrees helps, since warm tubers invite rots and lose more water while cooling, and a slow store may need over two weeks to bring 21-degree potatoes down. Store managers, growers with on-farm storage and processors buying stored crops are most affected. The caveat is that the ranges come from different regions and varieties, so local advice should prevail.
Freshly harvested potatoes carry cuts, scrapes and bruises. Before long storage, these wounds need to heal. The process is called curing. It takes place in the store during the first weeks after harvest.
Recommendations differ slightly, but they fall in a narrow band. Ryan Barrett, research and agronomy specialist with the PEI Potato Board in Canada, advised in Spud Smart on 17 September 2026 to hold tubers at 10 to 12 °C for at least 10 to 14 days. He called for high relative humidity and plenty of air flow.
A Spud Smart report from January 2025 cited two further ranges. One source recommended 95% humidity and 11 to 13 °C during the first two to three weeks. Another said curing at 13 to 14 °C promotes cell repair and reduces respiration losses. The same report noted that respiration is lowest at 7 to 10 °C.
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For early-crop potatoes, the University of California, Davis, gives a warmer regime. Its fact sheet by Trevor Suslow and Ron Voss recommends 8 days at 15 °C and 95% humidity. This allows storage for up to 5 months at 4 °C.
Most weight loss comes early
Curing matters because losses peak at the start. University of Idaho researchers measured weight loss in commercial stores with sample bags, Spud Smart reported in 2017. Between 55 and 70 per cent of total loss occurred in the first 30 days. About 3% of weight was lost in the first month. Total loss after five months was about 5%.
Start with the right pulp temperature
Curing works best when tubers enter the store in good condition. Barrett recommends harvesting at pulp temperatures between 10 and 16 °C. Warm tubers are prone to soft rot, Pythium leak and pink rot. They also lose more weight while they cool.
Cooling capacity can be a bottleneck. According to the 2025 report, potatoes entering at 21 °C can take more than two weeks to reach target temperature in an underperforming store. Mature tubers need less curing time than immature ones.
Why it matters
A tonne of potatoes lost to shrink is a tonne that cannot be sold. With 3% lost in the first month, a two-week curing phase done well protects much of the stored value. Healed wounds also give storage pathogens fewer entry points later in the season.
Photo: A potato store in Ylöjärvi, Finland, 1962 (illustrative). Erkki Voutilainen / Wikimedia Commons, CC BY 4.0
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Sources
- Spud Smart (R. Barrett, PEI Potato Board), Prioritizing Tuber Quality Amid a Hectic Harvest, 17.09.2026 — https://spudsmart.com/prioritizing-tuber-quality-amid-a-hectic-harvest/
- Spud Smart (M. Zienkiewicz), Storing Potatoes: How to Manage Your Investment Under the Roof, 23.01.2025 — https://spudsmart.com/storing-potatoes-how-to-manage-your-investment-under-the-roof/
- Spud Smart, Managing Weight Loss in Storage (University of Idaho data), 17.11.2017 — https://spudsmart.com/managing-weight-loss-storage/
- UC Davis Postharvest Technology Center (T. Suslow, R. Voss), Potato — https://postharvest.ucdavis.edu/produce-facts-sheets/potato
Linked in this material
- Country
- Global
- Technologies
- curing; wound healing; storage ventilation
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