In the December issue of the Badger Common’Tater magazine out of Wisconsin in the US, an article is featured in which specialists Paul Bethke and Troy Fishler tackle the matter of frost-damaged potatoes.
Bethke is with the U.S. Department of Agriculture and University of Wisconsin-Madison Department of Horticulture, and Fishler is research manager, Wisconsin Potato & Vegetable Storage Research Facility, Hancock Agricultural Research Station.
Rain and cold delayed potato harvest throughout Wisconsin in 2018. Many farms were still digging potatoes in late October and into November, Bethke and Fishler writes.
Temperatures below freezing took a toll on numerous fields when potatoes suffered frost damage.
No one wants to see another harvest like 2018, but perhaps there is value in reviewing the causes and consequences of frost damage and discussing strategies for managing frost-damaged potatoes before we put 2018 to rest and begin making plans for 2019.
Frost damage occurs when tuber temperature drops below approximately 30 degrees Fahrenheit (F) and tuber tissues freeze.
Potatoes that are closer to the surface are more likely to experience freezing temperatures than those deeper in the soil. Green potatoes, which are at the soil surface, will undoubtedly be the first to suffer from frost damage.
Frozen potato tissue is no longer viable and cannot be healed. Rapid water loss begins as soon as the affected tubers thaw. Frost-damaged tissues develop wet patches on the skin as moisture leaks from lenticels.
Once a decision has been made to store frost-damaged potatoes, then the storage manager needs to establish priorities for stabilizing the stored material and delivering a saleable product. Bethke and Fishler suggest the highest priority should be maintaining the quality of those potatoes that have not been frozen.