2023-2024 Winter Soil Temperatures for Volunteer Potato Management

— Developed by I. Kutay Ozturk, Ph.D., UMaine Extension Potato Pathologist

Temperatures below 27°F for five days or more at 4 inches is required for efficient elimination of most volunteer potatoes.

Between 2023-2024 winter season, the soil temperatures at 6 inches in Aroostook Research Farm in Presque Isle reached below 27°F threshold for a total of 41 days, taking the average recorded soil temperatures and ignoring short dips below 27°F (excluding any timeframe below 27°F for less than 24 hours).

Conservative estimates were made by using the maximum recorded temperatures. Even with the conservative estimates, soil temperatures were below 27°F for a total of 15 days.

Overall, these indicate that the volunteer potato risk is low. However, in southern fields or in fields with different cover crops, soil temperatures might have been different, which might have aided survival of some of the volunteer potatoes.

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Average soil temperature at 6 inches: The chart above displays the average soil temperatures (°F) at 6-inches deep in the Aroostook Research Farm, Presque Isle, ME, between the dates of 9/1/2023 and 4/1/2024. A level baseline represents the threshold temperature for killing volunteer potatoes, 27°F. Throughout the last winter, soil temperatures dropped below the threshold temperature for a sufficient timeframe to allow killing majority of volunteer potatoes that were left in the field during the last harvest. Click image above to enlarge graph in a separate window. – Graphic, I. Kutay Ozturk, Ph.D.

For further information on management of volunteer potatoes, please refer to Bulletin #1090, Management of Volunteer Potatoes in Maine.