How cold is too cold? MSU experts say tree fruit buds should be safe
Learn which crops MSU says are most vulnerable, what temperature thresholds matter and how to assess potential damage after the cold passes.
A notable cold snap is in the forecast this weekend across the Upper Midwest, Mid-Atlantic and the South. In some northern geographies, overnight lows will approach or even exceed -10° F.
Understandably, this has raised concerns among growers about potential winter damage to fruit buds, writes Dan Dick with Michigan State University (MSU) Extension.
However, according to this post by MSU Extension, for most fruit crops that are fully dormant, the forecasted temperatures should stay within historical tolerances and are unlikely to cause widespread cold injury.
Overall risk from cold depends on the specific crop, variety and how well hardened off the buds are heading into the cold event, Dick added.
MSU Extension shared the following approximate lethal temperature thresholds (the point at which significant bud mortality begins) for common tree fruit crops under mid-winter conditions:
- Apple: around -30° F
- Pear: around -25° F
- Tart cherry: around -20° F
- Highbush blueberry: around -25° F
- Concord grape: around -25° F
- Peach: around -13° F
- Sweet cherry: around -15° F
For more cold-sensitive crops like peaches, sweet cherries, Japanese plums and vinifera grapes, MSU says growers should continue monitoring conditions and be aware of variances in microclimates, because cold pockets in low areas may dip below the temperatures forecast by weather services.
Monitoring crop injury risk
MSU Extension emphasizes that cold injury does not happen gradually. Instead, once temperatures cross a crop’s threshold, damage can increase quickly, which makes understanding thresholds more useful than simply knowing the numeric forecast.
MSU says for this specific event, localized injury remains a possibility in the coldest pockets, particularly where cold air circulation is poor or snow cover is low. Thankfully, widespread damage is not anticipated for most fruit types under current predictions.
You can check the National Weather Service’s forecast minimum temperature maps to identify areas where forecast temperatures may approach or cross critical thresholds for a given crop, Michigan State advises.
After the arctic blast
Once this cold spell passes, growers in Michigan can compare actual minimum temperatures recorded at nearby weather stations to the fruit tolerance thresholds to gauge if any damage likely occurred. MSU’s Enviroweather system provides weather station data for this purpose.
Bottom line: while the cold front is noteworthy and worth monitoring, most fruit crops can withstand the forecasted conditions without significant cold injury — especially if buds are fully dormant and acclimated.