Even in the northern corners of the U.S., growers are experiencing the effects of climate change. Consecutive years of spring heat waves, combined with long dry periods, have recently challenged Michigan blueberry growers with diminished blueberry yields.
It’s not the first time in recent memory that such conditions have hindered the state’s blueberry crop.
In both 2018 and 2022, drought conditions in the Great Lakes State reduced blueberry yields as much as 40%, according to Michigan State University Extension.
In another instance, during the critical early months of February through March 2012, temperatures were the highest on record since 1880 according to NOAA. These unseasonably high temperatures speed blueberry growth by three weeks, which leads to compounding issues of exposing tender blueberry bushes to frost damage and pollinator activity, according to a news release.
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Michigan is not alone in facing these challenges; heat domes and early spring impacts have affected cultivation in the Pacific Northwest in recent years as well.
Exploring new ways to grow blueberries in warming weather
As temperatures seem likely to creep higher in the coming years, MSU graduate students are seeking ways to cultivate blueberries that adapt to the changing climate. University researchers Jenna Walters and Rufus Isaacs recently developed a strategy to cool blueberries with overhead irrigation, like misters cooling crowds on a sweltering summer day, to protect blueberry blooms from extreme heat injury, according to the release.
While blueberry germination drops when temperatures climb above 90 degrees in common varieties like bluecrop, elliott and jersey, MSU researchers recently confirmed that heat can be effectively reduced on blueberry bushes using sprinkler mist.
The fine spray of water around the bushes essentially creates a microclimate that favors fruit growth and encourages better pollination conditions. In MSU research trials, running overhead irrigation reduced the air temperatures as much as 5 degrees to 10 degrees, according to the release.
Following an approach developed by Oregon State University to chill summer fruit, cooling blueberry bushes with sprinklers kept the air temperatures below 90 degrees throughout even the warmest times of day, the release said.
One factor to consider with irrigation includes the risk of disease from applying water. That can be mitigated by using a post-irrigation fungicide application, according to the release.
