Mar 16, 2020Considerations presented for study of cold hardiness in blueberries
For several years, the Washington Blueberry Commission has funded Washington State University and Oregon State University research to collect bud hardiness data and create a model. Our research team is still in the process of developing the model but we do collect, freeze, and cut buds to assess mortality of individual flower initials. Below is the data for lethal temperatures. Important considerations when looking at the numbers are:
- Date assessed: We will send updates again with recent data. If your buds have progressed in development since our date of assessment, the buds will be less cold hardy.
- AWN Station: This is the closest weather station to the fields in which buds were collected. Preceding and local temperatures are critical in the level of cold hardiness. Assess if your site is cooler or warmer than the station listed here. Warmer sites will likely be less cold hardy with possibly more advanced buds.
- Stage: Phenology is critical to the level of cold hardiness. In almost every year of our research, we have documented that buds in ‘bud swell’ will reacclimate very quickly to cold weather.
- LT 10˚ F: This is the Lethal Temperature in which 10% of the floral initials will die. This can vary by cultivar, site, temperatures, and stage.
For more information:
- AgWeatherNet (http://weather.wsu.edu/) has grape and cherry cold hardiness models. Log on and go to crop models.
- Blueberry concerns
- Eastern WA, Gwen Hoheisel ([email protected])
- Western WA, Lisa DeVetter, Lisa Wasko ([email protected])
Michigan Cold Hardiness Bud Chart (https://www.canr.msu.edu/blueberries/growing_blueberries/growth-stages