Cranberry growers in Southeastern Massachusetts have faced weather whiplash this year. A spring drought gave way to record rainfall in July. Next up: an August heatwave.
With 90-degree temperatures expected along the South Coast this week, farmers will keep their berries cool with short bursts of irrigation in the warmest part of the day, according to Hilary Sandler, the director of the UMass Cranberry Station in Wareham.
“It’s kind of like when you jump into a swimming pool, you can cool off for a little while, because you get that evaporative cooling off your skin,” said Sandler. She added that, while the leaves of cranberry bushes can transpire to keep cool, the berries themselves have no such adaptations. Extreme heat can harm cranberries’ development.
“Since the cranberries are grown in a depression in the landscape, they tend to either be hotter than ambient or colder than ambient temperatures,” said Sandler. “So if it's 80 degrees ambient, it could be 95 or 100 or 105 in the canopy on the fruit.”
Looking ahead, Sandler said cool nighttime temperatures in August and September are ideal to help cranberries develop a deep red hue prior to harvest.
But climate change is making those crisp conditions harder to come by.
“That's really the thing that causes us the most worry is that we really need those cool temperatures to get the color,” said Sandler. “Growers can't deliver their fruit until their fruit pass a certain threshold of having that red pigment.”
