On the heels of the warmest February EVER in the region, March has arrived warm and with nary a single cloud.
While it’s hard to hate on surprise sun after months of clouds and drear, the unseasonable warm weather is throwing plants out of rhythm and, consequently, farmers out of whack.
Warmer temperatures and early budbreak increase the risk of frost damage for growers,” said [Lee] Kalcsits, [assistant professor of tree fruit physiology at the WSU Tree Fruit Research and Extension Center in Wenatchee]. “It could be an issue if temperatures become cold again.”
“The big message for growers is, you can’t farm by the calendar,” said Stephen Guy, a WSU Extension agronomist in Pullman. “You’ve got to farm by the temperature.”
As Guy puts it, plants don’t care whether it’s winter or spring. Temperature, not day length, is what drives plant development.
In winter, plants go dormant and harden, developing an increased tolerance for cold.
“That reaches a bottom point and starts back up again,” he said. “We’re pretty much out of that now.”
Rising temperatures bring plants out of their winter hardness and get them ready to flower. That puts crops like tree fruits and grapes at risk of a spring frost.
At Oxbow, the plum trees are in full bloom weeks early. The bees are out in the daytime, too, which is good news for the farmers–nighttime lows have been dipping below freezing. If the plum’s flowers are killed off by frost before they are pollinated, then they won’t fruit. An entire plum crop is a hefty price for a bit of February sunshine.