Cooperative Extension Farm Advisor Janet Caprile says some complications were seen last year with bud break in walnuts. “We don’t exactly know why but there is conjecture that when you have a nice dark branch, in the winter time it gets hot in the daytime and cold at night,” Caprile says. “There is evidence that the fluctuation in temperature on the trunk is what really causes the buds to start mobilizing, the carbohydrates start to come up through those buds and the buds start to push.”
Caprile says a combination last year led to less of a temperature variance and applying a white paint to trees in a year that is forecast with low-chill may not be the best idea. “Last year we had such low chill that we had a problem with bud break anyway,” Caprile says. “On those trees that were painted white, they just weren’t getting the temperature fluctuation that was needed and so we saw a lot of buds that just didn’t break.”
Caprile added that they did not see the same results the previous year with painted trees but chilling hours were much more frequent that winter.