- Author: Mark Bolda
People who care about chill might want to spend a moment on this as the article linked below refers to different qualities of environmental chill.
The following article is for pistachios, but conceptually the thesis applies to our berry culture on the Central Coast.
One to two decades ago, fog in the Central Valley maintained temperatures steady, oftentimes below the 45 degree threshold for chill accumulation, for longer periods. This has been named "warm-wet" chill.
In recent years, however, the pattern has changed, to little fog and consequent cold nights below 45 degrees followed by clear sunny days well into the sixties. Net result of this "sunny chill" has been buds breaking on the sunny side of the tree and no buds breaking on the shady side. A comparison in strawberry would be more pronounced differences in plant performance on the warm side of the bed compared to the cooler; caneberries quite probably similar to trees in having lateral budbreak earlier on the side of the hedgerow facing the Sun.
Now, in 2016-17, it's even more complicated with warm rains and few days below 45 degrees at all. Doesn't seem like there is a consensus on how this will play out in the spring.
H/T Bob Klein, Manager; Administrative Committee for Pistachios and UCCE Farm Advisor Craig Kallsen.