Our employee daily meeting this morning was cold—very cold (for a California girl)! As I watched the fog roll in, our employees bundled in heavy jackets and beanies, and the temperature reading 36 degrees, I felt grateful for a cold, foggy and rainy winter.
As I have now been farming with my family for almost seven years, I have come to better understand how important these winter months are for many fruit and nut trees to accumulate their required chill hours (generally calculated as temperatures between 32°-45° Fahrenheit).
These trees need the winter months to store energy in order to get ready for bud development and flower growth. This is one reason we can’t grow many of these nut and fruit trees in tropical or warm climates, it simply doesn’t get cold enough to allow the trees to go dormant.
Last year bloom in the almonds had already begun with only 418 chill hours accounted for in Colusa County. As of today we have 790 chill hours accumulated this year—that is almost twice as many chill hours this year than when almond bloom started last year and much closer to the number of hours that UC Davis calculates that most fruit and nut trees in our area need by the start of their bloom period.
While crops were good for most fruit and nut trees in our area last year, indicating they received a sufficient number of chill hours, we know it was a close call. While almonds, depending on the variety, need around 400 chilling hours, our Howard walnuts and freestone peach varieties require more—around 800 (but they have a little more time to accumulate them as bloom starts later).
As I watch a beekeeper placing hives outside my window right now, indicating the beginning of almond bloom, I am ready for warmer weather and hope the chance of freezing temperatures is behind us. However, it is comforting to know that the trees have had the chill hours needed to wake up from their winter nap hopefully ready for a strong bloom and great fruit set.