Chill hours are a primary factor in determining how well plants will emerge from dormancy – impacting bud break for both blooms and leaves. Delayed emergence can create management issues for growers like increased labor costs for pruning and a longer pollination window delaying crop maturity. Higher temperatures, lack of cloud cover, and microclimates in the topography of farmland can all contribute to a shortfall in chill. The weekly California Chill Hour Report will feature UC researchers and other experts and industry members highlighting the progress of chill accumulation and how crops might best be managed under those conditions.
In reviewing information from the UC Davis Chill Calculator, as of December 6, the Durham CIMIS station registers 23 cumulative portions under the dynamic model, with 461 total hours below 45°F. In Holt, the CIMIS station has recorded 21.6 cumulative portions, with 396 chill hours. There have been 401 chill hours in Five Points, with 20.5 cumulative portions. In Paso Robles, there have been 481 chill hours, equating to 22 cumulative portions. There has been a total of 381 hours in Shafter, registering as 20.5 cumulative portions under the dynamic model. Finally, the CIMIS station at UC Riverside has only registered 10.8 cumulative portions, with 70 total chill hours.
While at the Almond Conference this week, we had the opportunity to speak with the Director of Sales and USA Agriculture for Alzchem, John Meyer. In talking about the importance of chill hours for optimal crop growth, Meyer explained that a bud-breaking agent like Dormex could provide some needed support for when chill is insufficient. Meyer said he saw quite a bit of success in a California almond trial in the Madera area this past year.
“Typically, with an almond application you want to spray 30 days before anticipated bud break,” Meyer noted. “[The grower] got additional lateral bud development and it was reduced apical dominance. It turned out to be a very nice trial….those lateral buds were growing even more so than the untreated part of the trial. So, it was very impressive.”
Listen to the segment below.