As we creep towards strawberry planting season on the Central Coast, it is always good to review where we stand currently on nursery cold conditioning, and with this in mind, think about adjustments to the post harvest supplementary chill based on what sort of winter we might be expecting.
Those of you who know me understand my faith in hedging my bets and planning for contingencies. I favor decisions with a high probability of success and decent outcomes over swing for the fences with blow your socks off results but missing and failing most of the time. Short supplemental chill times with early planting dates to get the beat on the competition are not my thing since this strategy puts good plant vigor at risk, especially if this 2017-18 winter is warm.
Chill accumulation for this year looks good at the nurseries up at MacDoel. Using Lassen Canyon Nursery's chill accumulation chart (also appreciate the comps to previous years- very useful), shows that, after a warm start in September, hours have really ramped up and currently as of October 5 we are at 337 total hours according to my Utah model calculations (which subtracts chill during warm weather episodes, and discounts temperatures under freezing - look elsewhere on this blog for how I am doing this). That compares very well with previous years, and is in fact ahead of many of them.
Further, looking forward to what sort of winter we are to expect, let's go to the NOAA weather maps. Quite simply, for all of our strawberry production areas, it is as of now 40% probable that we get temperatures above normal this winter (being December, January and February). This is up from 33% a few weeks ago, so I am sensing a trend which seems to confirm where we are headed.
http://www.cpc.ncep.noaa.gov/products/predictions/long_range/lead03/off03_temp.gif
In conclusion, with solid field chill already in the can but a good probability of a warmer than normal winter in the offing, I would again this year favor just a little bit more supplemental chill than customary.