We are finally getting some much needed rain, though total amounts varied widely throughout the growing region. Depending on the path of Hurricane Matthew, the area could receive even more rain this weekend. September weather report has been posted on the web site. http://ag.umass.edu/cranberry/weather-summaries.
A note from Carolyn concerning frost tolerance of fruit: If we have temperatures that are right at tolerance, the berries can tolerate at the threshold temperature for a couple of hours without frost protection. So if the tolerance is met around 3-4 am, chances are good that you can avoid injury and not run your sprinklers. Of course, if the temperature goes below tolerance, all bets are off and you must protect. We don’t have any photos specifically from this year, but there are good photos showing the progression of fruit color and tolerance from past years on the web site at: http://ag.umass.edu/cranberry/frost-tolerance-reports.
Some growers are concerned about the lack of color development so far. Color is triggered both by day length and minimum (nighttime) temperatures. If we can get more nights in the 50s or lower, the color should proceed along (somewhat normally). Color may also be slowed since the vines have been under physiological stress due to the dry, drought conditions prevalent throughout the growing season.