How Cold Did it Get?

In early January much of the nation was caught in the grip of a “polar vortex”. An arctic air mass reached well down into the southern parts of the country bringing the coldest temperatures and wind chills we’ve seen in nearly 20 years. Low Temperatures on Jan.4 in southern New Jersey fruit growing regions ranged from -6° F at Upper Deerfield to 2° F at South Harrison Township. In central and northern counties temperatures ranged from -5° F at Hackettstown to -12° F in Walpak. Some growers may be wondering how their orchards fared during the cold snap.

In general, our orchards went into the winter in good shape and there weren’t many severe temperature fluctuations until this cold snap, so hopefully not much damage occurred. A brief examination of orchards and vineyards in southern county cold spots revealed no obvious signs of southwest injury on fruit trees or vine die-back which were my main concerns. I do not expect much bud damage to tree fruit occurred although I intend to collect some twig samples and force them to see.

Extreme events like we’ve just experienced are why we generally recommend to delay pruning stone fruit for as long as is practicable. Although definitive research is lacking, anecdotal evidence suggests pruning may make fruit trees less hardy. Pruning pome fruit and native grapes should not be a problem at this time.  Pruning of vinefera varieties is best delayed until late winter or spring. Harold Larsen in Co. has a useful fact sheet explaining how to determine bud damage from freeze events. This will be handier as we get closer to spring of course.