Fall 2022 Strawberry Planting Advisory: Part 4
Temperatures below 10°F can result in injury to strawberry crowns.
The forecast is calling for temperatures in the teens to single digits on December 22nd.
Strawberry growers should cover their crops early next week (Dec 19th-21st).
A 1oz row cover can keep the crop about 3-6°F warmer than the outside air. A 1.5 oz will provide additional protection. A double layer of row cover does not double heat retention/protection provided by the row cover, and generally the 2nd cover only adds 1-3 extra degrees. So this means applying 2 layers of 1oz row covers could potentially insulate the crop 4-9°F above the outside air temperature. Double row covers may be worthwhile in some locations. Windy conditions reduce the ability of row covers to retain heat. Snow on top of the row cover provides lots of extra insulation, and ideally, we may get some snow on top of the covers during this event in some places.
A few comments and observations:
Late Planting: Many strawberry crops were planted late and then have been under the row cover since November. In some cases these plantings do not have the appearance of a crop that has started to go dormant. These crops will be more prone to cold injury potentially at temperatures above 10°F.
Previous Cold injury: There was concern about potential for cold injury from the early freezes in Oct and Nov of this year. We have sampled strawberry crowns at several locations, and we have found some minor cold injury (rating of 1 in pictures below) present in some locations and on some cultivars, however the damage is not widespread or very severe. Low levels of cold injury (Rating 1or less) will have minimal impact on crop production. Now is the time to protect the crop from any further injury that may have a more drastic impact on crop production.