2014 ASHS Annual Conference
19317:
Row Covers are a Weather Risk Management Tool in Plasticulture Strawberries
19317:
Row Covers are a Weather Risk Management Tool in Plasticulture Strawberries
Tuesday, July 29, 2014: 8:00 AM
Salon 11 (Rosen Plaza Hotel)
The 2014 winter season in the Mid-South proved to be one of the most challenging winters for management of cold weather
extremes since strawberry plasticulture was introduced in this region in the early 1980s. Though temperatures below -20 C
were not experienced this past winter (as occurred in January 1985), many strawberry growing areas in North Carolina
experienced temperatures of just below -17.7 C on 7-Jan-14. Despite plants bieng fully dormant at the time of this arctic
clipper in early January, significant crown injury occurred in both Chandler and Camarosa plants that did not have winter row
cover protection. The freeze-injured plantings were about 10 days later in crop ripening in spring 2014 than plantings that
had row cover protection. A second 'arctic clipper' occurred in the Mid-South over the period of 26-Feb-14 to 1-Mar-14, and
minimums were as low as -10 C in the NC piedmont. At this juncture, the crop had broken dormancy and was in the pre-
bloom period. With row cover protection during this second arctic clipper in late February, growers were able to save non-
emerged flower buds that were still inside crown, but a high percentage of newly emerged 'tight' buds were killed at -10 C.
Under the windborne freeze conditions of 26-27 Feb, a small number of growers attempted a relatively new technique of
using sprinkling in conjuction with row covers, and this approach proved to be very successful for saving all flower buds
stages (non-emerged and emerged) as well as the so called 'popcorn' stage (just before open blossom). The author will
describe a relatively new weather tool called the 'Row Cover Optimizer' that provides generally accurate two week weather
forecasts for strawberry growers in a 4-state region (VA-NC-SC-TN). With this tool, growers can better anticipate when their
row covers may need to be 'ON' for freezes, and they are also advised of mid-winter ‘warm up’ periods when covers need to
be 'OFF.' Whenever average daily temperatures in January are 4-5 C above normal, and this happens over a consective 2-3
day period, there is greater risk of the crop breaking dormancy underneath the covers. Smaller strawberry plasticulture
growers (< 4 ha) with access to family and/or local labor are generally more successful in making timely adjustments in winter
row cover usage according to changing weather conditions than are larger growers who depend on a migrant labor force that
is unavailable until early spring.
extremes since strawberry plasticulture was introduced in this region in the early 1980s. Though temperatures below -20 C
were not experienced this past winter (as occurred in January 1985), many strawberry growing areas in North Carolina
experienced temperatures of just below -17.7 C on 7-Jan-14. Despite plants bieng fully dormant at the time of this arctic
clipper in early January, significant crown injury occurred in both Chandler and Camarosa plants that did not have winter row
cover protection. The freeze-injured plantings were about 10 days later in crop ripening in spring 2014 than plantings that
had row cover protection. A second 'arctic clipper' occurred in the Mid-South over the period of 26-Feb-14 to 1-Mar-14, and
minimums were as low as -10 C in the NC piedmont. At this juncture, the crop had broken dormancy and was in the pre-
bloom period. With row cover protection during this second arctic clipper in late February, growers were able to save non-
emerged flower buds that were still inside crown, but a high percentage of newly emerged 'tight' buds were killed at -10 C.
Under the windborne freeze conditions of 26-27 Feb, a small number of growers attempted a relatively new technique of
using sprinkling in conjuction with row covers, and this approach proved to be very successful for saving all flower buds
stages (non-emerged and emerged) as well as the so called 'popcorn' stage (just before open blossom). The author will
describe a relatively new weather tool called the 'Row Cover Optimizer' that provides generally accurate two week weather
forecasts for strawberry growers in a 4-state region (VA-NC-SC-TN). With this tool, growers can better anticipate when their
row covers may need to be 'ON' for freezes, and they are also advised of mid-winter ‘warm up’ periods when covers need to
be 'OFF.' Whenever average daily temperatures in January are 4-5 C above normal, and this happens over a consective 2-3
day period, there is greater risk of the crop breaking dormancy underneath the covers. Smaller strawberry plasticulture
growers (< 4 ha) with access to family and/or local labor are generally more successful in making timely adjustments in winter
row cover usage according to changing weather conditions than are larger growers who depend on a migrant labor force that
is unavailable until early spring.