Managing Winter Injury for Annual Strawberry Plasticulture Production Systems in the Great Plains

Local production of strawberries in the Great Plains is limited due to poor performance of traditional perennial production systems. Growing strawberries using annual plasticulture production systems has been widely adopted in the Southeastern United States. However, one barrier to successful adoption of this system in Kansas is the proper recommendations for application timing and thickness of row cover to reduce winter injury. The goal of this work is to determine optimum row cover management strategies to reduce winter damage and subsequently increase yield in annual strawberry production systems. Trials were conducted from the 2011-12 to the 2013-14 growing seasons at Wohletz Farm Fresh. A second on-farm trial location, Gieringer’s Orchard, was added for the 2013-14 season. The trials were located within production acreage and were treated identical to the rest of the field. A randomized complete block design was utilized with four replications. Typically, row covers are applied after 30 days/nights with <30^oF temperatures. In this study, we applied row covers after 25 and 35 days to determine how timing affects crop yield. We also utilized two thicknesses of row cover (1.0 oz/yd and 1.2 oz/yd) comprising a total of four treatments. In the 2013-14 trials, an additional row cover treatment (1.5 oz/yd) was implemented at both locations. Yield data from the two growing seasons (2011-2013) showed inconsistent results, probably due to the contrasting environmental conditions. 2011-12 was a particularly mild growing season. During the mild winter, the 1.0 oz/yd fabric had higher yield, although results were not statistically significant. In 2012, the 1.2 oz/yd fabric performed better and had higher early yield. Our data showed that row cover timing had little effect on berry yield, but applying earlier (25 d) was advantageous during the colder winter (2012-13). Microclimate data showed that soil temperatures were highly affected by row cover application timing. Applying the row cover had immediate effects at maintaining soil temperatures and higher temperatures were seen among the 25 day treatments regardless of the row cover thickness. Interestingly, it took approximately 14 days for soil temperatures to become similar after row cover was applied to the late treatment. Both row cover types provided excellent protection to the crop during <10^oF temperatures and minimum temperatures under the covers were never less than 25^oF. Our results suggest that growers in the Great Plains should use thicker row covers and apply them earlier compared to recommendations for the Southeastern United States.