We received a freeze warning in Vincennes last Sunday with a predicted low temperature of 33 °F. Growers in southern Indiana reported minimal damage on plants covered with floating row covers. But significant damage was observed in fields that were not protected or covered with a thin layer of floating row cover.
At Southwest Purdue Ag Center in Vincennes, the recorded low temperature at the strawberry plant canopy height was 26.5 °F. Open blooms and some pop-corn stage flowers were killed. Without protection, we saw varied damage among cultivars. The yield loss might be more than 70% on cultivars with the most open blooms. The early cultivars that have developed green berries suffered less yield loss as green berries can tolerate lower temperatures than open blooms. The very late cultivars that have not have flower clusters grown out of the crown survived the freeze event.
Lessons learned for the frost/free protection:
- Take action for frost protection whenever there is a frost/freeze risk, especially if strawberries enter full bloom.
- The actual temperatures at the canopy height could be lower than those recorded a few feet above the ground.
- Heavy row cover at least 1.5 oz/sq. yard should be used for frost protection.
- Planting a combination of early, middle, and late-season cultivars could reduce the risk