Alternating warm and cold weather in the spring can lead to frost damage to strawberry blooms. A temperature of 30°F at plant level can cause some damage; a temperature of 28°F will cause considerable damage to flowers. Injury is worse if the low temperature lasts for several hours and the wind is blowing. Unopened buds are more hardy than open blooms. The petals may still be white, but if the center of the bloom has turned brown, it will not produce fruit (Figure 12-4). Some protection from frost can be obtained by covering plants with 2 to 3 inches of straw, old cloth, paper, or row covers. Sheets of plastic give little or no protection.

Commercial growers protect their crop by running the irrigation system continuously during freezing weather. As water freezes, heat is released by the freezing process. As long as an adequate layer of freezing water covers the buds or berries, the temperature will remain at or near 32°F. If the irrigation is interrupted, turned off before all the ice melts, or is insufficiently applied, the irrigated blooms will suffer more damage then if they had not been irrigated. If the icy coating is milky white, not enough water is being applied; the ice should be clear. Unless you can guarantee that water will be continuously applied until the ice melts, this method should not be attempted. Windy conditions make the constant, uniform, application of water difficult or impossible.

Consumer Horticulture | Weather

© Erv Evans, Consumer Horticulturalist
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