Midwinter temperatures of 0°F may kill some fruit buds on peaches. Many buds may be damaged if the temperature drops below -10°F. However what is most important is the temperature which occured within several days before the drop. If temperatures were already cold up to the low temperature drop, much less bud injury and death will occur. Buds and flowers will survive slightly lower temperatures if the drop is very slow, and if the minimum temperature occurrs for only a short period. As the buds swell and develop in early spring they become less cold hardy and prone to injury. Unopened peach buds showing pink color will survive temperatures of 20 to 23°F. At full bloom, damage can occur at 29°F. Ten days after bloom the young developing fruit will withstand only 28°F.

To determine the extent of injury after a cold snap, take shoots cuttings and place in water; the buds will open and bloom. Check to see if the center of the flower (pistil) is brown. If brown, the blossom is damaged and will not bear fruit. Only 7 to 10 percent of the total flowers on a fruit tree are needed to produce a good crop.

Consumer Horticulture | Quick Reference

© Erv Evans, Consumer Horticulturalist
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