Too cold for apple buds?

Asked May 5, 2020, 7:09 PM EDT

Hello - we have a couple of apple trees that are in bud, and there are low temperatures forecast just above freezing. What, if anything, can we do to protect the trees? I believe they are Honey Gold and ... I can't remember the other. Tags are at home. The trees are about 5 years old. Thanks!

Hennepin County Minnesota

1 Response

Physical bud death from cold temperatures occurs at different temperatures depending on the development of the plant. Lower temperatures will kill more of the buds than warmer temperatures. For instance, after 30 minutes at 15 degrees Fahrenheit, 10 percent of the silver tipped buds, which is the first stage after dormancy, will die, but when the temperature drops to 2 degrees F, 90 percent of silver tip buds die. The lowest temperatures the buds can stand increase as the buds grow to have green tips, show 1/2 inch of green and have tight clusters. By the time the buds have pink tips and begin to bloom, temperatures below 28 degrees F will kill 10 percent of the buds on the tree, and lows of 24 to 25 degrees F will kill 90 percent of the buds.

Here is NOAA forecast although there will be some minor variances. https://www.nws.noaa.gov/wtf/MapClick.php?lat=44.95&lon=-93.28&lg=ep