Penn State University Releases Update On Cold Hardiness of Fruit Trees
January 20, 2016 In the latest Extension bulletin, Rich Marini, Department of Horticulture Head and James Schupp, Professor of Pomology, give growers an in-depth look at how trees respond during dormancy.
“Most varieties of apples take over 1,200 chill hours. Mixing periods of chilling with periods when temperatures are warm seems to lengthen the chilling requirement,” they write. “This probably explains in part why we can call these trees well-adapted to our fluctuating winter weather.”
Schupp and Marini also say pruning trees in late fall and early winter will make them more susceptible to cold injury.
“It is best to wait until the trees have been exposed to freezing temperatures and until the leaves have begun to turn yellow before beginning early dormant pruning,” they write. “Keep a watchful eye on the long-range forecast and suspend pruning when a severe drop in temperature is forecast. Recently pruned trees can be damaged when temperatures suddenly drop 50°F to 60°F degrees to 0°F or below. This increased sensitivity is greatest within 48 hours after pruning and gradually declines over a two-week period.”
New Tree Fruit Production Guide
Penn State University Extension also recently released an updated production guide which covers orchard nutrition, spraying, pesticides, storage of tree fruit, farm markets, marketing, weed control, insect control, diseases, and more.
Subscribe Today For
