Many fruit trees need winter’s cold in order to flower and fruit well in the growing season. New York State is known for its excellent apples, a fruit tree with a particularly high chilling requirement. Pears, cherries, peaches, plums, apricots, and other fruit trees must also experience a minimum number of chilling hours over the winter to produce good fruit. In the South, many fruit trees will not produce at all unless special low-chill varieties are planted, because winter temperatures do not stay cold long enough. Here in the Catskills, gardeners are fortunate to have the right number of chilling hours for a wide range of fruit trees.
Chilling hours are the number of hours between fall and spring when temperatures remain between 32° and 45° F. Orchardists have long understood that fruit trees require winter chill, but neither growers nor scientists have yet identified the exact biological mechanism that links chilling to the development of healthy flowers and fruit. What is clear is the effect of insufficient chill: trees that receive too few chilling hours tend to flower late, with poorly formed blossoms. If they produce fruit at all, it is often small, misshapen, and more vulnerable to pests and disease.
Apples typically require more chilling hours than most other fruit trees, and some of the tastiest varieties have especially high requirements. Empire and Liberty apples need at least 800 chilling hours; McIntosh requires about 900; Honeycrisp needs around 1,000; and Red Delicious generally requires between 1,000 and 1,500 hours to produce well. In the Catskills, we reliably experience enough winter chill to grow even these demanding varieties. Paradoxically, some areas farther north are actually too cold to accumulate sufficient chilling hours, because temperatures drop below freezing too quickly in the fall rather than lingering in the critical 32°–45° F range.
Last winter, from fall 2024 through spring 2025, chilling hours in our region ranged from a low of 1,717 in Tannersville to a high of 1,814 in Shandaken. It was a relatively warm winter, with fewer chilling hours than in some recent years—for example, Shandaken recorded 2,259 chilling hours in 2024. As climate change continues, many areas of the United States where fruit trees once thrived may begin to experience too few chilling hours to sustain reliable harvests. The Catskills, however, retain some margin for warming: even fruit trees with high chill requirements, in the 1,000–1,500 hour range, should continue to perform well unless winter temperatures rise dramatically.
Other fruit trees have lower chilling requirements. Among European pears, Bosc requires 800–900 hours, Anjou 700–800, and Seckel 500–800. Asian pears generally need about 450–500 chilling hours. Bing and Royal Anne cherries, typical sweet cherry varieties, require 700–800 hours. Among plums, Italian Prune and Stanley have relatively high requirements of 800–900 hours, while varieties such as Satsuma plums can grow much farther south, needing as few as 300 chilling hours.
Peaches are often associated with warm climates, where they produce their sweetest and most flavorful fruit. Still, some varieties perform exceptionally well in cooler regions. One of the best is Contender, which has an unusually high chilling requirement for a peach—at least 1,050 hours. As the climate warms, our region may land in a sweet spot for this variety, offering sufficient winter chill alongside hot summer days that help the fruit reach peak flavor.
Persimmon trees, among the most cold-hardy fruit trees, ironically have very low chilling requirements, typically between 200 and 400 hours. Our native American persimmon is especially hardy, with some trees known to have survived temperatures as low as minus 20° to 25° F. Smaller and often more flavorful than the better-known Asian persimmons, American persimmons require both male and female trees to produce fruit. Otherwise, they are among the easiest and most reliable fruit trees to grow, having evolved alongside native insects and, so far, remaining largely unaffected by invasive pests such as spongy moths and spotted lanternflies.
Most European and Asian fruit trees are not gender-specific, but many still require cross-pollination. Typically, a tree needs a nearby tree of a different variety of the same species that blooms at the same time. For example, a McIntosh apple tree must be pollinated by a non-McIntosh apple with overlapping bloom periods. Most nurseries provide charts showing compatible varieties, making it easier for gardeners to choose trees that will successfully pollinate one another.
Margaret Tomlinson is a contributing writer. You can send her an email at reporting@theoverlooknews.com.