University of Florida

What are Chilling Hours?

In order to bloom in spring, deciduous fruit trees like peaches, plums, and nectarines all must go through the plant equivalent of a long winter’s nap.

They need a dormancy period with a certain number of chilling hours, when the temperature drops below 45 degrees Fahrenheit.

The exact number of chilling hours depends on the fruit tree variety, but it can be anywhere from a hundred to more than a thousand.

Here in Florida, gardeners should look for special “low chill” fruit tree varieties.

Low-chill peaches, plums, and nectarines need just 100 to 525 chilling hours per year, making them better suited for our mild winters. Low-chill apples are also available, though there are fewer varieties that work well in Florida.

UF/IFAS Publications

Also on Gardening in a Minute

Other Sites

Chilling hours map for Florida
Click to see larger image

Vegetable Gardening
Missed a Show?

Here are two easy ways to catch up: Archives and Podcasts