Chilling a fruit tree trains it against hard winter damage. During the warm months of the year, a young tree will develop buds that go dormant once the weather turns cold and the days are shorter. Once the buds have entered their dormancy period, says the Texas A&M Agrilife Extension, they will be able to tolerate lower temperatures. Trees that do not receive a good chill in their first year may be easily damaged by harder winters in following years. Chilling is a natural process that can not be forced, but observation will prevent your tree from being damaged.
Research the chilling requirements of your specific fruit tree variety to determine whether the winter in your area will provide a sufficient chill to prevent early fruit drop or poor fruit production before planting.
Determine the average hours of chill by looking at weather patterns in your area. An hour of chill is 60 minutes where the temperature is below 45 degrees Fahrenheit and above 32 degrees says Texas A&M Agrilife Extension. If you do not have sufficient weather records, contact your local extension service.
Observe your tree in the spring to determine whether it has had enough chilling time. Look for late or early bloom in the early spring, and crop loss in the late spring to determine whether the chill was exceeded for the year. Uneven blooming or delayed foliation indicate the chilling requirements were not met.