New App Helps Fruit Growers Calculate Chill Hours

New App Helps Fruit Growers Calculate Chill Hours

The Mississippi State University Extension Service has launched Chill Hours, an app that helps growers assess growing conditions that affect plant physiology and prepare for the upcoming growing season.


Extension fruit crops specialist Eric Stafne and software architect Kelli Alexander developed the app to calculate the approximate number of chill hours. Many fruit plants require chilling to break dormancy and fruit normally in the spring. A chill hour is each hour the plant is exposed to temperatures below 45°F.

Growers enter their location by zip code or by clicking on a point on a state map and then enter desired start and end dates. App users can also access a precalculated chill hours calculator by tapping on a flag on one of 15 locations across the state. The app provides calculations of two different models. One is the common model typically used for blueberries, and the other is a more conservative model. Both can be used for any fruit crop.

The free app is accessible on iPhone and Android devices and at