What is GDD?

The Growing Degree Day, GDD, (also referred to as Growing Degree Units, GDUs, or Heat Units) is a heat index that can be used to predict when a crop will reach maturity. Each day’s GDD is calculated by subtracting a reference temperature, which varies with plant species, from the daily mean temperature.
Unless plants are overly stressed by drought or pests, the total GDDs accumulated throughout the season can be used to predict when a crop will reach maturity. Corn, for example, requires 1360 GDD to mature.

What data is presented in the GDD counter?

Manna’s GDD counter presents the current accumulated GDD of a specific field, based on temperature observations and default thresholds which were selected for each crop by Manna’s agronomy department. The counter is displayed for selected crops and will be added to additional crops in the future.

What else should I know?

  • The GDD accumulation starts on the Season Start date (as set in the field setup form or in the Edit Growth Stages function).
  • The GDD counter is not displayed to fields which are Out of Season.
  • The counter presents the accumulated GDD until today in either degrees Celsius or degrees Fahrenheit, according to the Units selected by the user through the system’s profile settings.