Growing degree units (GDUs) are a more effective measuring tool to predict crop and insect development throughout the growing season rather than simply relying on calendar days. Calculating growing degree units for corn uses a minimum daily temperature of 50°F and a maximum daily temperature of 86°F with a base temperature of 50°F.
((Max Daily Temp. + Min. Daily Temp.) / 2) – Base Temp. of 50°F for Corn = GDUs
Example: High 93°F Low 62°F
((86°F + 62°F) / 2) - 50°F = 24 GDUs
Example: High 78°F Low 48°F
((78°F + 50°F) / 2) - 50° = 14 GDUs
While monitoring GDUs can help evaluate crop progress, varying management and environmental conditions may affect the required GDUs of your specific crop, specifically during crop emergence early in the growing season. Factors such as residue carryover, soil texture, planting date, tillage practices, and seed depth may all increase the GDUs needed by 5 to 60 GDUs per factor.