Each week we will be offering the air Growing Degree Days (GDDs) for corn that have accumulated to date from 13 locations across the team 8 county area.  A thank you to our intern Peter Burritt for pulling this information together.

Four planting dates will be listed and included will be:

 GDDs Season To Date
15 Year Average GDDs
30 Year "Normal" GDD
Period of Record - Max and min recorded GDDs for that time period

See: Growing Degree Day Calculator

Growing Degree Days for corn are Base 86/50 degree F and calculated by taking the average daily temperature, ((Daily Max Temp - Daily Min Temp)/2) - 50.  But the maximum temperature cannot be more than  86 degree F and the minimum less than 50 degree F.

 With the exception of the May 1 planting date GDDs are at or above the 15 year average and definitely above the 30 year "normal" for the date and the May 10 and 20 planting dates are near record GDDs for this date.

Some tassels have already been seen this week as more earlier planted corn at lower elevations should begin tasseling/silking (1200-1300GDDs) in the next week.  Take note of tasseling dates as Joe Lawrence from the ProDairy Program indicates silage harvest is likely to begin about 800 GDDs for 101-110 day hybrids and 750 GDDs for 96-100 day hybrids after tasseling:

Record Silking/Tasseling Dates for Corn Fields

Some of the greatest corn yield losses can occur from drought stress at tasseling/silking.  As of July 14, all eight of our counties were listed in the abnormally dry category at the United States Drought Monitor site and much of Saratoga County indicated as moderate drought:

NY State Drought Monitor Map

See the attached table for more of the July 17, 2020 results.
See the attached pdf for a good guide on corn development and our reference for growth stages.