GDD base 50 accumulated since April 1 = 567 (Tuesday, May 26 - system down on Monday) http://agebb.missouri.edu/weather/reports/gddTable.asp Phenology stages according to the Modified E-L system http://door.uwex.edu/files/2010/10/ModifiedEichhornLorennzsystem.pdf … [Read more...] about Grape phenology and GDD accumulation