GDD base 50 = 84. We track GDD at  http://agebb.missouri.edu/weather/reports/gddTable.asp and rate the phenology stages according to the Modified E-L System http://door.uwex.edu/files/2010/10/ModifiedEichhornLorennzsystem.pdf A critical freeze is predicted for Tuesday night, so we will see how things look afterward!! … [Read more...] about Grape phenology and GDD accumulation