GDD base 50 accumulation since April 1 = 3647. 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 All grapes have been harvested and leaves are beginning to fall. We are going through marking low pruning weight vines and also marking layers. … [Read more...] about Grape phenology and GDD accumulation