GDD base 50 accumulated since April 1 = 434 (+61 departure from normal) at Mountain Grove 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 Observed open flowers on Concord, Sunbelt, Catawba, and Cayuga White. … [Read more...] about Grape phenology and GDD accumulation