GDD base 50 accumulation for April 9 = 0 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 It has been cold and NO GDDs have accumulated for this first week in April. … [Read more...] about Grape phenology and GDD accumulation