Here is the first phenology observation for 2018! GDD base 50 accumulation for April 1 = 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 … [Read more...] about Grape phenology and GDD accumulation