Our Concord is in full bloom (50%) and I saw some open flowers on Delaware, Valvin Muscat, Sunbelt and Catawba. So begins grape flowering – we keep our fingers crossed for nice warm and dry weather for good pollination.
GDD base 50 accumulated since April 1 = 544
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