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 … [Read more...] about Grape phenology and GDD accumulation