Growing Degree Days have seemed to take on some popularity the last few years. A good thing. My father has hunted since 1948, and myself since 1972, in many states from Midwest to southeast. We have followed ground temps and air temps and growing degree days. Regarding growing degree days, our best collective hypothesis is morels generally begin fruiting between 800-1100 GDD. Yes, you will find an exception 5% of the time outside this range. The 3 main things that pull the morels within this range are 1) soil moisture, 2) duration and sequence of each cold, cool, warm and/or hot spell, 3) the January 1 starting point of soil temp & moisture.. The conclusion we have arrived at is once the first 1”-1.5” greys appear in a given area you have generally 250-350 GDD left for them to fruit; and it doesn’t matter if they started at 830 or 1075. Now, that will usually play out as 10 days on low end, 14 days on average and 18 days on the high end for the morels to fruit in that given area. Please weigh in if you follow or have interest in GDD’s