>> Looks like Norfolk has an average of 4477 GDD. Shows how useful the USDA zones are on their own - we're in the same zone, but by this measure, I have more than twice as much heat as you.
I agree the USDA hardiness zones aren't good for much other than predicting best-case winter kills. (Even for that, I think the worst-case for killed-by-cold is very unpredictable, sudden, early Fall freezes and spring freezes after a long warm spell.)
I like to compare "Texas Zone 8" with "Seattle Zone 8". Texans are COMPLETING their spring tomato crop and complaining about the heat around the same time my nights are finally getting warm enough to PLANT OUT tomato seedlings in hope of ripening a few by late summer (isn't that when Texans start Fall tomato crops?)
So far this year Dallas, TX has had 967 GDDs, wheras an average year for them would only have had 496 by now.
My ZIP code has had 18 GDD by now. Average: 0.
Maybe, along with "av erage last frost date", we should be looking at "average date to accumulate 500 GDD".
I like "Sunset Climate Zones" enough to keep the link in my signature block (yours looks like 31 or 32), but no seed packet I've ever seen tries to give info for each Sunset Zone.
http://www.sunset.com/garden/c...
http://www.sunset.com/garden/c...
