Sympathy! I'll try to give a more direct answer in the next post, but this one may help ease the pain of "tables can only go so far" in producing firm answers. The number of variables in a garden is so large that local experience is better than "one size fits all" formulae.
Asking a neighbor or a Master Gardner or the local Ag Extension office would give you answers based on local experience. "Local" counts for a lot.
"Zone 8" can describe totally different climates.
"Average first frost date" says nothing about whether your fall is short and unsettled, long and cool, long and hot, dry, wet, loaded with insects ... etc.
But whether you start with the ATP sowing calendar, or research a dozen like it and average out the answers, you will still only get a first guess your first year.
I just read an post by Joseph in Cubits that he saved a LOAD of Bok Choy seed, and now he's going to start a few rows of Bok Choy every two weeks between now and whenever. That's one way to find the best date!
You can be EXTRA proud of any ripe crops you get your first year!
The ones planted too late, you might still be able to eat baby leaves if they are greens.
Or throw a low hoop tunnel over them and keep 'em alive into cold weather. At your latitude, daylength might not be a terrible factor, and they might still ripen at a time of year when normal farmers would look at you like a lunatic.
The ones planted too early will teach you what heat tolerance the varieties that you planted actually have in YOUR garden. You could shade them or mist them if you're stubborn enough to argue with the climate.
If you keep notes , your second year's guesses will be greatly improved. By the third year, you'll KNOW when ... except that you'll still be better off planting some 2-4 weeks early and some 2-4 weeks late, if you have enough room and enough seed.
Climate is what we expect, but weather is what we get.
