Jeannette, I've been
getting lots of fall-gardening questions lately, so I thought I'd answer
yours in a post instead of via email. Persephone Days
are most relevant for people who garden in a mild climate, in a
greenhouse, or are growing hardy leaf crops like kale and lettuce. The
date tells you when these cut-and-come-again crops will stop producing
due to lack of sunlight, but it doesn't take into account killing
freezes that will completely wipe out your crops. Broccoli, for example,
is going to kick the bucket at 25 degrees Fahrenheit unless you cover
it well, so the Persephone Date (which comes much later than the
hard-freeze date for most of us) is irrelevant.
My favorite chart for fall planting is here, and I give you lots more information about how to choose planting dates and how to make easy frost-protection in my book Weekend Homesteader.
The short version is --- it's too late for you to plant carrots,
cabbages, and broccoli from seed, but you can still have a great fall
garden with leafy greens (kale is our special favorite) and lettuce,
which grow much faster than other fall vegetables. If you buy big sets,
you might also get away with planting out brussels sprouts, cabbage, and
broccoli now since you live further south than we do. We don't like
radishes, but I believe they're pretty fast so planting another round of
those as well as some turnips could fill in the gaps. Just be sure to
check the days-to-maturity date on your packets and add two weeks for
safety --- some varieties grow much faster than others!
I hope that helps, and
good luck with your fall garden. I always feel like I get more food for
my effort with the fall garden than at any other time of year, so it's
definitely worth figuring out.
These are my two favorite planting date resources. They aren't perfect as they don't take into account micro-climates and the weather you've been having recently (like if it's been an unusually hot summer, you might need to delay the planting a couple weeks past when they suggest), but they're a great jumping off point!
http://www.almanac.com/gardening/planting-dates/
http://awaytogarden.com/when-to-start-seeds-calculator/