Fall Gardens are pretty short lived, so you have to choose seeds that have a quick growing cycle. Otherwise, you can buy plants at the garden center to have bounty before frost.
My favorite publication site is:
Just enter “Fall Garden” in the search bar and all sorts of relevant information will pop up. Great site with great resources!
Here are the seeds I plant for Fall: turnip greens, kale, collard greens, lettuce, spinach, radishes, mustard greens and carrots.
I plant them in a raised bed that we convert to Cold Frame (made with recycled old windows to let the sun in) when the weather starts to get cold and frosty. I will share more about Cold Frames another blog.