Generally, vegetables that mature quickly and that are frost tolerant make for the best fall crops.
Vegetables that can survive light frosts (in the 30 to 32˚F range) include Beets, Chinese cabbage, cauliflower, celery, collards, green onions, potatoes, Bibb and leaf lettuce, mustard, parsnips, radishes, spinach, and Swiss chard. The flavor of some of these, such as collards and parsnips, is, in fact, much improved by exposure to a spell of below-freezing temperature.
Even hardier vegetables that can survive temperatures as low as 20˚F include cabbage, broccoli, Brussels sprouts, carrots, kale, leeks, rutabagas and turnips. Upon thawing out, these hardy vegetables will continue to grow between freezes!
Collard Greens seem easy to grow, so I sowed a bunch of seeds on 9/17/2020. They germinated on 9/22/2020. Looks like I will have Collard Greens for Christmas dinner!!!
10/13/2020 I love growing collard greens! They grow fast! I love it!