Overwintering hardy crops in the vegetable garden is a valuable season extender.
Just like ornamental plants, crop plants can sometimes grow slowly or go dormant in the cold without dying off. Some veggies grow best in cool weather. One needs to grow them in the cool of spring, fall and sometimes even winter, in temperate areas to get a good result. These crops include things like spinach, lettuce, radishes, fava beans, garlic, broccoli, and Brussels sprouts. It is also commonly held that some of these crops sweeten with the cold, that their starches convert to sugars.
So, I’m talking about 2...wait, 3 things here…
One, planting in the fall, so growth can proceed right through winter and/or go dormant and then start up again with no further effort in spring. Some breeding programs are selecting for open pollinated arugula, collard and tatsoi that are especially cold tolerant. I've read plants don't take up nutrients directly from the soil well when the soil is less than 50 degrees F. and so these teeny newbies may benefit from a spring tonic of a very dilute liquid fertilizer.
I’ve long read that spinach can be planted in the fall for a very early spring harvest and have succeeded in doing so this year.
Fava beans (also known as broad beans), a member of the vetch family are sometimes planted in fall for an early spring crop. By my reading this is more a British tradition than American. There are certain varieties more suited for fall plantings. I have not yet done this myself.
It seems to be common knowledge that garlic should be planted in the fall to be harvested the following year.
Two, allowing the mature plant to remain in the garden as a means of winter storage rather than harvesting. I’ve read of this with carrots and parsnips.
Three, Winter Sowing, which I noded some time ago but have yet to actually do.
Ice-bred Arugula, Champion Collards, and a similarly developed variety of Land Race Tatsoi are sold by Fedco Seeds at http://www.fedcoseeds.com/index.htm
For the quest...
FloraQuest 2011: If We Cantelope, Lettuce Marry!