Some gardeners grow vegetables year-round. I’ve thought about it, but haven’t tried it yet.
The article “Plant a Fall and Winter Garden” from suite101.com suggests looking at the days to maturity of vegetables to determine what you can grow where you live.
Carrots, parsnips, peas, beets, spinach, lettuce, onions, leeks, broccoli, collards, and cabbage are among the vegetables that are candidates for a winter garden.
However, if you’re planting seeds, the ground needs to be warm for them to germinate. That’s the first week in August in warmer climates.
Check with the Cooperative Extension Service in your area for information on what vegetables will work best for a winter garden in your area.
Update: This year I planted a winter garden. See my article "It's Time to Plant Your Winter Garden" for details.
Other resources for winter gardens are:
“Winter Gardening” – GardenGuides.com
“Winter Garden Versus Summer Garden” – Grow Better Veggies
“Plant a Winter Garden With These Simple Tips” – Mother Earth News
“Growing Your Own: Fall and Winter Gardening” – Oregon State University Extension Service
“Cool Season Vegetable Gardening” – About.com
“Best Producing Winter Vegetable Garden” – lovetoknow
“How to Plant a Fall and Winter Vegetable Garden” – eHow
“Winter Vegetable Gardening” – Organic Gardening
Tomorrow’s post on The Survive and Thrive Boomer Guide will discuss “How to Get Your Yard Ready for Winter.”