Winter gardening sounds like a daredevil sport. Frost nipping at your nose, icy winds trying to sabotage your seedlings, and yet, some plants thrive while you're bundled in three layers of clothing.

Gardening guru Eliot Coleman asserts that “the basic cold frame is the most dependable, least exploited aid for the four-season harvest.” We couldn’t agree more. Last winter, my humble box built of ...