December Salad Days

This is a photo of our final garden harvest, taken on DECEMBER 14! We just finished eating the lettuce pictured above, on DECEMBER 27! And we live in WISCONSIN! How is this possible?
See below:

Here is a picture of our lettuce, taken just before our final harvest on December 14.

And here is the secret: our cold frame that protected the lettuce, even through temperatures around 0 degrees F. There was a lot of snow and cold between November 28 and December 14, and we were sure that the lettuce had died. But it hadn't! Cold frames really work, and they work in cold, snowy climates. We recommend them.