How to Build a Cold Frame

Get an early start on spring planting or extend your gardening season with this DIY cold frame. A type of “mini-greenhouse,” a cold frame built with a glass or plastic lid allows plants access to sunlight and traps heat to prevent cold weather from putting an early end to your new crops. Follow these simple steps to construct your own cold frame using just a few tools, lumber, and a reclaimed window frame. The addition of a temperature-sensitive foundation vent will keep air flowing without risking plant loss due to unexpected cold snaps.