Well, we woke up to snow yet again this morning in Garrett County. Will spring ever arrive in Mountain Maryland? As we ponder that question, I thought I would share a trick that keeps a bit of green from our garden on our family’s table year round. About fifteen years ago, we ordered a cold frame from a company in Vermont. It was made in Austria, and the box that it was shipped in had pictures of cabbages growing happily inside the cold frame. I decided that I would skip the cabbages and try growing perennial herbs in it.
After lots of trial and error, I’ve found that I can harvest rosemary throughout the year (the picture is from this morning). The cold frame also prolongs the growing season for sage, bay laurel, and oregano through early December and then protects those plants as they overwinter. Chives magically reappear in the cold frame each year in the late spring, but I haven’t had any luck overwintering tarragon. Likewise, thyme has never thrived in the cold frame—it does better in a pot on the patio from late spring through the early fall and then I bring it in during the colder months to live as a snowbird houseplant.
Some technical details about the cold frame: it has twin-wall polycarbonate panels in a metal frame with four hinged windows on top that open as needed using solar-powered hinges. The windows can be removed entirely in the warm months.