An Introduction to Cold Frames

 

15 degrees out and four inches of snow on the ground!

15 degrees out and four inches of snow on the ground!

It’s the dead of winter, but it’s a sunny day. If you park your car in the sun, it’ll be warm inside – even though it’s freezing outside.

What if you could grow plants in there? They’d have warmth, shelter from snow and wind. They’d keep their moisture and not dry out.

With a cold frame, you can do exactly that. A cold frame is a wooden box that you put on top of soil, about a foot high. It’s got plastic or glass panes on the top to let the light in. Here’s mine in the dead of winter:

But inside, life continues, buoyant....

Inside, life continues, buoyant….

Inside, high humidity and above-freezing temperatures.

Inside, high humidity and above-freezing temperatures.

This winter, I grew Mâche (corn salad), Minutinia, Claytonia, Arugula and Mizuna to pretty good success. Now that spring is coming, I’ve sown in French Breakfast radishes. A cold frame can extend a growing season from fall into winter; it can grow plants through a freezing winter; and it can give you a head start on spring growth. In Cincinnati, our last frost-free date is about May 8, but I had sown my radishes on March 20th. I should get a harvest by the beginning of May, before plants can even be safely put out unprotected.

I love my cold frame and I’m going to be writing a lot about it. If you want to know more about them, ask here! I also suggest picking up the book Four Season Harvest by Eliot Coleman. I read his book years ago and it gave me the idea to finally build one this year. His text is a phenomenal starting base for how to get into cold frame gardening, which is mostly about working with the weather instead of against it.

Setting up a cold frame is a bit of an investment, but it’s a great way to perpetuate the wonderful hobby of gardening through the winter. In future posts, I’ll explain the construction of my cold frame and how to get the most out of them.