[I was reminded of this old article of mine after seeing John Robb's recent post about cold frames. I'm sure there are better DIY instructions out there, but some people found this helpful and maybe a repost will be useful to some more. (EDIT: Added comments at the bottom about angles and sourcing materials that I also posted on Robb's G+ article about this.)
This was an article I wrote several years ago for Green Options, and was probably one of my most popular pieces. (GO eventually turned into a number of different blogs, including Green Building Elements, where I wrote for a couple years, and you can find the original there.) It's a longish piece, as well, since it's DIY instructions, so I'm tucking it behind a cut. The links didn't copy over (and are probably out of date, for the most part), but I'm tracking down a couple of the images and adding them back in. I had a nice hand-drawn diagram illustrating the construction, and I need to see if I still have a copy of that somewhere that I can add in here to help make this more useful.]
Weekly DIY: Cold Frame
This weekend we got the first tantalizing taste of spring as the weather was clear and bright and temperatures rose well above freezing for the first time in months. Snow melted (though not entirely yet), and started the thoughts of summer gardens in mind. But nighttime temperatures are still falling below freezing, and it’s far too early to put plants in the ground, unless you provide a little assistance.
If your garden has a spot with good access to the sun throughout the day, you can use a cold frame to start your plants earlier in the year than you would otherwise. A cold frame is a very simple item. It is really just a small greenhouse. Daytime sun will warm the air and the ground inside, making it easier for plants to start growing. Nighttime temperatures inside the cold frame may fall back close to outdoor ambient temperature, but the extra heat gained during the day and the wind protection the enclosure provides will help keep the plants alive even if there is an overnight frost.
Building a cold frame should be a simple project. An elaborate structure is not required. It should cost little or nothing to build and nothing to operate. Plants can be started close together while they are small, and then, as they get bigger and the weather gets nicer, they can be moved out of the frame and put into the garden. (more…)