cold frame details

I had a couple of comments on our cold frame, and since it has worked so well for us I thought I'd put up some details.  We roughly based this on an old issue of Kitchen Gardener magazine, which we got at a used book store. It's from issue no. 29, October/November 2000.



The article was mostly about the lid, which is simply made from plastic (or even vinyl) sheeting stretched over the frame, held with staples and then secured with thin strips of wood.  We also liked the curved design, but it's probably not that necessary.  The article also has a cool snap-on cover design using PVC tubes, though since ours was fairly small and we had some old hinges laying around, we just used those.



Cold frames can be designed around a window you already have, or a space you want to put it.  We chose an interior size of 24 by 28 inches, so that it can hold four flats of plants.  Any bigger and it would be harder to move, but if you were making permanent beds you could of course go larger.



The angle of the top is also debatable, depending on where you live, etc.  Our design was based on materials--we used three 1x6's for the back, and two for the front, so just cut a board diagonally to make the angle. 

Originally we used an adjustable prop for opening the lid to different amounts based on the weather.  You do have to watch cold frames carefully as they can spike up to over 100 degrees rapidly in sunny weather.  Then I found a UNIVENT at a garage sale, and we installed that.  It works wonderfully, and now I'm not sure I could live without it!

This time of year, I find setting it on the picnic table is handy.  I move plants in and out of the house pretty often, so this is convenient for that.  It's basically an extension of my indoor light set up, and helps with hardening off since the plants are exposed to more heat and light, but protected from wind.    You could also use it on the ground, and surround it with hay bales etc. for more insulation.  I haven't tried it for overwintering yet, but might give it a shot this year.