I thought I would share my coldframe with you all. It is about to get LOTS of use. I built this coldframe about four years ago and use it primarily for hardening off seedlings. It works very well because the seedlings are sheltered from the high winds we get in the spring around here, and I can keep the rain off of the flats by closing the windows (when all windows are intact).
My sister in Maine would love a hotbed. A hotbed is basically the same as a coldframe but it has a source of heat, such as a heating cable run through the soil. I have also read that if you place a few inches of manure in the soil of a coldframe, the manure will decay and will also heat a coldframe. It has been my intent to try this method of hotbed gardening. But only for growing lettuce or other cool season crops, and here in Tennessee we probably don't need the added heat for them to grow well in a coldframe. Due to time constraints, I have not attempted growing anything in this coldframe in the soil, though it would surely work and I will try this year! Best intentions!
Coldframes like this are easy and inexpensive to build. I purchased the windows at a flea market or yard sale for a few bucks. Decided on the length I wanted my coldframe, keeping in mind the standard lengths pressure treated wood is sold in. I then measured the window width to ensure the length would work.
I used 2 x 10s for the back board and side boards, and a 2 x 8 for the front board. I wanted it slanted so as to maximize the sun's rays. My coldframe is oriented east, which works perfectly. It is a simple matter to shade the western sun when it gets too hot, as it often does in the spring around here. I assembled my box and cut the sides to accommodate the tilt; attached the windows with hinges and walah! Instant coldframe.
Over the years I have lost a few panes of glass as you can see. These two were taken out by an errant baseball and by an errant PVC part from the nearby PVC arbor. I have extra panes from some old windows so I just attach new glass with caulk and it is repaired. No big deal. The problem is cleaning up all the glass.
in the garden....