Our old cold frame fell apart over the winter so it came time on Easter Sunday to build a new one for the tomato and pepper seedlings we grow in our raised beds:
It so happens in the garage we have a couple of heavy glass doors from a curio cabinet. We only have the doors, not the cabinet. The doors measure 48 x 19 inches each. So first I found some old crap lumber around the yard to build a box to hold them:
The back plate is made from two chunks of high school bleacher seats with braces from a pressure treated 2 x 6. The sides are half inch plywood running from 13 1/2 inches at the back to 5 1/2 inches at the front. The front plate is the rest of the pressure treated 2 x 6. This is all old scrap lumber. Then I put the first door on:
Then I put on front plate with corner braces cut from a small junk piece of 2 x 4, and then attached the lower door. Except for the front plate, which needed 3 1/2 inch galvanized finishing nails, the rest of the cold frame uses 1 inch galvanized sheet metal screws left over from a metal roofing project.
So after a couple hours we have a 48 by 38 inch cold frame with extremely fancy doors for a cost of zero.
Queequeg T. Dog, Ph.D. inspects the finished cold frame with seeds installed inside, planted in cat food cans. Since we have five cats we have a never ending supply of empty cat food cans, which make ideal pots for starting tomato and pepper seeds. This will hold 150 seedlings. At night I put a dirty old sleeping bag over the frame to conserve heat. Total cost = zero.