The third challenge that most Idaho gardeners face is the very short growing season. At our high altitudes, it's not uncommon for winter to last into April and to begin again by October. Occasionally, we have killing frosts and snow as late as June and as early as September. The sooner seeds can get into the ground, the better, but that's a bit tricky when the ground is covered with snow.
If you've looked at my previous blog posts, you know that I'm fond of salvaging and recycling materials. The cold frame above was made from a salvaged window, salvaged "L" brackets, and scrap wood. It measures 56" x 24" and is 6 to 12 inches deep, which is a good depth for spinach and small lettuces. The frame faces South and is situated near my front porch. The ground there has been extremely inhospitable to nearly every kind of vegetation, so a cold frame seemed to be the best choice for the space.
The cold frame above was made from used brick, with a salvaged wood-framed window for a lid. The frame was lined with black plastic, and the seeds were covered lightly with soil and aged straw from the chicken coop. The spinach was planted in this cold frame in October, 2009, right before the first snow. This picture was taken in March, 2010, not long after the first plants made their appearance.
One of the things I like best about cold frames is that they may be made from nearly any salvaged material, and they are easy to assemble or to disassemble and move, as needed.