At long last... a standard cold frame! I've always wanted to build one.
My first traditional cold frame started off with some very thick, gorgeous (but on their way to rotting) boards from behind our shop. My dimensions were based on the size of a window my Dad gave me.
After building the base frame, I set about making the sloped sides. I'd never used triangular pieces for creating slope before, and it took a few tries with the chalk line to get it right. A chalk line is a great way to experiment visually without making any permanent errors. I found that I wanted a flat top on the triangle, to align with the rest of the frame, so I made allowance for that and just made sure the bottom of each triangle matched the length of the frame. This is a spruce plank that my husband milled.
Here is the sloped frame resting on the base frame... ready to tackle fitting the window.
Perhaps the most important concept I've found when building a sloped cold frame is that a solid roof on the North portion will not block sunlight. This may seem contrary to what you'd imagine. However, I've tested it out with the underground cold frame and it's definitely true, particularly during the months when the sun is lower in the sky (which is when you most need the cold frame). Most of your sunlight will be at the north end. This means you should really consider expanding your well-lit real estate inside the cold frame by making the frame longer than the window.
If you look closely here you'll see that the solid portion of the top is not blocking any light. Only the front and sides are.
I am super lucky that my Dad fitted this window with hinges before giving it to me. What a lovely surprise! Thanks, Dad!
Here is the cold frame in its new garden home, on top of the Horizontal Spruce Central bed. Hopefully this structure can capture some of the heat that is probably rising from the decomposing hugelkultur below.
I added a pivoting arm to hold the lid open as needed. It consists of an edge from slab wood held to the base frame with a nail that is pounded only partway in.
I'm really happy with how this cold frame turned out. Although there are still some clods of frozen soil, this bed was covered and had thawed out enough to plant! February 28th and I planted carrots, onions, and radishes. I had forgotten the radish seeds earlier, so I walked down to the garden after dinner and planted them in the moonlight, with Venus and Mars above me to the west. We'll see what happens next inside this frame... The weather has been unseasonably mild, so I might as well take advantage of it. This cold frame helps me do just that. Plus, it will keep marmots out, once they wake up!
I'm feeling ready for spring.