Cold frame gardening is a great way to extend the growing season, particularly in more Northern climates like ours. Southern Ontario is a zone 5 hardiness, which means we usually can't really start growing until the May long weekend. The last expected frost date is May 16th. I expect the farmer's almanacs will be changing all this soon though, as climate change continues to wreck havoc.
Salad greens are the best to grow in a cold frame, because they are already cold-hardy. I know lots of people manage to grow greens practically all year round in hoop houses and other similar structures.
I chose to use bricks as the siding, because that's what I had lying around. There is a lot of debris and junk buried along the fence line in our backyard for who knows what reason, but I used this as an opportunity to clean up several little piles of bricks. Some of them are quite old and much prettier than the newer ones.
I laid the window sash on the ground and marked the outline with a garden edger (is that the right term?), then dug a little trench at a haphazard slope. The slope runs north to south, so that the tilted window frame faces south (this is important). Then I laid the bricks in, smushing them around and packing dirt around them until I had an approximately-level sloping frame. I set another row of bricks on top of that one, and filled the small leftover gaps with blocks of wood. Certainly not airtight, but I think that's okay. It's pretty makeshift, but I'm happy with that- I'm glad I was able to use all reclaimed materials to make this instead of buying new ones.
I planted the left half with spinach and the right half with buttercrunch lettuce, adding in a bag each of seed-starting soil and black earth. I simply scattered the seeds in, and I'll thin them once they start to grow. I want to try a few different planting techniques this year to see what works best. Scattering, row planting, starting seeds indoors, etc. I have no idea if any of this was done correctly or not, but it seemed good to me. Then the window was laid on top, a hole in the glass patched with 3mm plastic, and there you have it. Now I just water, and wait. Go figure it's a totally cloudy day today; hopefully it will clear up this afternoon.
I edged out an extended garden along the north side of the yard, here. Next step is to tear up the grass inside it and clean up the brush, then add in new topsoil. There are lots of perennials here (in the background), and I think I will concentrate on caring for them instead of planting anything new. Around the cold frame I think I'll plant some marigolds (a good pest deterrant) and some ground cover annuals like phlox or lobelia (I'm learning!)
Keeping that dog out of the garden is going to be a problem...