Today, I brushed the remaining 5" of snow off the cold frames that have been buried since January to see whether anything survived the winter.
We had picked spinach, mesclun, cilantro, and radishes into early January and then the snow covered the cold frames and we left them until today.
So, today I discovered that the spinach and arugula survived! However, a vole (or possibly a family of voles) kept themselves fat on the spinach the last two months. They didn't touch the arugula, but the spinach is all chomped and there is a rodent hole in the ground inside each frame.
The coldest temperature that I measured inside the frames before I removed the thermometer to use in the greenhouse was 17º. I don't know whether it got colder than that inside the frames in Jan/Feb. But they were well insulated by snow those two months, and there were clear signs of the snow melting at the bottom from the warmth of the ground inside the frames.
So, despite the absence of fresh spinach, I am declaring my winter experiment a success. We can grow greens through the winter.
Next winter we'll give them a warmer climate inside the greenhouse (The cold frames provide no warmth at all.). I've been sealing the drafts in the greenhouse gradually each weekend, and I've been able to raise the temperature inside at night from 9º warmer than outside temps to 20º warmer. Then, with low tunnels inside the GH, I've been getting another 10º boost for a total of 30º warmer than outside - using no artificial heat.
We managed to extend our season to 10 months this past year. Maybe we'll be able to extend to 12 months over the next year.
You don’t stop dancing because you’ve grown old. You grow old because you’ve stopped dancing. - apologies to G.B. Shaw
Keep us posted!
