In my big city (Calgary) back yard I have a small greenhouse, unheated, and tucked in beside a garage, a fence, and some giant spruce trees from the property next door. Which means, its not very exposed and doesn’t receive full mid-day sunlight, ever.
I’m certainly not what I’d describe as a ‘seasoned gardener’ or even a particularly good one, but I try, and as I haven’t had many gardening mentors in my life, I tend to experiment. Over the years I’ve tried to develop a system which allows for 3 harvests a year; an early spring harvest of cold-hardy greens, starting late March and running through to the end of May, a summer harvest of tomatoes, cucumbers, basil, and other herbs, starting late May with a September harvest before the weather turns consistently cold, and a late-summer-into-fall crop of again, cold hardy greens, planted in August and harvested through November if the winter is mild.
Once the below zero temperatures begin, the late-fall crops in the greenhouse are draped with a single layer of floating row cover. On warm days I pull back the fabric to allow the sun to reach the plants. On cold or cloudy days, I leave it on. In the past I’ve never had any plants left to harvest after mid November, but this year I did, so kept the system going. In December we got our first real cold snap, with overnight temperatures reaching as low as -16 C. For over a week I didn’t go inside the greenhouse and imagined all the plants would have succumbed to the cold by the time I saw them again.
On December 11th I ventured inside and to my amazement, found several plants still thriving! They hadn’t grown per se, but the swiss chard, the collards, and the spinach had held their own under the row covers and were tender and delicious enough to eat raw.
Shortly after that, a serious cold snap lasting several weeks and temperatures as low as -40 C. settled in. I let all thoughts of greenhouse produce leave my mind. Until January, when a warm spell led me to think about the early Spring planting and the greenhouse clean up that would be needed.
To my utter amazement when I took off the row covers to assess the situation, I found that the spinach and collards had not only survived, they were vibrant enough to be eaten fresh! This find has led me to re-consider some accepted garden lore and excitedly further my experimentation. Next summer I’m planning for a big enough crop that with appropriate row-cover care, I can harvest all the way through to the Spring.
