Last year was the first time I grew vegetable in a cold frame. It was an experiment in extending the growing season without using a heater. I started late in autumn so the seedlings didn’t have much of a chance to build up strength. The winter was also brutally cold with temperatures dropping below 0ºF for several days at a time. Two feet of snow completely blocked the path to the cold frame and turned it into an isolated igloo-like structure.
I didn’t expect anything to survive in there. The weekend before last when it rose above 40ºF, I decided to open the plastic cover for the first time. To my surprise, some red leaf lettuce, kale and broccoli raab I had sown last fall survived. The parsley I transplanted there also survived. The cold frame actually works. If I had started it early in the fall and had access to it I would have had a better outcome. I still have more to learn as well as adjustments to this system.
Almost three months of no watering and most of the soil was still damp though parts of the top layer had dried up in places. The plastic cover is not just to keep the cold air out but also to keep the heat and moisture in. After opening it, I kept the plastic cover open on both ends to allow fresh air to flow through and for me to be able to water the soil inside. Then I sowed Pac choi, Arugula, Chinese celery and Mizuna inside. The Pac choi sprouted first, six days later.
I opened the cover again this weekend and kept it open for most of the day as it wasn’t very windy and the temperature stayed above 40ºF. I also put in spinach, French radish and Cherry belle radish seeds. If everything works right in the cold frame, I won’t have to wait much longer for my first backyard salad.