Last winter I reveled in the ability to harvest fresh greens throughout the winter using the heated cold frame my husband built for me. I even wrote an article ,”Cold Frame of Mind” in the November/December 2012 issue of Hobby Farm Home, describing how Grant put it together and how it worked for me during the winter. It was heated with a single 100 watt halogen lightbulb and worked fabulously well.
This year I was a little more burned out than normal by the end of the season after dealing with a terribly dry summer and a challenging situation in the community gardens. Basically, it was no fun and I was almost happy to see the season end. I didn’t do too much in the cold frame except to dump a few gallons of water on the existing rosemary, chard and the spinach that germinated in the fall. When we had a nasty snowstorm at the beginning of November I plugged in the cold frame since the temperatures were supposed to dip below zero degrees F. All was fine until the plugged pulled out of the socket. It went dark, and I figured the plants were done for the season. Imagine my surprise when they were fine. Even though it went below zero, there was snow on top of the cold frame, and everything came through without blemish.
We’ve had more inclement weather since then, but when the forecast called for temps of -13 degrees F. Grant wanted to use the extension cord for the heating cable on the beehives. It was a very difficult year for the bees so we want to do whatever we can to help them come through the winter in good condition. I thought for sure the cold, particularly since it didn’t have the snow cover, would end the cold frame garden. I took a peek again this weekend, and I’m shocked that it’s actually doing okay. The chard is a little wilty, but the rosemary and spinach look the same.
So what I’m going to do is just leave it. I want to see what the limitations are of this type of cold frame. It has insulated walls, and is buried in the ground, but other than that it’s just like any other cold frame. Maybe the insulation is enough to keep greens going throughout the winter. I want to find out. I know there will be plenty of cold weather to test the limits and see what I can grow without an addtional heat source. Let the experiment begin!

Amy, we’ve had good results with uninsulated cold frames here in Idaho. We can sometimes eat out of them until Thanksgiving or later (this year was later; serious snow held off until mid-December). Though once the many feet of snow settles in, we can’t get to them. (I think we will redesign them next year, so that we can get to them more easily during the depths of winter.) We were really surprised the first year in the spring. We had a romaine lettuce in there that was as fresh as could be! And some stray carrots–crispy sweet. Yum! I’m hoping for the best this year with the chard, kale, and sorrel I threw in there. I was having health issues and surgery going into the fall, and didn’t get as much done as I usually would have. Looking forward to hearing how your rosemary fares.
Wow, how great. It would be so nice to have fresh greens all year.
I’ve been impressed (and frankly surprised) this year, Rhonda. I especially like having the rosemary out there.
That’s amazing that your uninsulated cold frames hold onto things so long. I bet it was a treat to find the lettuce and carrots in there in the spring! I hope you’re feeling great, and ready for a fantastic year.