From my experience this past year, Rainbow Swiss Chard seems to be quite a versatile plant. It can take summer heat, as well as winter temps in zone 6a. I can’t think of many plants that can grow inside an unheated greenhouse in both summer and winter. In summer, temps in the greenhouse can reach well over 100 degrees Fahrenheit. In winter, I kept the plants inside a cold frame inside the greenhouse (2 layers of protection), so lets assume temps as low as 20 degrees Fahrenheit at times.
Pictured here are Rainbow Swiss Chard plants harvested from the greenhouse on January 20th, 2021. The only issue is we just don’t eat as much Swiss Chard as lettuces and other salad greens. In that case, I probably won’t grow as much Swiss Chard going forward and I’ll look for other vegetable plants that can withstand similar temperature extremes, which we do eat often. Any suggestions?
I decided to harvest entire plants, instead of the cut-and-come-again method, which works well with Swiss Chard, because the plants were being heavily invaded by aphids. Perhaps I’ll try the Neem oil to see if it is effective on the aphids on the few Chard plants that I did not harvest. Either way, it is time for a fresh start. I’ll probably sow Broadleaf Endive seeds (member of the Chicory family) in this cold frame shortly and they should come up beautifully by March.