To improve on my timing for winter harvest crops, I’ve added a Winter Planting Calendar to my online planting calendar. I added a link on the sidebar and here too: Winter Planting Calendar.
I was reading on the Johnny’s Seeds website:
Winter harvest crops are planted in late summer or early fall for harvest throughout the winter. … for harvest before and during the “Persephone Period,” when day length is less than 10 hours and plant growth essentially reaches a standstill.
You can look up when daylight falls below 10 hours in your town using this site: USNO Duration of Daylight Calculator. For me, its November 10.
I’ve tried for many years to get a cold frame full of greens to eat all winter. One winter I was successful with a good crop of spinach. Usually I plant too late; the crop holds over the winter and begins to grow again in spring for a nice spring harvest. This is good too. Some winters, its just too cold and the crops are killed.
Using my new calendar I now know that its definitely too late to plant lettuce for winter harvesting. I have some seedlings I planted several weeks ago that should be good. But maybe I could get away with sowing some spinach and arugula seeds this weekend. I’m working on putting together a cold frame or some covered hoops in my garden.