One of the first things we did in late August 2017, just after we had moved in, was to sow some winter lettuce seeds and oriental mustards in the greenhouse. There are not many crops that can be sown in late summer, but these are an exception.
Just a few weeks later we had lots of baby salad leaves to eat which continued cropping through the winter. Although the plants grow much more slowly through the winter months they are sturdy plants that keep cropping.