Kate Jerome, of www.garden.org, says you can grow greens all year round by making a crude greenhouse. She recommends using woodchips to a depth of 6″, covered with 6″ of compost (worm castings are best). Lettuce, chard and any variety of greens can be grown in this medium, and as fall approaches, you can cover it with hoops of pvc pipe covered with plastic sheeting. This should extend your growing season through the winter!
Some of the greens in our community gardens have come back from last fall, specifically mustard greens and kale. Should we pull these? They go to seed quickly. Can we save the seeds? We have some great gardens started already this year. In my plot we are already harvesting the early radishes and green onions. We are meeting some great people and the gardens look to be a great success again.