The best time to plant for fall and winter eating may have just passed, but if you haven't been able to do it yet I'd suggest going out there right now and sowing some lettuce, arugula, spinach and corn salad, especially if you have room in the greenhouse or a cold frame or any other place you could shelter after the weather turns. It is probably not too late to plant cilantro, which is surprisingly hardy-- one Lasqueti gardener had hers survive outside last winter, with no protection, through all that snow and cold. If you can get transplants from a neighbour, or find plants for kale, Asian greens, or lettuce at a nursery, that would put you a couple of weeks ahead of direct seeding.
Through early October you can sow lettuce, spinach, arugula, and Asian greens, under a cold frame or in a greenhouse, that will germinate and stay small through the winter and begin to grow quickly when the days lengthen in February, giving you salads in the early spring, before you need the greenhouse for tomatoes etc. Whatever you do, be sure to get cover crops on the bare patches in the garden as they appear after harvest. If you are able to do only one thing for your next year's garden, this is the best. Make a note of the fall and winter crops you wish you'd gotten seed for this year, for next year's seed ordering. The whole schedule of what to plant when is on the main page of the Zero Mile Diet site.