In many Northern climates, you can still grow crops for fresh eating in the colder months! Here in Philadelphia, and even as far north as New England, with proper protection (high tunnels, low tunnels, or row cover) we can sow winter-hardy annual greens (like those shown here) in November for harvest as early as late February through March. These same crops can be sown in August or September for fall harvest. Perennial crops like Skirret and Good King Henry can be sown in spring and harvested the following winter or early spring.
Please read the "Planting Notes" on each page for best times and practices for sowing your cool season crops.