Plant Cover Crops
Crimson clover, Austrian winter peas, vetches, and grains such as wheat, oats, and triticale will boost the fertility and organic matter of your soil if you plant them now, let them grow all winter, and turn them under in spring. As an added bonus, winter cover crops host many beneficial insects.
Plug In Pansies
It's not too late to plant more pansies, and remember that blue goes with everything. Keep some pansies in pots, so you can shift them around wherever you want spots of color. Container-grown pansies often bloom earlier than those grown in beds, and they can last longer into fall and early winter since you can place them in protected areas when cold weather threatens.
Enjoy garden-fresh lettuce every chance you get. Harvest leaf lettuces first, because they're usually the least cold hardy. Romaine types stand up to winter cold best, followed closely by several types of butterheads. Still, plastic-covered tunnels are usually needed to keep lettuce protected and pretty through winter.
Arugula that grows in cool weather tastes great, especially young leaves taken from the plants' center. Use your fingers to pluck leaves that are about 6 inches long. After a quick rinse, you can cook them like spinach, chop them into salads, or layer them on sandwiches like watercress. Continue harvesting into winter since arugula is cold tolerant.
Transplant Sweet William
This fragrant old favorite grows best if you renew the planting each fall by digging rooted sections and moving them to new places in your garden. Any garden location that receives at least a half day of sun will be fine for sweet William. Plant some sweet Williams near peonies, which bloom at about the same time in spring.