With the first blasts of arctic air from Canada comes the cold, hard truth that winter is right around the corner. While gardeners in warmer climes (USDA zones 8 to 10) relish the cool air because it signals fall planting time, most gardeners across the country know it's time to wrap up the garden. There are plenty of fall chores to do, such as protecting annual crops from frost, putting perennial gardens to bed for winter, and preparing trees and shrubs for the cold. By spending a little time this fall sprucing up the lawn or weeding the perennial garden, you can insure a healthier start to next year's garden season. Here's a checklist of fall activities to get your gardens ready for winter.
The first frost isn't necessarily the end of the harvest season. If you're growing cool-season crops, such as lettuce and broccoli, or trying to tease the last few vegetables from warm-season crops like tomatoes, you can protect them to extend the harvest window. Drape cloth sheets or tarps over the plants, making sure they touch the ground to hold in the heat around the base of the plants. Shield choice plants with plastic buckets when frost threatens, then remove them the next morning. There also are a number of effective products that can protect plants into autumn and even early winter.
* Floating Row Cover. Made from lightweight, spunbonded polyester or spunbonded polypropylene fabric, floating row covers are loosely laid over plants and anchored down with soil, stones, or sticks. They allow the sun, rain, and air to reach plants, yet protect crops when temperatures drop into the high 20° F. They come in different thicknesses; the thinnest ones won't protect against frost, but the heavier ones can protect plants down to about 28° F.
* Grow Tunnel. Grow tunnels are made from row cover fabric stretched over a metal or plastic frame. Some grow tunnels have slits allowing for natural venting so plants don't overheat, but these don't offer much protection against the cold. The thickest grow tunnel fabrics protect plants down to about 26' F.
* Cloche. Shaped like a bell or dome, cloches are usually made of plastic or glass. They're great for protecting individual plants, such as basil. Some cloches are airtight, offering more frost protection, but these need to be removed during sunny days so plants don't overheat. For less maintenance, choose cloches that are vented on top. They won't protect plants from freezing temperatures as well as closed cloches, but plants are less likely to be burned from excessive heat during the day.
* Cold Frame. A simple, homemade cold frame can be constructed from a 3-foot-wide by 6-foot-long wooden box, or even by hay bales arranged in a box shape. Place an old window sash, piece of translucent plastic, or plexiglass on top. More elaborate prepackaged cold frame boxes are made of fiberglass, metal, or wood and sometimes have automatic vents. The best location for your cold frame is a south-facing, protected spot, such as the side of a garage. Amend the soil well with compost before planting.
In warm areas you can still plant vegetables and flowers for winter and spring harvests. Locate your fall gardens in warmer microclimates, such as on the south side of a rock wall or in a protected nook near your house or garage. These areas are often protected from cold winds and stay warmer in the fall. In USDA zones 8 and warmer, plant vegetables such as arugula, beets, garlic, kale, lettuce, onions, peas, radishes, spinach, and Swiss chard. The greens and root crops can be harvested through the winter, while garlic and onions will mature next summer.
In all areas, spring-lowering bulbs, such as tulips and daffodils, should be planted six weeks before you expect the ground to freeze. Transplants of snapdragons, primroses, ornamental kale and cabbage, pansies, and violas make great additions to a fall garden. In warm areas they will flower all winter, while in cold areas they may survive the winter and flower again in spring if you cover them with a thick layer of mulch.