If we didn’t feel it already, last week’s East Coast snow blitz gave a sure sign that winter is on its way, bearing colder temperatures, wetter conditions and shorter days. Before you’re bundled in sweaters and dreading to leave the house, spare your garden the climate shock by taking the time now to dress it for the cold. By choosing the right crops, prepping the soil and providing a bit of shelter for weaker plants, fall and winter gardening can be surprisingly bountiful, despite the colder climate. And for gardens that close shop every winter, a little extra care now will start the spring off with rich, productive soil.
(If you don’t have a garden, try your hand at indoor gardening to enjoy fresh herbs and vegetables right from your windowsill).
Tidy up, but leave some plants standing.
Pull out and compost the old plant material, including dead roots, stems and foliage, which can nourish insects and diseases over the winter. If your region saw any outbreaks of late blight over the summer, help prevent the disease from spreading by removing and disposing of all potato and tomato plant parts. Leave any healthy brassicas standing. As they decompose in the spring, brassicas, including kale, broccoli, radishes and brussel sprouts, all release cyanide
compounds that kill wireworms and other pests. In the flower garden, leave a few dead stalks to give local birds seeds to munch on, and leave a few brush piles and dead groundcover to provide beneficial insects with winter shelter.
Feed and test the soil.
After crop debris has been pulled, spread a layer of compost, which helps insulate the soil from the cold while providing food for soil microbes throughout the winter. It’s also a good idea to test the soil’s pH levels and sprinkle lime if it comes up overly acidic.
Mulch is the ultimate winter coat for the garden. Not only does it help maintain soil temperature, keeping plant roots warmer, but it also prevents winter weed growth and protects the soil from erosion during winter storms. Mulch also helps make winter vegetable growth possible in regions where the soil freezes, as long as it’s in place before the first freeze. Mulching materials include peat moss, bark, sawdust and coconut fiber. Lay down one to two inches over the soil and around plant bases. Periodically check the moisture level under the mulch to ensure plants are getting enough water. Uncover the soil as the temperature rises in early spring to allow it to warm for the next round of seeds.
Plant cold-tolerant crops.
Believe it or not, quite a few garden vegetables actually thrive in colder weather, including all of the brassicas as mentioned above, but also root crops like carrots, onions, potatoes and leeks. Winter has its fair share of seasonal greens as well, including spinach, mustard and Swiss Chard. For optimal planting dates, count back the number of days required for the variety to reach maturity from your region’s average first frost date, and add ten days to account for fall’s fewer daylight hours. In general, plants that reach 90 percent maturity before cold temperatures set in are more likely to survive. Up your chances of a successful harvest by planting seeds in succession over a two week period with a handful of varieties.
Consider cover crops.
Also known as green manure, cover crops like alfalfa, wheat, arugula and oats, keep soil microbes active over the winter, prevent weeds and help combat erosion. Most fall cover crops reach maturity in four weeks, but cereal rye can be planted up until the first frost. In the spring, cover crops can be tilled into the soil or pulled before going to seed.
Protect young and vulnerable plants from the elements.
Sudden cold snaps, downpours and windy days can damage plants and encourage mold and fungal diseases. Fortunately, you don’t have to haul the entire garden indoors or build an elaborate greenhouse to keep plants healthy. Simple shelters in the form of cloches, cold frames and row covers can help to gradually acclimate tender plants to the cold, requiring minimal effort and investment while significantly extending the growing season.
A cloche is simply a portable and translucent cover that uses solar energy to warm the plants underneath. Manufactured cloches can be purchased at most garden centers, but they can also be made from the bottoms of plastic beverage bottles and milk jugs. Be sure to remove the cover on warm and sunny days to avoid detrimental heat build up.
Also known as floating row cover or garden fabric, these polypropylene sheets can be draped directly over garden beds to protect young plants and tender perennials from the cold while keeping pests and diseases at bay. Look for products that allow overhead moisture to seep through, or try old sheets, blankets and afghans.
A cold frame can be any four-walled structure with a transparent lid that allows in light. The simple design retains heat, shelters plants and can increase the growing season by up to two months. Under a cold frame is the ideal place to overwinter tender perennials and to harden off (or gradually acclimate) indoor starts for planting in the spring. Any old window sash or a sheet of plexiglass can be recycled as a lid for the cold frame, and the walls can be made from a variety of sturdy materials, such as plywood, concrete or even bales of hay. The frame should be several inches higher in the back so that the lid lies on a downward slope, allowing rain to run off and maximizing light exposure. If possible, position the frame against the southern exposure of the house or shed to help the structure gather heat and retain warmth. As the weather warms, prop open the lid for ventilation.