Not ready to hang up your gloves and spade just yet?
The fearless gardener still has a chance to plant some cold-hardy vegetables to harvest next spring, says Jim Myers, plant breeder and researcher at Oregon State University.
But don’t dawdle.
“Winter gardening is a risky business,” Jim says. “It may work one year with a mild winter but not another when the weather is more severe. If you plant some cold-hardy vegetables from mid-August to early October, depending on the crop, there’s a good likelihood you will produce something on the other end in the spring. They say farming is a gamble—some years more than others.”
Cold weather doesn’t kill these hardy plants; it simply slows their growth rate. For every rise of 18 degrees, growth rate doubles—but that guideline only applies to an air temperature range of 40 to 98 degrees, Jim says.
If you plant cold-hardy vegetables in the fall, there is a chance they can mature by next spring if they survive in a vegetative state through the winter without reproducing.
He says the hardiest vegetables that can withstand heavy frost of air temperatures below 28 degrees include spinach, Walla Walla sweet onions, garlic, leeks, rhubarb, rutabagas, broccoli, kohlrabi, kale, cabbage, chicory, Brussels sprouts, corn salad, arugula, fava beans, radishes, mustard, Austrian winter peas and turnips.
Semi-hardy vegetables that can withstand light frost of air temperatures in the range of 28 to 32 degrees include beets, spring market carrots, parsnips, lettuce, chard, peas, Chinese cabbage, endive, radicchio, cauliflower, parsley and celery. The tops will die for beets, spring market carrots and parsnips, but the roots will tolerate lower temperatures.
Vegetables that contain the pigment anthocyanin—which gives them a vibrant red or purple color—are more resistant to rots caused by winter rains, Jim says. They include purple-sprouting broccoli, Rosalind broccoli and purple kale.
If you live in an area that gets prolonged snow cover, the fluffy white stuff acts as insulating mulch and warms the soil for these tough plants, Jim explains.
For areas that get a lot of rain in the winter, Jim recommends covering vegetables with high or low tunnels made from metal hoops and clear plastic, available at greenhouse supply companies. To protect plants, you also can use row covers or cloches. To warm the soil, use mulch made from yard debris, cardboard or newspaper.
Cross your fingers, and by next March, you could be feasting on a bounty of cold-hardy vegetables.