With a muted sigh of relief, many gardeners are frankly happy to lay down their tools at the end of summer’s growing season. But for those of us who like to eat from our own gardens, the approach of winter can mean a reluctant return to store-bought produce. It is possible, however, to garden right through to next spring if we start right away.
In fall, winter and very early spring, we can garden without fighting weeds and insects. We need to protect plants from the coldest temperatures, and we have to select hardy varieties. We must sow with the realization that even the hardiest plants will survive but not actually grow—that is, increase in size—during the coldest periods.We need to get started as soon as possible so that the plants we will eat through the winter can get well established before our really cold weather.
There are lots of ways to protect plants from cold, as Eliot Coleman describes in his Four-Season Harvest. (If he can do it in Maine, we can certainly do it here!) A cold frame is cheap and easy, just a couple of old storm sash windows atop a shallow wood box. Even simpler is heavyweight row-cover fabric such as Agribon AG-19 stretched over 76-inch lengths of heavy (9- or 10-gauge) wire, bent into arches. The row-cover fabric forms a protective tunnel over a row of plants. This works even better if you lay down a plastic solar mulch to warm the soil with drip irrigation under it.
A small hoophouse is no more than 6- to 8-foot high arches made from metal or plastic tubing, covered with clear plastic. My personal favorite is a cheap ($400) plastic Germinator “greenhouse” that is 8-feet square with shelves on both sides. I use this to start seeds in early spring, and eat salads from it all winter. My root crops, planted in late summer, are protected by a cold frame. A heavy straw mulch works, too. Just cover the plants with a 6-inch layer of straw, tucking it close around the base of the plant.
The choice of fall and winter crops is wider than you might think. Lettuce actually prefers cooler weather, and varieties such as Arctic King, Winterwunder, Continuity, and Winter Density will tolerate (with protection) all but our worst winters. It’s a little late to plant transplants of cabbage, broccoli, and Brussels sprouts, although you might want to take a chance with them. Kale will stand the coldest weather we get; I’ve literally dug it out of the snow.
If you plant a hardy turnip, such as Purple Top White Globe, you’ll have baby turnips in time for Thanksgiving; with a straw mulch you can eat them deep into winter. Peas love our fall temperatures, and are frost tolerant down to 20 degrees Fahrenheit. Beets sown now will, at the very least, give you some nice leafy tops and may have time to form baby roots. Radishes can be sown weekly for a continuous harvest, but they won’t tolerate a freeze.
Winter greens are something to look forward to. Arugula is a reliable standby, but be sure to try mache, also called corn salad; upland cress, the peppery leaves of which are rich in vitamin C and very cold hardy; miner’s lettuce, or claytonia; spinach; and Fordhook Giant Swiss chard. Many Asian greens are cold tolerant, including Kyoto mizuna, Osaka purple, hon tsai tai, and tatsoi. All of these will flourish under rowcovers or in cold frames, hoophouses, or small greenhouses.
Overwintering plants use much less water than summer crops, so take care not to give them more than they need. Avoid getting water on the leaves, because this amplifies the effect of cold weather and may shock the plant. If you fertilize at all, use a half-strength mixture of a fish-seaweed product.
Harvest with particular care, bearing in mind that most plants will not regrow in cold conditions. Using sharp scissors, snip an outer leaf here and there, leaving enough to let the plant make the most of the weak winter sun. Pick a pea, pull a radish or beet, and savor every morsel as you look forward to spring.