To us, the days are getting shorter, but to plants, the nights are getting longer. The cool and dark allow them to regenerate and to build new cells. Perennials start maturing their roots and sap for winter. Some are programed genetically to bloom or stop blooming in response to the longer dark. Even heat-lovers like tomatoes actually shut down at 90 degrees, so with more time to cool off, many plants have a sort of second spring. Some spring bloomers bloom again.
This is our cue to plant seeds for fall. The possibilities include all of the spring favorites like lettuce, peas, and broccoli. But fall is not just a lesser version of spring. There are good reasons to plan the fall garden as a season all its own, with delicacies and opportunities that spring doesn't have.
First, there are plants that are very hard to grow in spring but easy in the fall. Spinach, bulbing fennel, and Nappa cabbage are day-length-sensitive plants that bolt and get bitter quickly in spring. In the shortening days of fall, they stay in vegetative growth, producing juicy, succulent vegetables for the table. Nappa cabbage is especially easy and quick. Its crunchy, juicy leaves are as mild as lettuce but hardier--good in salads, coleslaw, stir-fries, sandwiches, and preserved as kim-chee. Fennel is like a sweeter, more aromatic celery—and much easier to grow. Homegrown spinach is sweeter, and juicier than what's in the store. And instead of one quick spring harvest, you can cut leaves all winter. The entire chicory/endive tribe is as easy to grow as lettuce when you sow in the fall.
Kale, cabbage, and broccoli sprout and grow best in fall. As young plants, they prefer warm weather, when their seeds would naturally fall to the ground and sprout. (They develop their great cold-hardiness as adult plants.) Transplanting is not a problem for this group—it actually stimulates root growth. Starting them in a shaded nursery bed is nice because it doesn't demand the care that pots do—and they'll wait for their garden space without getting pot-bound. If you need to use pots or flats, plan on giving them afternoon shade, and transplant to the garden or a larger pot within a month. Or sow them in large pots to start with.
Plant peas deeper than in spring, so they stay moist—about 1” deep. Soaking the seed for a couple of hours helps too. If you want to cut the tips for salad greens, it's best to plant a separate patch and harvest the top 4" of new growth. You can cut repeatedly once the plants are at least 16" tall.
Lettuce is probably the crop that will save you the most trips to the store if you grow it at home. So I like to plant it where I can reach it easily in the dark after work, or in the rain. Sow some every 2 weeks til frost. Its hardier, richer-tasting relatives--radicchio, chicory, and endive--are staples of the Italian winter kitchen. I love their slightly bittersweet flavor (like walnuts) in salad, pasta sauce or braised. They are a welcome change from the mustardy flavors that dominate winter greens. Winter lettuces and endives are bred to resist rain, mildew, and mold, as well as to be cold-hardy.
Lettuce is the opposite of kale. It wants to sprout in spring. So fool it. Put your packet of lettuce seeds in the fridge for a week. That artificial winter gets it ready to sprout. Sow in the evening, water well, and give it afternoon shade--an artificial spring that will gently introduce your lettuce to the realities of fall.
Jamie Chevalier lives and gardens on a river in the Coast Range. She has gardened professionally in Alaska and California, as well as living in a remote cabin and commercial fishing. She wrote the Bountiful Gardens catalog from 2009 to 2017, and now is proprietor of Quail Seeds.