A good friend and pretty experienced gardener recently asked me if it was too late to plant lettuce. Her question reminded me that there is considerable ambiguity about planting greens in the late summer/early fall. There shouldn’t be; September and October present perfect, in many years, the most perfect conditions for the germination and growth of all types of greens. While there’s some risk that an early frost, or cold snap might stop your seedlings in their tracks, the fall weather we usually end up getting in the Northeast is as close to ideal as it gets. We are so accustomed to thinking of the heat of July and August as prime gardening time, that it’s easy to forget that what’s prime for tomatoes and peppers is not so good for greens. Lettuce, kale, mustards, arugula, watercress all long for the cooler, more likely to be rainy weeks following Labor Day. If you garden in a greenhouse, you have even more to gain from seeding greens than the rest of us—what you sow now will be flourishing into the depths of winter.
Mustard Greens are a fall favorite of mine. ‘Renee’s Mild Mustard Mix’ includes four different types—I sowed them in late August, and have included their tasty (all are milder when cooked) leaves in my menus for the past few weeks. Renee’s Seeds offers several intriguing mixtures, including ‘Renee’s Beet and Chard Braising Mix,’ and an ‘Oriental Stir-Fry Mix’ that are harvest-ready in the 40-day range. Territorial offers my favorite mustard, the frilly ‘Green Wave,’ a delightful salad green when the leaves are still medium-sized. I also planted a row of Bok Choy– I’ll use thinnings in stir-fries until they size up. Larger Bok Choy is great for Asian-inspired slaw –slice thinly with carrots and red peppers, and dress with lime juice and cilantro—which is also thriving in the cooler, wet weather in my garden. Kale is another green I can’t have too much of—this year I planted both ‘Nero de Toscana,’ a dark-leaved Italian heirloom, and the colorful ‘Red Winterbor.’
And then there is lettuce, the question that originally prompted my thoughts. There’s definitely a point beyond which lettuce seedlings simply stop growing, as days shorten and nights turn crisp. But I suggest seeding until that point becomes clear. This past spring I harvested lettuce for six weeks from plants that overwintered—not something to rely upon, but perhaps with climate change, a more frequent occurrence than it once was.