Winter Garden: How to Time Plantings

There are even winter-hardy lettuces: this is Brune D'Hiver ("winter brown")

Unlike summer vegetables, which tend to be New World annuals (or tender perennials) like corn, tomatoes, peppers, green beans and zucchini squash, most winter vegetables are Old World biennials which need to over-winter in order to flower and produce seed during their second year.

Old varieties of chicory, kale, many cabbage family relatives as well as root crops like radish, turnip & carrots have provided Europeans with fresh winter vegetables since ancient times. It is always fun to experiment with which varieties grow best in Philadelphia winters, but timing when to plant can be tricky.

When planning your winter vegetable garden, keep in mind that even frost-hardy plants slow and almost stop growing when there are less than 10 hours of daylight per day. In Philadelphia, which is longitude 40 degrees (same as Madrid, the “boot” of Italy, Greece and Denver) this happens November 11 through January 20.

Therefore, you want your plants to reach maturity before November 11, even though it is fine to continue to harvest through this “dark” period. Look at your seed packets for “days to maturity” and subtract that from November 11 to get the last date you can plant that particular variety. This will give you a general timeframe and a “last date” to plant, but of course you can always plant earlier, depending on heat and bugs and whether you have space to plant or have to wait till something else finishes producing.

The longest-maturing plants for me this winter are brussels sprouts and radicchio (90 to 110 days to maturity). My friend Amy is setting up gro-lights in her basement and we are going to plant this weekend (July 21-22). The plants should be big enough to put out in the garden before it’s time to start the kales & collards in late August (these take about 60 days to maturity). The reason we are starting seed indoors is neither of us has any unused garden space right now and we want to avoid harlequin bugs and the searing heat and drought of late July/August.

Direct-seeded things like carrots, winter lettuce & arugula can be planted in Aug/Sept, while turnips, beets & spinach go in Sept/Oct. A little mulch will give them additional winter protection. Winter spinach won’t germinate unless it is quite cool (look for a variety called Gigante D’Inverno — “giant of winter”), so it should be planted late (mid Oct or later).

There are many pleasures in winter gardening — the weather is cool and refreshing, the skies turn deep blue and autumnal, the bugs have closed up shop for the season, you seldom have to water — and the thrill of harvesting ingredients for a fresh salad in mid-December just can’t be beat!

And many winter-hardy plants get even sweeter and better-tasting after the first frosts: apparently sugar is a mild anti-freeze and many plants convert some of their starches to sugar with the onset of cold weather. Kale and collards are great examples of veggies that taste even better after they are kissed by a frost or two.

NOTE: My source on winter gardening is Eliot Colman’s Four-Season Harvest. Eliot grows veggies commercially in Maine throughout the winter in unheated poly-tunnels, but since Philadelphia is so much milder, we don’t have to bother with much of the paraphernalia that Eliot is forced to use.

NOTE2: Winter veggies you might consider: Arugula, Winter Spinach (has thick, extra-large, crinkly leaves), Cabbage (including the oriental cabbages), Kale (Tuscan & Red Russian are especially good), Carrots, Beets, Turnips (including oriental turnip and mustard greens), Winter Lettuces, Radicchio, Endive, Radishes (Daikon & Chinese “Beauty Heart” are an interesting change from the small red & white ones), all kinds of Chicory, Broccoli Rabe, Brussels Sprouts, Collards, Escarole, Sprouting Broccoli, Dandelion Greens, Garlic (harvest in the spring), Fava (harvest in late spring), Chard (your summer chard will survive the winter if you leave it in the ground), Peas & Snow Peas (a before-Christmas treat), and others which I don’t have the space to mention…

…Oh, and don’t forget that early fall is a great time to replant the cilantro and dill that went to seed and died during the heat of summer. If you have coriander seeds in your pantry, just plant those to get fresh coriander a.k.a. cilantro without having to order seeds. You can do the same with dill seeds if you have them.

–Barb Mc

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