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Cold-Hardy Winter Vegetables Pam Dawling 2013, Twin Oaks Community, Virginia Author of Sustainable Market Farming Published by New Society Publishers SustainableMarketFarming.com facebook.com/SustainableMarketFarming

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Whats in this presentation Why farm in winter? Tables of cold-hardiness Four situations for cold-hardy crops Details of suitable crops Scheduling outdoor crops Weather prediction and dealing with it. Protection Hoophouse growing in winter Storage Resources My contact info

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Why grow winter vegetables? People eat all year long! Winter share CSAs are more in demand as the locavore movement grows, There is a year-round demand for local foods in stores and markets. Keep your customers, Keep your crew, Its easier than the summer - you have fewer crops to take care of. Weeds grow slower in colder weather, planting dates may become more flexible,

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Before taking the plunge into winter gardening know your climate, know your resources, know your market, know your crops (the main focus of this presentation), when you dont know, experiment on a small scale.

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Winter Hardiness Table Frosty Weather Some starting numbers of killing temperatures, although your own experience with your soils, microclimates and rain levels may lead you to use different temperatures: 35F (2C): Basil. 32F (0C): Bush beans, cauliflower curds, corn, cowpeas, cucumbers, eggplant, limas, melons, okra, some pak choy, peanuts, peppers, potato vines, squash vines, sweet potato vines, tomatoes. 27F (3C): Most cabbage, Sugarloaf chicory (takes only light frosts), radicchio. 25F (4C): Broccoli heads, chervil, chicory roots for chicons and hearts, Chinese Napa cabbage, dill, endive (hardier than lettuce, Escarole more frost-hardy than Frise), annual fennel, large leaves of lettuce (protected hearts and small plants will survive even colder temperatures), some mustards and Asian greens (Maruba Santoh, mizuna, most pak choy, Tokyo Bekana), onion scallions.

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Colder 22F (6C): Arugula, tatsoi (both may survive colder than this). 20F (7C): Some beets, cabbage heads (the insides may still be good even if the outer leaves are damaged), celeriac, celtuce (stem lettuce), perhaps fennel, some mustards/Asian greens Tendergreen, Tyfon Holland greens), radishes, turnips with mulch to protect them (Noir dHiver is the most cold-tolerant variety). 15F (9.5C): Some beets (Albina Verduna, Lutz Winterkeeper), beet leaves, broccoli leaves, young cabbage, celery (Ventura) with rowcover, cilantro, endive, fava beans (Aquadulce Claudia), Russian kales, kohlrabi, Komatsuna, some lettuce, especially small and medium-sized plants (Marvel of Four Seasons, Rouge dHiver, Winter Density), curly leaf parsley, flat leaf parsley, Asian winter radish with mulch for protection (including daikon), large leaves of broad leaf sorrel, turnip leaves, winter cress.

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Colder still 12F (11C): Some cabbage (January King, Savoy types), carrots (Danvers, Oxheart), most collards, some fava beans (not the tastiest ones), garlic tops if fairly large, most fall or summer varieties of leeks (Lincoln, King Richard), large tops of potato onions, Senposai, some turnips (Purple Top). 10F (12C): Beets with rowcover, purple sprouting broccoli for spring harvest, brussels sprouts, chard (green chard is hardier than multi-colored types), mature cabbage, some collards (Morris Heading), Belle Isle upland cress, some endive (Perfect, President), young stalks of bronze fennel, perhaps Komatsuna, some leeks (American Flag), Asian winter radish, (including daikon), rutabagas, (if mulched), large leaves of savoyed spinach (more hardy than flat leafed varieties), tatsoi.

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Coldest 5F (15C): Garlic tops if still small, some kale (Winterbor, Westland Winter), some leeks (Bulgarian Giant, Laura, Tadorna), some bulb onions (Walla Walla), potato onions and other multiplier onions, smaller leaves of savoyed spinach and broad leaf sorrel. 0F (18C): Chives, some collards (Blue Max, Winner), corn salad, garlic, horseradish, Jerusalem artichokes, Vates kale (although some leaves may be too damaged to use), Even Star Ice-Bred Smooth Leaf kale, a few leeks (Alaska, Durabel), some onion scallions (Evergreen Winter Hardy White, White Lisbon), parsnips, salad burnet, salsify, some spinach (Bloomsdale Savoy, Olympia, Tyee).

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Four situations Cool weather spring/fall crops to harvest before very cold weather Crops to keep alive as far into winter as possible Hardy winter-harvest crops Overwinter early spring-harvest crops

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Cool weather spring/fall crops to harvest before very cold weather Some crops grow in spring and again in the fall Asian greens, beets, broccoli, cabbage, carrots, chard, collards, kale, kohlrabi, lettuce, peas, radishes, rutabagas, scallions, spinach, turnips. Bed of young Danvers carrots. Credit Kathryn Simmons

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Crops to keep alive as far into winter as possible Many greens and roots can survive some freezing, so it is worth experimenting to find how late you can keep crops outdoors. Use the table to get an idea of what to expect. Celeriac takes 20F (7C ) Large Smooth Prague celeriac. Credit Southern Exposure Seed Exchange.

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Broccoli and cabbage It can be hard to think about sowing seeds in midsummer, but its really worth making the effort to grow fall brassicas because as they mature in the cooler fall days they develop delicious flavor. And weeds and pests slow down then, too once established these crops need little care. The most challenging part of growing fall brassicas is getting the seedlings growing well while the weather is hot. Unlike some cool-weather vegetables such as spinach, brassicas actually germinate very well at high temperatures: the ideal is 77F85F (25C29C), but up to 95F (35C) works. Cabbage bed, credit McCune Porter

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Lettuce Heat-tolerant varieties also tolerate cold. There are also specialized cold-hardy varieties that do not tolerate heat (because they have a relatively low water content). Sow these in fall and winter only. Choose your site with care. Protection from prevailing winds can be vital. Conserve soil warmth by using light- colored mulches - reduce radiation losses. Rowcover will provide a temperature gain of 46 degrees F (2.23.3 degrees C), depending on the thickness. It also reduces light transmission and airflow, but the trade-off can be very worthwhile. Lettuce may survive an occasional dip to 10F (12C) with good rowcover but not 8F (13C), I can tell you! Adolescent lettuce are more cold-hardy than full-sized plants. Varieties for fall and winter Particularly cold-hardy for outdoors: Brune DHiver, Cocarde, Esmeralda, Galactic, Hyper Red Wave, Integrata, Kalura, Lollo Rossa, North Pole, Outredgeous, Rossimo, Rouge dHiver, Sunfire, Tango, Vulcan and Winter Marvel. The Salad Bowls are not so good outdoors in cold weather but do very well under cover. Icebergs do not survive frost. Rouge dHiver Lettuce, Credit SESE

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Cold-hardy Asian Greens Tatsoi/tah tsoi - a small, flat rosette of shiny, dark green spoon-shaped leaves and white stems. We usually direct sow this and then thin into salad mixes, leaving some to mature at 10" (25 cm) across for cooking greens. We also transplant at 6" (15 cm) if that suits our space better. It has a mild flavor, an attractive appearance, and is easy to grow. Tatsoi is extremely cold tolerant, hardy to 22F (6C). Kitazawa Seeds have a Red Violet tatsoi, with an upright habit. Tatsoi takes 21 days to become baby salads; 45 days to reach cooking size; Yukina Savoy - like a bigger tatsoi, with blistered dark green leaves, greener stems and delicious flavor, about 12 (30 cm) tall. It is both heat and cold tolerant. We transplant this at 12" (30 cm). It needs 21 days to reach baby size, 45 days to full size; Tatsoi, Yukina Savoy, Senposai Credit Ethan Hirsh Komatsuna - also known as mustard spinach and Summer Fest. Green or red, a large cold- tolerant plant 18" (45 cm) tall. Individual leaves can be picked and bunched, or the whole plant can be harvested. The flavor is much milder than the English name suggests. Baby salad size in 21 days, full size in 35 days; Senposai is quite heat and cold tolerant, a big plant with large, round, mid-green leaves. Usually harvested leaf-by-leaf. It can be very productive. Transplant it at 12"18" (3045 cm) spacing. Cooks quickly (much quicker than collards), and has a delicious sweet cabbagey flavor and tender texture. It is a cross between komatsuna and regular cabbage. It takes only 40 days to mature. In spring the order of bolting of Asian greens is: tatsoi, pak choy, Komatsuna, mizuna, leaf radish, mustards.

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Turnips and rutabagas Rutabagas can be stored in the ground (unlike turnips, except in warm climates). Mulch over them with loose straw once the temperatures descend near 20F (7C). If you dont manage to eat all the roots before spring, they will re- sprout and you can have an early spring bite of greens (a term more usually used for cattle fodder crops). Turnips do very well in the winter hoophouse. We sow our first ones Oct 15 (around our first frost date) for harvest from Dec 4. We like Red Round and Hakurei and have tried out Oasis and White Egg to find a cheaper replacement for Hakurei (Oasis is the closest). We do a second sowing Nov 9 and a small third sowing Dec 10. We also grow Purple Top White Globe outdoors in spring and fall. White Egg turnip. Credit Southern Exposure Seed Exchange

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Hardy winter-harvest crops For crops to harvest all winter long, look for ones that will survive your lowest temperatures, taking any rowcovers or other crop protection into account. If you can add some wind protection, do so. Look for the hardier cultivars available. At our Zone 7 farm, we overwinter Vates kale without rowcover, but weve killed off Winterbor and Russian kales that way, while we were learning. We grow our winter-harvest crops in our raised bed area, which is more accessible in winter and more suited to small quantities. Each bed is 90' 4' (27.4 1.2 m) and fits four rows of most crops, but three of the bigger collards. Vates kale Credit Kathryn Simmons

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Our favorite cold-hardy winter-harvest crops Collards, kale, leeks, parsnips and spinach all survive outdoors without rowcover at our farm (Zone 7). We harvest small amounts throughout the winter, and when spring arrives, the plants give us big harvests sooner than the new spring- sown crops. We use double hoops and rowcovers and pick spinach throughout the winter, whenever leaves are big enough. We usually have about seven beds and can pick one each day in October, November, February and March, when the weather is not too awful to go out. Spinach will make some growth whenever the temperature is above about 40F (5C), so we can also make occasional harvests in December and January. We have also successfully overwintered carrots and Deadon cabbage. Overwintered Vates kale

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Winter-harvest leeks Unlike onions, leeks will grow independently of day length and will stand in the field at temperatures below what many other vegetables can handle, increasing in size until you choose to harvest them. Overwintered leeks. Leek varieties - two main types: the less hardy, faster-growing varieties, often with lighter green leaves, which are not winter-hardy north of Zone 8, the blue-green hardier winter leeks. Giant Musselburgh (105 days) is bolt-resistant, for overwintering in milder climates. For winter leeks we like Tadorna (100 days), Jaune du Poiteau, King Sieg (84 days, a cross between King Richard and the winter-hardy Siegfried, from Fedco) and Bleu de Solaize (105 days, very hardy).

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More hardy winter-harvest crops Small greens such as arugula, parsley, Belle Isle upland cress, winter purslane, salad burnet and mache (corn salad) are very winter-hardy too. More unusual crops like horseradish, Jerusalem artichokes, salsify, some endive are hardy. Walla Walla bulb onions and Evergreen Winter Hardy White or White Lisbon onion scallions are surprisingly hardy. Swiss chard is hardy to 15F (10C) without rowcover. To keep chard in best condition overwinter, either cover with hoops and rowcover (in mild areas, Zone 6 or warmer), or else mulch heavily right over the top of the plant, after cutting off the leaves in early winter. It germinates best at 85F (29C), useful as a substitute if the fall is too hot to sow spinach. Bright Lights chard. Credit Wren Vile

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