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
Slide 2
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
Slide 3
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,
Slide 4
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.
Slide 5
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.
Slide 8
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).
Slide 9
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
Slide 10
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.
Slide 15
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
Slide 16
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
Slide 17
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
Slide 18
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).
Slide 19
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