Winter-Kill Temperatures of Cold-Hardy Vegetables 2025 revision

My scheduling program lost my post. Sorry. I won’t use that one again.

Here’s my table of winter-kill temperatures of cold-hardy vegetables (2025 revision). Not a lot has changed in the past year. This is the time of year to plan winter crops and even start them (apart from leeks and parsnips, which need sowing in spring).

I’ve added a few other resources people often want when planning winter crops: Four Ranges of Cold Hardiness; Rowcover Notes; Hoophouse Notes; Cold-Hardy Lettuce.

I compiled this as a handout to accompany my presentation for the Seedtime Winter Garden Challenge event.

Winter Garden Challenge Handout   

© Pam Dawling 2026.  Twin Oaks Community, Central Virginia (zone 7a)

Author of Sustainable Market Farming, 2^nd edition and The Year-Round Hoophouse.

SustainableMarketFarming.com

Winter-Kill Temperatures of Cold-Hardy Vegetables 2025 revision

Here are some starting numbers of outdoor killing temperatures of unprotected crops (except where stated). Note that repeated cold temperatures can kill off crops that can survive a single dip to a low temperature, and that cold winds, or cold wet weather can destroy plants quicker than simple cold.  All greens do a lot better with protection against cold drying winds.  Your own experience with your soils, microclimates and rain levels may lead you to use different temperatures in your crop planning. This version includes cover crops.

• 35°F (2°C): Basil
• 32°F (0°C): Bush beans, cauliflower curds, corn, cucumbers, eggplant, lima beans, melons, okra, some pak choy, peanuts, peppers, potato vines, southern peas, squash vines, sweet potato vines, tomatoes.
• 27°F (–3°C): Many cabbages, sugarloaf chicory (takes only light frosts)
• 25°F (–4°C): Some cabbages, chervil, chicory roots for chicons and hearts, Chinese Napa cabbage (Blues), dill (Fernleaf), some fava beans (Windsor), annual fennel, some mustards and Asian greens (Red Giant, Southern Curled, maruba santoh, mizuna, most pak choy), some onion scallions (many varieties are hardier), radicchio, rhubarb stems and leaves.
• 22°F (–6°C): Some arugula (some varieties are hardier), Bright Lights chard, some endive, large leaves of lettuce (protected hearts and small plants will survive colder temperatures).
• 20°F (–7°C): Some beets (Bulls Blood, Chioggia), broccoli heads (maybe OK to 15°F/−9.5°C), some Brussels sprouts, some cabbages (the insides may still be good even if the outer leaves are damaged), celeriac, celtuce (stem lettuce), some collards (Georgia Cabbage Collards, variegated collards), some head lettuce, some mustards and Asian greens (Tendergreen, Tokyo bekana, Tyfon Holland greens), flat leaf parsley, radicchio (both Treviso and Chioggia), radishes (Cherry Belle), most turnips (Noir d’Hiver is the most cold-tolerant variety). Canadian (spring) field peas are hardy to 10-20°F (–12 to –7°C).

  

• Large oat plants will get serious cold damage, and oats seedlings die at 17°F (–8°C).
• 15°F (–9.5°C): Some beets (Albina Verduna, Lutz Winterkeeper), beet greens, some broccoli, some cabbages (Kaitlin, Tribute), some cauliflower leaves, rowcovered celery (Ventura), red chard, cilantro, some fava beans (Aquadulce Claudia), Russian kales, kohlrabi, some lettuces (Marvel of Four Seasons, Rouge d’Hiver, Winter Density), especially small plants with 4–10 leaves, curly parsley, rutabagas (American Purple Top Yellow, Laurentian), broad leaf sorrel, most covered turnips, winter cress.
• 12°F (–11°C): Some beets (Cylindra,), some broccoli, some Brussels sprouts, some cabbages (January King, Savoy types), carrots (Danvers, Oxheart), most collards, some fava beans (mostly cover crop varieties), garlic tops if fairly large, Koji greens, most fall or summer varieties of leeks (Lincoln, King Richard), large tops of potato onions, covered rutabagas, senposai leaves – the core of the plant may survive 10°F (–12°C), Purple Top turnips.
• 10°F (–12°C): Covered beets, Purple Sprouting broccoli for spring harvest, a few cabbages (Deadon), green chard (hardier than other colors), some collards (Morris Heading), Belle Isle upland cress, some endive (Perfect, President), young bronze fennel, Blue Ridge kale, probably komatsuna, some leeks (American Flag, Jaune du Poiteau), some covered lettuce (Pirat, Red Salad Bowl, Salad Bowl, Sylvesta, Winter Marvel), covered Asian winter radish (Daikon, China Rose, Shunkyo Semi-Long survive 10°F/–12°C), big leaves of savoyed spinach (more hardy than flat leafed varieties), tatsoi, Yukina Savoy. Aprovecho Hardy turnip is hardy to 8°F (–13°C) and Ice-Bred White Egg is hardy to 6°F (–14°C), many Even’ Star greens varieties are OK down to 6°F (−14°C), Oats cover crop of a medium size die around 10°F (–12°C). Large oats will die completely at 6°F (–17°C) or even milder.

  

• 5°F (–15°C): Garlic tops even if small, some kale (Dazzling Blue, Winterbor, Westland Winter), some leeks (Bulgarian Giant, Tadorna), some unprotected small lettuces (Winter Marvel, Tango, North Pole, Green Forest), some bulb onions (Walla Walla), multiplier onions if not well-mulched, smaller leaves of savoyed spinach and broad leaf sorrel.
• 0°F (–18°C): Chives, some collards (Blue Max, McCormack’s Green Glaze, Winner), corn salad (mâche), garlic, horseradish, Jerusalem artichokes, Even’ Star Ice-Bred Smooth Leaf kale, a few leeks (Alaska, Durabel), some bulb onions, mulched yellow potato onions, some onion scallions (Evergreen Hardy White, White Lisbon), parsnips (probably even colder), salad burnet, salsify, some spinach (Bloomsdale Savoy, Long Standing Bloomsdale, Olympia).
• Walla Walla onions sown in late summer are said to be hardy down to –10°F (–23°C), but I don’t trust below 0°F (–18°C)
• Crimson clover is hardy down to 0°F (–18°C) or perhaps as cold as –10°F (–23°C)

  

• –5°F (–19°C): Vates kale survives although some leaves may be too damaged to use. Lacinato Rainbow Mix kale may survive.
• –10°F (–23°C) Austrian Winter Field Peas and Crimson clover (used as cover crops).
• –15°F (-26°C) Hairy vetch cover crop – some say down to –30°F (–34°C)
• –20°F (–29°C) Dutch White clover cover crops – or even –30°F (–34°C)
• –30°F to –40°F (–34°C to –40°C): Narrow leaf sorrel, claytonia and some cabbages (January King) are said to be hardy in zone 3. I have no personal experience of this.
• –40°F (–40°C) Winter wheat and winter rye (cover crops).

Four Ranges of Cold Hardiness

1. Crops to harvest before frosty weather (32°-25°F) and use or store 
2. Crops to keep alive in the ground into winter to 22°-15°F (-6°C to -9°C), then harvest to use or store.

Use Soon: Asian greens, broccoli, cabbage, chard, lettuce, radishes

Store: Beets, cabbage, carrots, celeriac, kohlrabi, winter radish (including daikon), rutabagas, turnips

3. Hardy crops to store in the ground and harvest during the winter. In zone 7, they need to be hardy to 0°-10°F  (-17.8°C to -12.3°C): Collards, horseradish, Jerusalem artichokes, kale, leeks, parsnips, scallions, spinach
4. Overwinter crops for spring/early summer harvests before the main season: Cabbage, carrots, chard, collards, garlic and garlic scallions, kale, multiplier onions (potato onions), scallions, spinach

   

Rowcover Notes

Rowcovers on hoops will help keep crops marketable, by improving the microclimate for better growth rate. Thick rowcover (Typar, 1,25 oz/sq yd) can keep crops 6F degrees, 3C degrees warmer. Hoops prevent crops freezing onto the rowcover. Polypro outlasts polyester. Consider Quick Hoops and caterpillar tunnels if they suit your climate and crops.

Hoophouse Notes

In a double-layer hoophouse (staying 8F/5C warmer than outside at night) plants can survive 14F/8C colder than they can outside, without extra rowcover; with thick rowcover (1.25 oz Typar/Xavan) at least 21F/12C colder than outside without. Salad greens in a hoophouse in zone 7 can survive nights with outdoor lows of 14°F (-10°C). Lettuce, mizuna, turnips, Russian kales, senposai, spinach, tatsoi, yukina savoy survived a hoophouse temperature of 10.4°F (-12°C) without rowcover, -2.2°F (-19°C) with; Bright Lights chard got frozen leaf stems. We only add rowcover when the outdoor low is forecast to be 8°F (–13°C) or lower.

Cold-Hardy Lettuce

Lettuce varieties for a solar-heated winter greenhouse or hoophouse in zone 7a: (hardiest are in bold) Buckley, Ezrilla, Green Forest, Green Star, Hampton, Hyper Red Rumple Waved, Marvel of Four Seasons, Merlot, New Red Fire, North Pole, Oscarde, Outredgeous, Pirat, Red Cross, Red Sails, Red Salad Bowl, Red Tinged Winter, Revolution, Rouge d’Hiver, Salad Bowl, Sylvesta, Tango, Winter Marvel, Winter Wonderland.

Particularly cold-hardy for outdoors:  Brune d’Hiver, Buckley, Ezrilla, Green Forest, Hampton, Lollo Rossa, Merlot, North Pole, Red Tinged Winter, Revolution, Rouge d’Hiver, Tango, Winter Marvel.

Cold-tolerant outdoor early spring lettuces: Buckley, Crawford, Green Forest, Hampton, Merlot, New Red Fire, Revolution, Simpson Elite, Susan’s Red Bibb and Swordleaf.