Root Crops in July

 

 

A fine rutabaga (Swede)!
Photo Produce Market Guide

Root Crops in July

Root Crops to Plant in Central Virginia in July

July is not a good month for sowing many root crops in Virginia – it’s hot and for most fall root crops we can do better waiting till August. Yes, it will still be hot in August, but the daylight is getting shorter and so the hot part of the day is also getting shorter. 

Carrots: if we really need more carrots, we direct sow our eighth bed of carrots in early July. We only do this if they’re really needed, because carrots grown in hot weather do not have the best flavor. They will not be sweet, they may even be bitter.  Our plan is to have grown enough between February and May to last us until late October, stored in perforated plastic bags in the walk-in cooler. But if earlier sowings weren’t all successful, or we ate unusually large amounts of carrots, we can find ourselves sowing them in July.

Use shadecloth to keep the soil damp, or water a lot. Carrot seed will germinate whenever the soil is below 95°F (35°C), provided you can keep the soil damp until the seedlings emerge. You won’t need to do daily watering for long: maybe only 4 days. We flame summer carrots on day 4 after sowing, because we have found that carrots can emerge on day 5 in summer temperatures, despite longer times given in the charts. See Root Crops in May for more about sowing and growing carrots, including pre-emergence flame weeding.

Young kohlrabi plants.
Photo Kathryn Simmons

Kohlrabi: Kohlrabi transplants successfully, unlike carrots and turnips, and this has usually been our method for fall crops. We have sown kohlrabi (Early Purple Vienna and Early White Vienna) in the week beginning July 2, for transplanting 8/3-8/9. Sowing in early August is also possible, for November harvests. Kohlrabi, like other brassicas, can be grown in spring or fall in our zone 7 climate. It’s not actually a root crop, rather a swollen stem, but I’m including it as an “acting root”

Rutabagas: This year we are growing rutabagas (also known as Swedes) again, after several years when we went with more turnips instead. Rutabagas are only sown here in late summer for winter storage. They take longer to grow to a good size than turnips do, so it is necessary to start earlier: 7/15-8/4 here, (mid-August at the latest), allowing 90-100 growing days before a hard freeze. Fall root crops sown too early in the summer can get woody. See the Special Topic for July below for all the details about rutabagas.

Root Crops to Harvest in Central Virginia in July

Potatoes: From mid-June onwards, we can harvest spring-planted potatoes as delicious “new” potatoes. See Root Crops in June for more on this. For maximum yields, hold off on harvesting until two weeks after tops have died. See next week’s post for all the details.

This garden worker loves washing beets!
Photo Wren Vile

Beets: We like to clear all our spring beets by the end of June, but sometimes the job flows over into July. Trimmed beets keep well in perforated plastic bags under refrigeration. Store beets at 32°F (0°C) and 95% humidity.

Carrots: Our third carrots (sown mid-March) should be cleared in early July if not before, and our fourth carrots (sown in late March) and fifth (sown in mid-April) will also be ready to harvest in July. I usually reckon on three months from sowing to harvest for carrots, but they can be faster in warm weather. Don’t leave them in the ground too long, or they will get woody. See Root Crops in June for more on carrots.

Kohlrabi: As with beets, we plan to harvest spring kohlrabi by the end of June, at 3” (7.5 cm) in diameter (or even up to softball size). They get too fibrous if left longer, so we will prioritize getting them up. The base of the globe can be tough, so cut either the wiry root just below the soil surface, or cut higher, leaving a small disc of the globe behind, attached to the taproot.

Turnips:  If we didn’t finish harvesting our spring turnips by the end of June, we really need to get them all up in early July. If we have more than we can eat in the next week, we store them in perforated plastic bags in the walk-in cooler, eating them during the summer. Turnips keep for about 4 months at temperatures close to freezing and humidity of 90-95%. Higher humidity will make them rot (rotting turnips are pretty unpleasant!)

Harvested Purple Top Milan and White Egg turnips.
Photo Pam Dawling

Other Root Crop Tasks in Central Virginia in July:

After all the spring-sown root crops are harvested, and the spring-sown greens have bolted, we prepare the emptied beds for summer or fall crops.

Preparing space for summer-planted crops

In July, we will be looking for beds to plant successions of lettuce, cucumbers, squash and beans; our fall brassica transplants, and our first transplants of fall and winter cabbage and Asian greens. In August, we’ll want beds for our last plantings of cucumbers, squash and beans, the never-ending lettuces, fall beets, turnips, winter radishes, kale, and collards. Harvesting the spring roots promptly and storing them gives us time to prepare the beds for their next crop.

Buckwheat cover crop in flower.
Photo Pam Dawling

Buckwheat

If we have 4 weeks or more before the next crop, we will sow a cover crop of buckwheat in the just-emptied beds. Buckwheat keeps the weeds down and feeds the soil (and the honeybees and other pollinating insects). If there are weeds or lots of crop debris, we will till deep enough to bury that plant matter, then broadcast the buckwheat at a rate of 2–4 oz/100 ft2 (6–12 gm/m2), give another shallow tilling, then water and stand back. If there are no weeds or crop debris, there’s no need to till: you can broadcast the seed, and rake it in before watering (and standing back!). As an alternative to broadcasting you can sow rows of buckwheat with the #22 plate on an EarthWay seeder.

Prepare stale seed beds for fall carrots

If you have less than four weeks before you need to sow or transplant the next crop, you can use the time to kill weeds with the stale seedbed technique. Prepare the bed as if you were about to sow, producing an even surface with a fine tilth (surface texture). Then water as if you had sown something, keeping the surface damp by watering as needed. As soon as you see tiny weeds germinating, hoe the surface very shallowly in sunny breezy weather and let the weeds dry out. Make a last hoeing the day before sowing the next crop. This is especially useful for carrots, scallions or anything with tiny seedlings, which cannot easily compete with weeds.

Another method of germinating and killing weed seedlings when there is no crop in the ground is tarping: cover the bed with an opaque waterproof cover after watering the soil. Weeds seeds germinate, but the weeds cannot grow without light and will die.

Solarizing with clear plastic. Photo Pam Dawling

Solarizing is another approach that works well in hot weather: cover the prepared bed with clear agricultural plastic, such as scraps of a hoophouse covering. The heat of the sun bakes any weed seeds near the surface, and also any disease spores or small pests. Larger creatures such as earthworms can burrow deeper into the soil (as they do anyway in hot weather).

Rutabagas, although these ones don’t have much in the way of necks, a usual distinguishing feature.
Photo Penn State

Special Root Crop Topic for July in Central Virginia: Rutabagas

Rutabagas need to be sown in July in central Virginia. To clarify: rutabagas (known as Swedes in the UK) are Brassica napus, closely related to most other brassica crops. Botanically, rutabagas are part swollen tap roots, part swollen stem (the upper portion of the vegetable which forms the neck, the distinguishing feature of rutabagas). There are secondary roots growing in two rows down the sides of rutabagas. Rutabagas are mostly yellow-fleshed with a tan and reddish or purplish skin, although there are white-fleshed varieties. They all have blue-green waxy, non-hairy leaves. turnips are Brassica rapa, like Chinese cabbage and mustards. Turnips come in a range of colors, white or yellow flesh, with white, purple, red or golden yellow skins. The leaves are bright grass green, usually hairy, and not waxy. Turnips do not have a neck or secondary roots growing off the turnip. Rutabagas have twice the nutrients of turnips. And take longer to grow.

Rutabagas are among the hardiest of vegetables, and can be left growing (or at least not dying) until all other crops have been harvested. The flavor improves after frost. For small plantings, plan on 10’ (3 m) per person. Yields of rutabagas can be 75-180 lbs of roots/100’, (35-80 kg roots/30 m): 50% higher than turnips.

Rutabagas come in very few varieties. Laurentian (95 days OP) has a deep purple crown and cream yellow bottom. The uniform 5–6″ (13-15 cm) roots have sweet pale yellow flesh. Joan (90 days, OP), looks similar to Laurentian, with the added advantage that it is somewhat tolerant to club root. Gilfeather (85 days, OP) is sold as a turnip, but is botanically a white rutabaga. Sweeter and later to mature than turnips, it doesn’t become woody even at softball size. Southern Exposure Seed Exchange also has American Purple Top (not to be confused with the Purple Top White Globe turnip) and the Lithuanian Nadmorska a large oval 90d OP.

Fine rows of rutabagas. See the distinctive necks.
Photo Nan Chase

Keys to growing mild, sweet-tasting rutabagas include cool temperatures, sufficient irrigation, and no competition from weeds or over-crowding. The optimal germination range is 59-95°F (15-35°C). Rutabagas are a little slower to germinate. We sow four rows in 4’ (1.2 m) wide beds. Seeds need to be 0.5” (1.2 cm) deep. When flea beetles or grasshoppers are a problem, use rowcover or insect mesh.

Early thinning is especially important for shapely well-developed rutabagas. Thin to 4” (10 cm) within 10 days of emergence, or at least by 1” (2.5 cm) tall, then to 10” (25 cm) when 2-3” (5-7.5 cm) tall. If not well-thinned, they will grow in odd shapes and be small. 

Boron deficiency causes the middles of the roots to turn brown. Many common weeds are in the Brassica family, and could harbor pests and diseases that could attack the crop, so use crop rotations, stale seedbeds and clean cultivation to remove the weeds.

Aphids, flea beetles, cabbage worms, harlequin bugs, and grasshoppers can all be a problem. Rutabagas have worse trouble with aphids than turnips. Brassica flea beetles are not the same species as the nightshade flea beetles often found on eggplant. Rowcovers or insect netting and the planting of insectaries (flowers to attract beneficial insects such as ladybugs) can help avoid the problems. Bt can be used for the caterpillars, soaps for the aphids and Nolo bait for the grasshoppers (except where banned in order to preserve rare species of grasshopper).

More information 

GrowVeg Rutabaga Growing Guide 

Written in Vermont: Gardener’s Path:

Written in Mother Earth News by Sara Pacher:

DIY Network

The main diseases of rutabagas (and turnips) are club-root, downy mildew, powdery mildew, rhizoctonia rot, bacterial scab, and blackleg. All except scab are fungal diseases. Organic methods of prevention are crop rotations and field sanitation (plowing in residues promptly, removing weeds). Club-root fungus is able to live in the soil for up to 10 years, so is hard to eliminate. Avoid all brassica crops in an affected field for 10 years, and be vigilant about eliminating brassica family weeds. (Develop a fondness for spinach, chard and beet greens!)

Our rutabagas are ready from mid-October. Rutabagas (but not turnips except in warm climates) can be stored in the ground all winter. Mulch over them with loose straw once the temperatures descend near 20°F (-7°C). If you don’t 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).

Rutabagas can store for as much as 6 months in perforated plastic bags under refrigeration. They do best stored above 95% humidity. Prompt washing before the soil dries on the roots will make them easier to clean later.

In the UK, rutabagas are not waxed as they are in North America. In fact, they store well without waxing, and I encourage you to try skipping the petroleum product.

Sliced rutabaga.
Photo Cornell

Ordering seeds! Seed Viability and Varieties New to us

I’ve been busy putting our seed orders together. As we grow so many different crops, it’s quite a time-consuming process. And I hate to buy too little and be out in the field on planting day, looking at an almost empty packet. Equally, I hate to buy too much, which either wastes money (if we throw the extra away), or else causes us to risk sowing seed that really is too old, and won’t do well. I keep a chart of how long different types of seed last:

Seed Viability

(From Sustainable Market Farming, (c) Pam Dawling, New Society Publishers, 2013)

     

Close this window

   “Opinions vary a bit about how many years seeds of different vegetables are good for. The fuller story is that storage conditions make a big difference. You can make your own decisions, weighing up the information supplied, your knowledge of how carefully you stored the seeds, the information on each packet about percentage germination when you bought it, and the economic importance to you of that particular crop. If you always transplant lettuce, as I do, you can risk one of your four varieties in that sowing coming up poorly, and just plant out more of the other three if it fails. Many seed catalogs include information about seed longevity, and so does Nancy Bubel in The Seed Starters Handbook.

www.chelseagreenFrank Tozer in The Organic Gardeners Handbook has a table including minimum, average, and maximum.

A simplified version is as follows:

  • Year of purchase only: Parsnips, Parsley, Salsify, and the even rarer Sea Kale, Scorzonera
  • 2 years: Corn, Peas and Beans of all kinds, Onions, Chives, Okra, Dandelion, Martynia,
  • 3 years: Carrots, Leeks, Asparagus, Turnips, Rutabagas
  • 4 years: Spinach, Peppers, Chard, Pumpkins, Squash, Watermelons, Basil, Artichokes and Cardoons
  • 5 years: most Brassicas, Beets, Tomatoes, Eggplant, Cucumbers, Muskmelons, Celery, Celeriac, Lettuce, Endive, Chicory.”

Rather than deteriorating with age, some very fresh seed has a dormancy that needs to be overcome by chilling (lettuce). Other seed contains compounds that inhibit germination. These can be flushed out by soaking in water for about an hour (beets).

Another of the challenges with seed ordering is converting between grams, ounces and seed counts. Here’s a helpful table of 1000 Seed Weight for 13 crops.

Our main seed suppliers are FedcoJohnny’s and Southern Exposure. Fedco has great prices, especially on bulk sizes, great social and political commentary in the catalog, and no glossy pages. Johnnys has some good varieties that Fedco doesn’t, and a ton of useful information tucked away on their website. Southern Exposure is best on southern crops and heat tolerant varieties which we can’t expect seed companies in Maine to specialize in. Plus, SESE are my friends and neighbors.

This year we are trying some new varieties. Generally we like to have some reliable workhorses that we know well, and trial a few new things, especially if we hear our favorite varieties are no longer available. Last year our Nadia eggplant couldn’t cope with the heat. For a while in early summer they didn’t grow at all – no new flowers, never mind new fruit. So next year, alongside Nadia I’m trying 3 that should deal better with heat. Florida Highbush is open-pollinated, from the Seed Savers Exchange. Epic and Traviata are hybrids from Osborne Seeds.

Epic eggplant from Osborne Seeds
Epic eggplant from Osborne Seeds
Traviata eggplant from Osborne Seeds
Traviata eggplant from Osborne Seeds
Florida High Bush eggplant from Seed Savers Exchange
Florida High Bush eggplant from Seed Savers Exchange
Sugar Flash Snap Peas from Osborne Seeds
Sugar Flash Snap Peas from Osborne Seeds

I also bought some Sugar Flash snap peas from Osborne. We have been big fans of Sugar Ann, but I’ve heard Sugar Flash is even better on flavor, yield and harvest period. We’re going to find out!

For a couple of years we really liked Frontier bulb onions as a storage variety for this climate and latitude (38N). Frontier disappeared from the catalogs of our usual suppliers and we tried Gunnison and Patterson. This year – no Gunnison! And we didn’t get a good test of Patterson last year, as we failed to weed our onions enough, after an initial enthusiastic good go at it. We were looking again at Copra, one we grew some years ago (before we found Frontier). I lucked out when I decided to see if Osborne had Gunnison, while I was shopping there. they didn’t, but they had Frontier! And then when I was shopping at Johnny’s, I found they did have some Gunnison for online sales only. So I ordered those too!

We’re also trying Sparkler bicolor sweet corn from Fedco and a drying bean I won’t name, as the seed is in short supply. And this year we’re hoping Red Express cabbage will prove to be a reliable little worker. We used to like Super Red 80, but had several years of poor results. Since then, none of the other red cabbages we tried have satisfied us in terms of size, earliness, productivity and flavor.

West Indian Gherkin Seeds (Cucumis anguiria) from Monticello
West Indian Gherkin Seeds (Cucumis anguiria) from Monticello

After a few years of poor pickling cucumbers, we’re going outside the box and trying West Indian Gherkins from Monticello, where they were grown by Thomas Jefferson (and some of the enslaved people, no doubt). These are not closely related to actual cucumbers, but are used similarly. I saw them growing in the Monticello garden when I was there for the Heritage Harvest Festival in September, and they are certainly robust and productive in hot humid weather. We’ll see how the pickles turn out!

My only other “impulse buy” was the Salanova Lettuce new at Johnny’s. They are 6 varieties of head lettuce designed to be used for salad mix at a single cutting. Quicker than  snipping rows of baby lettuce with scissors. More fun than plain lettuce heads. They are loose heads of small leaves in various shades of green and red, and two “hairstyles”: frizzy and wavy.

Salanova Lettuce from Johnny's Seeds
Salanova Lettuce from Johnny’s Seeds

Twin Oaks November Calendar (and December)

Garlic shoots emerging through the mulch in November

November -The End is in Sight

During the month

Lettuce Factory: Sow lettuce in hoophouse, for January transplants.

Write Thank You Letter to Paracrew (part-time workers)

Early November: Finish up sowing cover crops in Nov. Can sow winter wheat in early November (won’t winter-kill). Sow wheat or rye in carrot beds by 11/30(?), or if too late for cover crops, just spread carrot tops on beds.

Sow onions to overwinter in hoophouse.

Plant hard-neck garlic when soil temp at 4″ deep is 50°F, and mulch immediately, not too thickly.

Plant soft-neck garlic.

Plant leftover small garlic cloves for garlic scallions and garlic greens.

Potato onions: till beds.  11/1-12/1: Plant medium-size (1½-2” diameter) potato onions, at 6”, or wider if supply is limited.  Cover with ½-1” soil, then mulch. If planning a January planting of small potato onions, prep bed and roll mulch now.

Sow spinach (for spring harvesting) in early November if not done already.

Mid November: Free trapped garlic shoots from over-thick mulch, when 50% emerged.

Cover lettuce, spinach (“burns” below 10°F), celery, zukes & cukes and Chinese cabbage. Use double hoops for the spinach, celery, and the last lettuce bed.

Harvest: celeriac (hardy to 20°F), beets (15-20°F), turnips(20°F), kohlrabi (15°F), winter radish (20°F), rutabagas (OK to 20°F), carrots (12°F), parsnips (0°F) in that order. Wash and store in perforated plastic bags in walk-in cooler. Record yields.

After curing, store boxes of sweet potatoes in basement cage (55-60°F, 80-90% humidity).

Sort white potatoes in storage 2 weeks after harvest.

Spread lime or gypsum as needed, referring to soil analysis results.

Potato Onions: sell small ones (<1½”) or store on racks until January. Ideal conditions 32-40°F, 60-70% humidity, good ventilation, layers < 4” deep. Do not seem to suffer from freezing.

Winterize the rototillers and BCS mower.

Planning:

Week 1: Check the accounts and prepare Budget Requests for economic planning. Write Informant. Revise Seed Inventory spreadsheet.

Week 2: Inventory seeds

Week 3: Inventory seeds

Week 4: Seed Inventory: proof reading, etc. File notes.

Perennials: Cut dead asparagus tops with weed whackers or machetes, and remove all ferns. Weed strawberries and spread sawdust in aisles. Weed and fertilize rhubarb, blueberries, asparagus, and spread cardboard and sawdust, (hay for asparagus if possible). Weed grapes, take vine cuttings. Transplant new blueberries if needed.

November Harvests: last outdoor lettuce (hardy to 15°F with rowcover), beets (15-20°F), broccoli (25°F), cabbage (12°F), cauliflower, celeriac (20°F), celery (15°F with rowcover), chard (10°F), fall greens, collards (5°F), fennel (25°F), kale (0°F), kohlrabi (15°F), komatsuna (15°F), leeks (fall leeks hardy to 12-20°F, winter ones to 5°F or lower), parsnips (0°F), scallions (25°F), senposai (12°F), spinach (0°F), tatsoi (10°F), turnips (20°F), yukina savoy (10°F).

December – Time to Rest

Perennials: see November. Cut fall raspberry canes (after leaves have dropped) with pruners, to the ground. Weed raspberries. Hang blueberry drip tape in the branches. Dig docks from asparagus patch.

Plant medium potato onions, if not done in November.

Drain and store the hoses and irrigation. Clean up stakes, labels.

Planning:

Week 1: Prepare seed order spreadsheet. Decide seed order.

Week 2: Revise Lettuce List, lettuce Log. Spend last of money. Check expenditures and spend remaining budget. File the year’s accumulated notes.

Week 3: Put your feet up and read seed catalogs and inspiring gardening books

Week 4: Put your feet up and read seed catalogs and inspiring gardening books

December Harvests: cold frame spinach or lettuce, cabbage (hardy to12°F), celery (15°F with rowcover), chard (10°F), collards (5°F), kale (0°F), komatsuna, leeks (fall leeks hardy to 12-20°F, winter ones to 10°F or lower), parsnips (0°F), senposai (12°F), spinach (0°F), yukina savoy (10°F).

Winter Squash in storage at Twin Oaks potato onion planting, potato onion storage,

Winter Hardiness

It can be hard to find out just how cold a temperature various vegetable plants can survive. Reading books written in different parts of the country can be confusing: “survives all winter” is one thing in the Pacific Northwest and another in Montana. So for some years I have been collecting data and exchanging information with my friend and neighbor Ken Bezilla at Southern Exposure Seed Exchange. Each winter I try to record what dies at what temperature. Below is my current list, which should be treated as a work in progress.

Your own experience with your soils, microclimates and rain levels may lead you to use different temperatures. If you have data from your garden, please leave a comment. Likewise if you have found particular varieties to be especially cold-tolerant, I’d love to learn more. Central Virginia isn’t the coldest spot in the US, but if I can grow something without rowcover, I’m happy to hear it!

Here’s our temperature list at which various crops die:

 35°F (2°C):  Basil.

32°F (0°C):  Bush beans, cauliflower curds, corn, cowpeas, cucumbers, eggplant, limas, melons, okra, some Pak Choy, peanuts, peppers, potato vines, squash vines, sweet potato vines, tomatoes.

27°F (-3°C): Most cabbage, Sugarloaf chicory (takes only light frosts), radicchio.

 25°F (-4°C): Broccoli heads, chervil, chicory roots for chicons, and hearts, probably Chinese Napa cabbage (Blues), dill, endive (hardier than lettuce, Escarole more frost-hardy than Frisée), annual fennel, large leaves of lettuce (protected hearts and small plants will survive even colder temperatures), some mustards and oriental greens (Maruba Santoh, mizuna, most pak choy, Tokyo Bekana), onion scallions, radicchio. Also white mustard cover crop.

22°F (-6°C): Arugula, Tatsoi. (both may survive colder than this.) Possibly Chinese Napa cabbage (Blues), Maruba Santoh, Mizuna, Pak Choy, Tokyo Bekana with rowcover.

20°F (-7°C): Some beets, cabbage heads (the insides may still be good even if the outer leaves are damaged), celeriac, celtuce (stem lettuce), some corn salad, perhaps fennel, some unprotected lettuce – some OK to 16°F (-16 °C), some mustards/oriental greens (Tendergreen, Tyfon Holland greens), radishes, turnips with mulch to protect them, (Noir d’Hiver is the most cold-tolerant variety).

17°F (-8°C): Barley (cover crop)

15°F (-9.5°C): Some beets (Albina Verduna, Lutz Winterkeeper), beet leaves, broccoli leaves, young cabbage, celery (Ventura) with rowcover (some inner leaves may survive at lower than this), cilantro, endive, fava beans (Aquadulce Claudia), garlic tops may be damaged but not killed, Russian kales, kohlrabi, perhaps Komatsuna, some covered lettuce, especially small and medium-sized plants (Marvel of  Four Seasons, Rouge d’Hiver, Winter Density), curly leaf parsley, flat leaf parsley, oriental winter radish with mulch for protection (including daikon), large leaves of broad leaf sorrel, turnip leaves, winter cress.

12°F (-11°C): Some cabbage (January King, Savoy types), carrots (Danvers, Oxheart), multi-colored chard, most collards, some fava beans (not the best flavored ones), garlic tops if fairly large, most fall or summer varieties of leeks (Lincoln, King Richard), most covered lettuce (Freckles, Hyper Red Rumpled Wave, Parris Island, Tango) , large tops of potato onions, Senposai, some turnips (Purple Top).

10°F (-12°C): 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), Oriental winter radish, (including daikon), rutabagas, (if mulched), tops of shallots, large leaves of savoyed spinach (more hardy than flat leafed varieties), tatsoi, Yukina Savoy. Also oats cover crop.

5°F (-15°C): 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.

0°F (-18°C): 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). Also small-seeded cover crop fava beans.

Even Colder: Overwintering varieties of cauliflower are hardy down to -5°F (-19°C).

Many of the Even Star Ice Bred varieties are hardy down to -6°F (-20°C).

Walla Walla onions sown in late summer are hardy down to -10°F (-23°C).

Winter Field Peas and Crimson clover (used as cover crop) are hardy down to -10°F (-23°C).

Hairy vetch and white Dutch clover cover crops are hardy to -30°F (-34°C)

Sorrel and some cabbage (January King) are said to be hardy in zone 3, -30 to-40°F (-34 to -40°C)

Winter wheat and winter rye (cover crops) are hardy to -40°F (-40°C).