Tag: Asian greens

Time to Sow More Fall Brassica Crops

 

Young tatsoi plants.
Photo Bridget Aleshire

See my recent post for info about fall broccoli and cabbage. Here I provide some more information and discuss other brassicas you could grow in the fall.

Temperature and Timing for Fall Brassicas

  1. Germination: Brassica seeds will germinate at soil temperatures from 41°F (5°C) to 95°F (35°C). 41°F (5°C) can take 45 days for some brassicas, but in summer and fall, this isn’t the end of the thermometer we worry about! In summer and fall, soil temperatures are enough to germinate brassicas in 3-10 days. Optimum soil temperatures for germination are
  • 77°F (25°C) for most Asian greens, broccoli, Brussels sprouts, cauliflower, collards, kohlrabi, pak choy;
  • 86°F (30°C) for cabbage, including Napa cabbage, kale, turnips and rutabagas;
  • 68°F (20°C) for mustard greens, and perhaps arugula (which might do better even cooler)
Vates kale seedlings for bare-root transplanting outdoors.
Photo Pam Dawling
  1. Cold-Hardiness: Consult this list of winter kill (air) temperatures for brassicas, for the crops you are growing.
  • 32°F (0°C):  some cauliflower curds, some pak choy
  • 27°F (-3°C): many cabbage varieties
  • 22°F (-6°C): some varieties of arugula
  • 20°F (-7°C): 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), some cauliflower varieties, some collards (Georgia Cabbage Collards, variegated collards), some mustards/Asian greens (Tendergreen), radishes (Cherry Belle), most turnips (Noir d’Hiver is the most cold-tolerant variety).
  • 15°F (-9.5°C): some broccoli and cauliflower leaves, some cabbage (Kaitlin, Tribute), Red Russian and White Russian kales, kohlrabi, rutabagas (American Purple Top Yellow, Laurentian), most covered turnips, winter cress.
  • 12°F (-11°C): some broccoli perhaps, some Brussels sprouts, some cabbage (January King, Savoy types), most collards, Koji greens, covered rutabagas
  • 10°F (-12°C): Purple Sprouting broccoli for spring harvest, a few cabbages (Deadon), some collards (Morris Heading can survive at least one night), Belle Isle upland cress, probably Komatsuna, Chinese Thick-Stem Mustard may survive down to 6°F (-14°C), covered winter radish (Daikon, China Rose, Shunkyo Semi-Long survive), Senposai leaves (the core of the plant may survive 8°F/-13°C), Tatsoi, Yukina Savoy.
  • 5°F (-15°C): some kale (Winterbor, Westland Winter), many of the Even’ Star Ice Bred greens varieties and the Ice-Bred White Egg turnip are hardy down to 6°F (-14°C)
  • 0°F (-18°C): some collards (Blue Max, Winner, McCormack’s Green Glaze), Even’ Star Ice-Bred Smooth Leaf kale
  • -5°F (-19°C): Leaves of overwintering varieties of cauliflower, Vates kale survives although some leaves may be too damaged to use. Lacinato Rainbow Mix kale may survive this temperature.
Frosty daikon leaves.
Photo Bridget Aleshire
  1. Your Climate: Consult WeatherSpark. com to see when it begins to get too cold in your area. At our farm, the average daily low temperature on November 30 is 36°F (2°C). Decide your ideal harvest date for each crop. Although kohlrabi can take 15°F (-9.5°C), I’d want to get it all harvested by November 30.
  2. Days to Maturity: Next factor in the number of days a crop takes to reach maturity. Work back from your desired harvest date, subtracting the number of days from sowing to maturity (or from sowing to transplant, plus from transplant to maturity). Work back another two weeks for the slowing rate of growth in fall. And perhaps work back another two weeks in case in gets colder earlier than usual. This provides your sowing date.
  3. Mid-Winter Harvests: For crops that survive your winter, are you sowing to harvest in the fall, during the winter, or only in early spring? Brassicas for early spring harvest only can be sown in September or October in our climate. For those to be harvested during the winter, you need to have big enough plants going into the winter, to provide sustainable harvests (once a week in November and February and more in spring, plus maybe once a month in December and January)
Overwintered Vates kale.
Photo credit Twin Oaks Community

Various Fall Brassica Crops

In the summer we try to have a No Visible Brassicas Month to break the lifecycle of the harlequin bugs. Once our spring kale is finished, the spring cabbage gathered in, and the spring broccoli mowed down, the only brassicas are seedlings hidden under insect netting. Our hope is to starve out the harlequin bugs or at least deter them from making too many more.

We sow other fall outdoor brassicas a bit later than cabbage and broccoli. These get transplanted from our netting-covered nursery seedbeds, to our raised bed area which is more accessible for winter harvesting and more suited to small quantities.

Asian Greens

Outdoors we grow Senposai, Napa Chinese cabbage and Yukina Savoy. We have also sometimes grown tatsoi and komatsuna. Note that senposai grows quite large – give it similar spacing to collards.

We sow Asian greens for outdoors in the last week of June and first week of July, aiming to eat them before we start harvesting the ones in the hoophouse, which feed us all winter. We use Asian greens outdoors as quick-growing greens to fill the gap before our main fall greens (spinach, kale, collards, cabbage, broccoli) are ready to harvest. We don’t grow a lot outdoors.

If you don’t have a hoophouse, you can sow for outdoors later into the fall than we do, to get a longer harvest season than you otherwise would. And you certainly can direct seed them.

Yukina Savoy outdoors in December, after several nights at 16-17°F (-8 to -9°C)
Photo Kathryn Simmons

Collards

We sow collards in the first two weeks of July and transplant the bare-root transplants from the nursery bed when they are 3-4 weeks old. We plant at 18” (46 cm) in the row, with rows 12” (30 cm) apart. (if you grow a large kale, you might want similar spacing. Our Vates kale is small)

Morris Heading collards.
Photo Kathryn Simmons

Brussels sprouts

are rather a challenge in our climate, and not worthwhile. We have worked on finding the best variety (Oliver) and timing for our situation. Harvest timing is critical, as Brussels sprouts will not overwinter here.

Cauliflowers

are a tricky crop for us too. Be sure to check the “days to harvest” for each variety (they vary widely) and sow at a realistic date to get a crop before too many frosts endanger the curds. The number of days quoted for fall varieties of cauliflower already allows for the expected rate of growth at that time of year, so the 14 days for slower growth isn’t a factor. However, cauliflower is more tender, so allow for the possibility of a fall frost earlier than average.

Harvested kohlrabi, Early White Vienna and Early Purple Vienna.
Photo McCune Porter

Kohlrabi

We sow Vienna kohlrabi mid-July and transplant early August at 8” (20 cm) apart in the row, with 9-10” (23-25 cm) between rows. Later sowings (up till early September) would also work for the fast maturing varieties. Superschmelz Kohlrabi (60 days from transplanting) can also be summer sown for fall harvest. It produces 8-10” (20-25 cm) bulbs, which remain tender and an attractive globe shape.

Kale

We direct-sow two neighboring beds of kale on each of 8/4, 8/10, 8/16 and then carefully thin them, leaving one plant every 12” (30 cm). These plants grow quicker than transplants, as they have no transplant shock. Meanwhile, if we have gaps, we use the carefully dug thinnings from those beds to fill them. We want a lot of kale, and there isn’t time to transplant it all. Dividing up the sowings lets us focus on watering just one pair of beds at a time. Vates kale is the hardiest variety we have found, although I’d love to find a taller Scotch curled variety that could survive our winters (Winterbor does not survive as well as Vates).

An outdoor bed of young Vates kale Photo Kathryn Simmons

Rooty Brassicas

Radishes, rutabagas and turnips are also brassicas, but I won’t say more here. look in the further resources.

Brassica Aftercare

Brassicas started in hot conditions do not usually bolt if they have enough water.

 

Brassica seedlings under ProtekNet in August.
Photo Pam Dawling
  • Protect seedlings and the new transplants with insect netting if you have brassica leaf pests (most of do!) You can remove the netting when the transplants are well established, or leave it on.
  • Use shadecloth to keep greens cool in hot weather, or plant them in the shade of other plants.
  • To keep crops in good condition later into the winter, use rowcover. I recommend thick Typar 1.25oz rowcover, which provides 6F degrees of cold protection. I wouldn’t spend the money on anything thinner, it’s too frustrating! We do not normally use rowcover in the winter for kale and collards, as they will survive without. In harsh winters we lose the collards.

Cultivation is a simple matter of hoeing, weeding, watering as needed, and watching for pests.

Further Fall Brassica Information

Some Highlights of the PASA Conference

I enjoyed attending the in-person conference of Pasa Sustainable Agriculture. This is the first conference I’ve been to in person in two whole years. PASA did a lot to ensure the conference was as Covid-safe as possible. They limited the number of attendees (there were still plenty to ensure lots of chances to exchange information). Everyone had to test on their day of travel to the conference, and speakers had to test every day of speaking. For me that was all three days. Everyone was masked, nearly all with KN95 “real” masks. The hotel housekeeping staff only came in after we left. (We could have requested the service, but, heck, I can make my own bed!) In the workshop rooms, the chairs were spaced 6 ft apart. The trade show had wide aisles, and meals could be taken out of the dining room to a quiet spot. Just getting to be there was a big highlight for me! I left feeling energized and enthused, and very grateful to the PASA team for preparing such a successful event.

There were four sessions of workshops each day, with one-hour breaks between, allowing time to visit uncrowded trade booths, catch up with old friends, and make new ones. We were well-supplied with snacks and beverages during the breaks. There were socials with more snacks at the end of the day.

I did have trouble with the conference app, but then, my phone is limited in what it can do. Likewise I failed to upload my slideshows to the platform, so I ran them off my flashdrive. My pdf handouts did make it onto the app, so if you wanted one of my handouts, you can find it there and here:

Young Yukina Savoy plants.
Photo Ethan Hirsh
Optimize your Asian Greens Production Dawling PASA handout 2022 2.10 9am
Young spinach seedlings.
Photo Pam Dawling
Winter Vegetable Production Methods From the Field to the Hoophouse Dawling 2022 2.11 9am 6 page handout
Sweet potatoes in storage. An ideal crop for winter meals, as they store at room temperature for a long time, maybe seven or eight months.
Photo Pam Dawling
Growing Sweet Potatoes from Start to Finish Dawling 4 pg handout 2022 2.12 11am.docx

Each of the ten workshop sessions had a choice of eight or nine workshops. I had thought I might hunker down in my hotel room when I wasn’t speaking, to minimize my chance of catching Covid, but as permaculture author Darrell Frey said “This feels safer than going to the grocery store!”

I enjoyed several workshops presented by others, including:

On-Farm Experience with Organic No-Till

Sam Malriat from Rodale

No-Till sequesters carbon in the soil, but simply never tilling does not improve the soil. Chemical no-till uses lots of herbicide. Don’t be obsessive about no-till. Shallow tillage can be a responsible choice, as incorporation of organic matter is valuable. Adding cover crops, compost or manure, grazing, and a good crop rotation, can increase the OM, and thus increase the soil water capacity enormously.

Crimson clover cover crop
Photo by Bridget Aleshire

To overcome the challenges of no-till, you need a very good cover crop stand that will provide a thick mulch when terminated; a competitive cash crop; a way to plant into the residue, and a back-up plan in case one of the requirements doesn’t pan out.

Sowing corn into rolled and crimped hairy vetch does not work well, because corn is a heavy feeder and not very competitive. Better is to undersow the corn at V5 or V6 (stages of vegetative growth) with white clover or crimson clover in September. It’s important to get good seed to soil contact. The clover grows when the corn dies. This is in Rodale Country in PA. If the clover can be left growing until the second year, cabbage can be transplanted into it. His slides showed the success of this system after an unpromising start.

Pumpkins can be direct seeded in crimped and rolled (or mowed) winter rye. There is a lot of difference in thickness of the mulch between rye sown in August and October.

Organic Solutions: Pest Management

Drew Smith and Emily Gantz from Rodale

There was a big drop in pesticide use in the mid 1990’s as GMO crops came in. But then a big uptick as resistance to the GMO crops developed. Currently, almost all non-Organic seeds contain neo-nicotinoids, even though they provide no economic benefits.

Crop rotation is the single most important thing you can do to manage pests. Drew showed us the IPM triangle, and we worked our way up. To succeed in preventing pest infestations, planning of all aspects of growing the crop is vital. As is regular scouting of each crop. Cultural controls include the physical aspects of the planting. Other physical controls include mechanical aspects of growing the crop. Biological controls include encourage beneficials, releasing biological agents. Greater biodiversity provides greater stability. See Cornell Entomology https://biocontrol.entomolgy.cornell.edu/index.php

Native Pollinators: Identification, Habitat Needs and Resources

Sarah Koenig and Ryan Stauffer from the Audubon Society

A bee pollinating squash.
Photo Pam Dawling

There are 4000 species of bees in the US (20,000 globally). 70% of food crop species rely on honeybee pollination to some extent. Native bees mostly nest in the ground. Don’t kill them by compaction (or weedkillers!). Use native flowers to attract native pollinators.

Using Tarps to Reduce Tillage on Small Vegetable Farms

Ryan Maher, Cornell Small Farms & Bob Tuori, Nook and Cranny Farm

More growers are trying tarping for weed control, killing cover crops, maintaining a good soil temperature, avoiding crusting and compaction, keeping beds dry enough for planting and reducing dependence on single-use plastics. Challenges include the heavy weight, the aggravation of using sand bags, especially in windy places, ponding of rainwater runoff, and the frustration of providing perfect vole habitat.

After 28 days in summer, you gain 200 GDDs. Plant-available soil N increases by 2 or 3 times from the plant residues. How soon does it dissipate after removing the tarp? Tarping for 3 weeks after shallow tilling kills the living weeds, improves crop establishment and reduces weed emergence by up to 83%. Think of tarps as a tillage tool! Do plan for weed management after removing the tarp. Pigweed and amaranth can become worse!

We haven’t tried tarps yet. Early September photo of hay mulched June-planted potatoes.
Photo Kathryn Simmons

Bob Tuori spoke about a SARE trial of tarping in the Northeast. He compared potatoes grown with and without prior tarping, both patches with and without hay mulch after planting. The tarped area needed sandbags every 10-15 ft. The tarp was removed June 4, weeds were counted June 24, then the patches were mulched. (I hope I got that right). I did not write down all the results, but the only-mulch area grew 17.4 lbs per hour of work, and the tarp-only area grew 13 lbs per hour of work. See the SARE report for the details.

Harvesting Techniques for Small- to Mid-Scale Vegetable Farms

Julie Henninger of Good Keeper Farm and Matthew Lowe

We saw good tool and equipment storage, and learned the benefits of growing head lettuce on landscape fabric (no rotten bottom leaves, no weeds). Muir is their favorite lettuce for spring, summer and fall. At $3/head, a 95ft row planted at 9” spacing earns them $1300, if they have a 15% loss.

Beautiful baby lettuce mix in our hoophouse.
Photo Wren Vile

We learned the importance of sharp knives or scissors for cutting baby greens with minimal cell damage and browning. Theirs sells at $12/pound. They grow Salanova, which brings in $1140/bed at each cutting. If they cut whole heads, these bring in $1476 per bed.

For loose carrots, they sow rows in pairs 2” apart, with 6 rows on a 30” bed, using a stale seed bed and flaming. They sell 1000 lbs per week. Julie Henninger emphasized not wasting time by setting the carrots down in piles. Minimize the number of times each crop is touched. They have modified a cement mixer to wash 25-45 lbs at a time.

Training and communication are also very important. New workers must master the task first, before chatting. Minimize distractions. Send crews out with a strong role model each, to keep the crew working at a sustainable pace. If working with a crew with diverse abilities (eg children), provide a clear short task with a beginning and an end, to give a good sense of achievement.

I also attended the Plenary, Why Is Farming So Hard & What Can We Do About It?  on Friday with Brennan Washington, Sarah Mock and Dr Jessica Gordon Nembhard, who were livestreamed and recorded.

I participated in the book swap, setting out some spare handouts I had in exchange for a couple of magazines. I enjoyed the Farm Innovations poster display of tools and techniques to improve production or save resources (or both). I liked that previous years’ posters were available as pages in several ring binders.

In the Trade Show there were 60-odd vendors. I checked in with Nifty Hoops, a company who will deliver a hoophouse and put it up for you in one day, or help you put it up, teaching as you build. We put ours up ourselves, in 2003, and we were inexperienced and slow, and had to work on it in the (hot) afternoons, after spending the mornings farming. At events when I talk about hoophouse growing, I’ve sometimes been asked if there are companies who will erect hoophouses (high tunnels), so it’s good to be able to pass on this contact. Nifty Hoops also sell interesting components such as DC-powered inflation blowers. (734) 845-0079.  They have videos on their Facebook page

I picked up some publications from ATTRA, who have supplied me with great vegetable growing info since before the internet. (We used to call them up and ask for publications to be sent in the mail).

The Mini-Treffler manual harrow

I also was fascinated by the Mini-Treffler, from OrganicMachinery.net, a manual rolling tine harrow for crops in beds.

  • The TINY Treffler is a hand drawn harrow with the working width of 80cm (2 ft 7 in), 100 (3 ft 4 in) and 130cm (4 ft 3 in)
  • Shares the same principle with the big Treffler harrows: in the row harrowing, adjustable tension and the patented tine suspension
  • Each tine follows the contour of the field and the downward pressure remains constant
  • The TINY is effective throughout the growing season in greenhouses or for small enterprises in vegetable production or seed propagation
  • Wheels extendable from one or both sides to straddle a bed

I gathered literature for our garden crew as well as our dairy, orchard and poultry people, and an assortment of free pens, notebooks, stickers.

PASA also had a virtual conference, spread out over a couple of weeks in January. I’m sure there was great information there too, but our rural internet is not up to the task of virtual conferencing, so I’m in the dark. Pasa intends to keep a virtual conference next year as part of the mix – it works better for farmers who cannot easily leave the farm, it reduces the carbon footprint of travel, and saves on travel and hotel or BnB costs. Maybe next year I’ll have better internet. Maybe Covid will have receded. This year’s conference was great! I look forward to next year’s!

 

Winter-Kill Temperatures of Cold-Hardy Vegetables 2021

Our pond iced over.
Photo Ezra Freeman

Winter-Kill Temperatures of Cold-Hardy Vegetables 2021

I keep records of how well our crops do in the colder season, both outdoors and in our double-layer hoophouse. I note each increasingly cold minimum temperature and when the various crops die of cold, to fine-tune our planning for next year. We are in zone 7a, with an average annual minimum temperature of 0-5°F (-18°C to -15°C).

The winter 2020-2021 was mild, with our lowest temperature being a single late January night at 10°F (-12°C). We had one night at 11°F (-12°C) one at 17°F (-8°C), three at 18°F (-8°C also) and one at 19°F (-7°C). very little snow or ice. Similar to temperatures in the 2019-2020 winter.

The winter of 2018-2019 had lowest temperatures of 6°F (-14°C) in late January 2019, 8°F (-13°C) in December 2018 and a couple of 11°F (-12°C). In early January 2018, we had some extremely cold temperatures of -8°F and -9°F (-22°C and -23°C). Averaging our winter low over those four winters 2017-2021 gives 4.8°F (-15°C), within the zone 7a range.

Georgia Cabbage Collards, good down to 20F (-7C) Photo Southern Exposure Seed Exchange

New Info this winter

I’ve added in some temperatures for collard varieties (Georgia Cabbage collards, McCormack’s Green Glaze, variegated collards) from the Heirloom Collards Project, and also gained some info on spinach (Long Standing Bloomsdale), kales (Rainbow Mix Lacinato) and mustards (Chinese Thick-Stem) from Southern Exposure Seed Exchange. I’ve added in their suggestions on cold-tolerant early spring lettuces, Crawford, Simpson Elite, Susan’s Red Bibb and Swordleaf.

My results from other years still hold up.

Swordleaf lettuce on the right with another lettuce and radishes in spring.
Photo Bridget Aleshire

Using the List

Unless otherwise stated, these are killing temperatures of crops outdoors without any rowcover. All greens do a lot better with protection against cold drying winds. Note that repeated cold temperatures can kill 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. Crops get more damage when the weather switches suddenly from warm to cold. If the temperature drops 5 or more Fahrenheit degrees (about 3 C degrees) from recent temperatures, there can be cold damage. The weatherman in Raleigh, NC says it needs 3 hours at the critical temperature to do damage. Your own experience with your soils, microclimates and rain levels may lead you to use different temperatures in your crop planning.

Reflect spinach in the open got damaged but not killed at -9F.
Photo Pam Dawling

Outdoor killing temperatures of crops (unprotected unless stated)

35°F (2°C):  Basil.

32°F (0°C):  Bush beans, some 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): Many cabbage varieties, Sugarloaf chicory (takes only light frosts).

25°F (-4°C): Some cabbage, chervil, Belgian Witloof chicory roots for chicons, and hearts, Chinese Napa cabbage (Blues), dill (Fernleaf), some fava beans (Windsor), annual fennel, some mustards (Red Giant, Southern Curled) and Asian greens (Maruba Santoh, mizuna, most pak choy, Tokyo Bekana), onion scallions (some are much more hardy), radicchio, rhubarb stems and leaves.

22°F (-6°C): Some arugula (some varieties are hardier), Bright Lights chard, endive (Escarole may be a little more frost-hardy than Frisée), 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), some cauliflower varieties, celeriac, celtuce (stem lettuce), some collards (Georgia Cabbage Collards, variegated collards), some head lettuce, some mustards/Asian greens (Tendergreen, 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).

Large oat plants will get serious cold damage. Oats seedlings die at 17°F (-8°C)

Canadian (spring) field peas are hardy to 10-20°F (-12 to -7°C).

Ruby chard, good down to 15°F (-9.5°C). hardier than Bright Lights, but less hardy than green chard varieties.
Photo Kathryn Simmons

15°F (-9.5°C): Some beets (Albina Verduna, Lutz Winterkeeper), beet leaves, some broccoli and cauliflower leaves, some cabbage (Kaitlin, Tribute), covered celery (Ventura), red chard, cilantro, fava beans (Aquadulce Claudia), Red Russian and White Russian kales, kohlrabi, some lettuce, especially medium-sized plants with 4-10 leaves (Marvel of Four Seasons, Olga, Rouge d’hiver, Tango, Winter Density), curly leaf parsley, rutabagas (American Purple Top Yellow, Laurentian), broad leaf sorrel, most covered turnips, winter cress.

12°F (-11°C): Some beets (Cylindra,), some broccoli perhaps, some Brussels sprouts, some cabbage (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, some turnips (Purple Top).

10°F (-12°C): Covered beets, Purple Sprouting broccoli for spring harvest, a few cabbages (Deadon), chard (green chard is hardier than multi-colored types), some collards (Morris Heading can survive at least one night at 10°F), Belle Isle upland cress, some endive (Perfect, President), young Bronze fennel, Blue Ridge kale, probably Komatsuna, some leeks (American Flag (Broad London), Jaune du Poiteau), some covered lettuce (Pirat, Red Salad Bowl, Salad Bowl, Sylvesta, Winter Marvel), Chinese Thick-Stem Mustard may survive down to 6°F (-14°C), covered winter radish (Daikon, China Rose, Shunkyo Semi-Long survive 10°F/-12°C), Senposai leaves (the core of the plant may survive 8°F/-13°C), large leaves of savoyed spinach (more hardy than smooth-leafed varieties), Tatsoi, Yukina Savoy.

Oats cover crop of a medium size die around 10°F (-12°C). Large oat plants will die completely at 6°F (-17°C) or even milder than that.

Garlic shoots poking through the mulch in January. Survive down to 5°F (-15°C), and if killed, will regrow from underground.
Photo Pam Dawling

5°F (-15°C): Garlic tops even if small, some kale (Winterbor, Westland Winter), some leeks (Bulgarian Giant, Laura), some bulb onions, potato onions and other multiplier onions, smaller leaves of savoy spinach and broad leaf sorrel. Many of the Even’ Star Ice Bred greens varieties and the Ice-Bred White Egg turnip are hardy down to 6°F (-14°C), a few unprotected lettuces if small (Winter Marvel, Tango, North Pole, Green Forest).

0°F (-18°C): Chives, some collards (Blue Max, Winner, McCormack’s Green Glaze), corn salad (mâche), garlic, horseradish, Jerusalem artichokes, Even’ Star Ice-Bred Smooth Leaf kale, a few leeks (Alaska, Durabel, Tadorna); some bulb onions, yellow potato onions, some onion scallions, (Evergreen Winter 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): Leaves of overwintering varieties of cauliflower, Vates kale survives although some leaves may be too damaged to use. Lacinato Rainbow Mix kale may survive this temperature.

A cover crop mix of winter rye, hairy vetch and crimson clover.
Credit Kathryn Simmons

-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 cabbage 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).

Hoophouse Notes

Winter crops snug in our hoophouse in a December snowstorm.
Photo Pam Dawling

Our double-plastic hoophouse keeps night time temperatures about 8F (4.5C) degrees warmer than outdoors, sometimes 10F (5.5C) degrees warmer. Plus, plants tolerate lower temperatures inside a hoophouse. The soil stays warmer; the plants recover in the warmer daytime conditions (it seems to be the night+day average temperature that counts);

In the hoophouse (8F (4.5C) degrees warmer than outside) plants without extra rowcover can survive 14F (7.7C) degrees colder than they could survive outside; with thick rowcover (1.25oz Typar/Xavan) at least 21F (11.6C) degrees colder than outside.

For example, salad greens in our hoophouse can survive nights with outdoor lows of 14°F          (-10°C). Russian kales, lettuce, mizuna, senposai, spinach, tatsoi, turnips, 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.

Lettuce Notes

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 Rumpled Wave, 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.

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

Notes on Chicories and Endives

Verona Red radicchio, hardy to about 20°F (-7°C).
Photo Southern Exposure Seed Exchange

Chicories and endives fall into two groups, but they are confusing because the common names sometimes suggest the opposite group than they are botanically. Here’s the best info I have.

Cichorium intybus, commonly called chicories, are mostly heading crops. The group includes radicchio, both Treviso and Chioggia – hardy to about 20°F (-7°C). Belgian Witloof endive (the kind for forcing chicons) is also a chicory. It dies at 25°F (-4°C). Sugarloaf chicory is the least hardy chicory, and dies at 27°F (-3°C).

Cichorium endivia, commonly called endives, are mostly loose-leaf crops, less cold-hardy than intybus types (chicories). This group includes Frisée types and escaroles, which are also known as Batavian endives. They generally survive down to 22°F (-6°C), although Perfect and President endives can survive down to 10°F (-12°C) – can anyone confirm or deny this?

© Pam Dawling 2021

Go to my Events Page for more information on these online events

Mother Earth News Fair Online: Food Independence Course Part Two was released on 3/26/21.

It consists of eight video presentations, most of which come with pdf handouts. My contribution is Growing Asian Greens, and pairs nicely with Guide to Asian Vegetables with Wendy Kiang-Spray, author of The Chinese Kitchen Garden: Growing Techniques and Family Recipes from a Classic Cuisine. Other topics include Dandelion Wine, Homemade Teas, Food Conversations, Passive Solar Greenhouse Design, Productive Growing from Home, and Growing Your Own Spices.

You can subscribe to the All-Access Bundle for $2.99/month (or $35 for a year).

My previous contribution is an 8-part Garden Planning Course

I also did a workshop on Winter Cover Crops for Gardeners as part of the Winter Gardening Course.

All these and many more videos and handouts are available as part of the All-Access Bundle.

 

Conferences and Cover Crops

Conferences

I have had a little flurry of arranging workshops, so if you have (educational) travel plans, check out my Events page. I’ve also got two interviews lined up, for podcasts, and I’ll tell you about those when they go online.

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This coming weekend (Thursday October 31 to Sunday November 3) I will be at the Carolina Farm Stewardship Association Sustainable Agriculture Conference, Sheraton Imperial Hotel and Convention Center, Durham, North Carolina.

In the full day 8.30 am- 4.30 pm Pre-Conference intensive Advanced Organic Management, on Friday Nov 1, from 8.45-9.45 am in the Empire ballroom D, I will be presenting a 60 min workshop:

A cover crop mix of winter rye, hairy vetch and crimson clover.
Credit Kathryn Simmons

Cover Crops for Vegetable Growers

Use cover crops to feed and improve the soil, smother weeds, and prevent soil erosion. Select cover crops to make use of opportunities year round: early spring, summer, fall and going into winter. Fit cover crops into the schedule of vegetable production while maintaining a healthy crop rotation.

 In the Main Conference, on Sat Nov 2, 1.30 – 2.45 pm in the Empire Ballroom E, I have a 75 min workshop

Yukina Savoy
Photo Wren Vile

Optimize your Asian Greens Production

This workshop covers the production of Asian greens outdoors and in hoop houses in detail, for both market and home growers. Grow many varieties of tasty, nutritious greens easily and quickly, and bring fast returns. The workshop includes tips on variety selection of over twenty types of Asian greens; timing of plantings including succession planting when appropriate; crop rotation in the hoop house; pest and disease management; fertility; weed management and harvesting.

 I will be participating in the Booksigning on Saturday 5.45 – 6.45 pm during the reception

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Crimson clover is a beautiful and useful cover crop.
Photo Kathryn Simmons

Winter Cover Crops

 

Cover crops have been much on my mind. Partly it’s that time of year – too late for us to sow oats, not so late that the only option left is winter rye. Here’s my handy-dandy visual aid for central Virginia and other areas of cold-hardiness zone 7a with similar climates.

If you are considering growing winter rye as a no-till cover crop this winter, check out this video:

Rye Termination Timing: When to Successfully Crimp, by Mark Dempsey

“Interested in no-till production, but unsure of how to manage cover crops so they don’t become a problem for the crop that follows?

The most common management concern is when to crimp your cover crop to get a good kill but prevent it from setting seed. Getting the timing right on crimping small grain cover crops like rye isn’t difficult, but it does take a little attention to its growth stage. See this three-minute video for a quick run-down on which stages to look for in order to get that timing right.”

https://www.youtube.com/watch?v=loKPRLdAUXw

 

Sustainable Market Farming on sale.
Photo Ken Bezilla

A good cover crop resource is my book Sustainable Market Farming, which has 9 pages of detailed charts and a nine page chapter of cover crop info.

 

 

Managing Cover Crops Profitably from  SARE is the book with the most information.

Back-up plans for winter hoophouse crops

Lettuce “filler” transplants to fill gaps.
Photo Pam Dawling

Because crops grow slowly in cold weather, if something goes wrong at the beginning of the winter, or in the fall, the consequences can cast a long shadow. It is not easy to make up for lost time. In spring, the weather is getting warmer, the daylight is lengthening, and you may have noticed that later sowings can catch up with ones a week or two earlier, allowing for a second chance. In the fall, the rate of growth is moving in the opposite direction, and later sowings will stand no chance of catching up. Even worse, they may get “trapped” like Persephone in the Underworld during the dark Persephone Days. But don’t despair – there are things you can do ahead of time to be prepared for plans going awry, and there are even a few things you can do instead of your original plan, to ensure you get some crops to harvest.

Transplant seedlings under insect netting outdoors.
Photo Pam Dawling

Starting outdoors in September

We sow a lot of our winter crops outdoors in September, and transplant them into the hoophouse in October. This gives us an extra few weeks to prepare the hoophouse beds, and gives the seeds the cooler outdoor conditions to germinate in. We have three sowing dates.

On September 15, we sow 10 varieties of hardy leaf lettuce and romaines; pak choy, Chinese cabbage, Yukina Savoy, Tokyo Bekana, Maruba Santoh and chard

On September 24, we sow another 10 varieties of lettuce; Red and White Russian kales, Senposai, more Yukina Savoy, mizuna and arugula, and we resow anything that didn’t do well in the 9/15 sowing

On September 30, we resow anything that didn’t do well in the 9/24 sowing, or substitutes.

Emergency back-up seedlings for the hoophouse.
Photo Pam Dawling

This year, we had poor germination of a lot of the 9/15 sowings and too many of the 9/24 sowings. As a back-up for the back-up plans we sowed some crops in Winstrip trays, and spotted lettuce in open flats, which we kept inside the hoophouse. By that point, conditions in the hoophouse were more crop-friendly than outdoors. We did need some of these, and the rest we harvested for salad mixes right out of the flats! We were short of salad items because of the late establishment of the plants, so every plant was a help!

A flat of lettuce transplants in the path in the hoophouse.
Photo Pam Dawling

Our goal is to keep the space filled with useful crops.

Success with this goal relies on a cluster of strategies

  1. The fall transplant program I describe above.
  2. Follow-on crops: A sequence of different crops occupying the same space over time. It’s important to know when crops will bolt, and how to plant sensible quantities
  3. Filler crops: As well as scheduled plantings, in October we sow a few short rows of spinach, lettuce, Senposai, Yukina Savoy, Maruba Santoh, Tokyo Bekana to transplant into gaps as soon as they occur. We simply dig them up, replant where needed and water well. Bare-root transplants are much easier than many fear. They save time and money, compared to growing starts in flats, and save on greenhouse space. They are very sturdy plants, as they have the full depth of soil to develop big roots. Little extra care is needed, as they are less prone to drying out than seedlings in flats. Alternatively you could keep some plug flats of these plants handy. We fill gaps with Asian greens, spinach or lettuces as appropriate, until Jan 25. From Jan 25 to Feb 20 we fill all gaps everywhere with spinach From Feb 20, we only fill gaps on the outer thirds of the beds, leaving centers free for tomatoes, etc.

    Filler brassica transplants in our hoophouse in November.
    Photo Pam Dawling
  4. Interplanting: After 2/20, we harvest the winter crops from the center rows first, plant the new early summer crops down the center, then harvest the outer rows bit by bit as the new crop needs the space or the light. This overlap allows the new crops to take over gradually. Our winter and spring crops end in April
  5. Fast Catch Crops. Some cool-weather crops mature in 60 days or less. Mostly these are greens and fast-growing root crops. Useful if a crop fails, or you have a small empty space. Details on some of these follow the list.
  • Ready in 30–35 days in fall, longer in winter: arugula, many Asian greens (Chinese Napa cabbage, Komatsuna, Maruba Santoh, mizuna, pak choy,.Senposai, tatsoi, Tokyo Bekana and Yukina Savoy), brassica salad mixes, chard, kale, radishes, salad greens (lettuce, endives, chicories) spinach and winter purslane. Peashoots in late winter or spring.
  • Ready in 35–45 days in fall: chervil, corn salad, land cress, parsley and sorrel.
  • Ready in 60 days in fall: beets, small fast cabbage, collards, kohlrabi and turnips.

 Asian Greens

Asian greens are better able to germinate in hot weather than lettuce, and are faster growing than lettuce. Transplant 2-3 weeks after fall sowing, or direct sow.

Asian greens are nutritious as well as tasty – flavors vary from mild to peppery – read the catalog descriptions before growing lots. Colors cover the spectrum: chartreuse, bright green, dark green and purple. A diversity of crops without a diversity of growing methods!

Brassica (Mustard) Salad Mixes

Interesting mustard mixes are sold for salad mixes. We often mix our own Brassica Salad Mix from leftover random brassica seeds. For a single cut, almost all brassicas are suitable – just avoid turnips and radishes with prickly leaves! We sow between 10/2 and 11/14 for winter harvest and from 12/4 to 2/12 for March and early April harvests. We’re zone 7, central Virginia.

Chard and Beet Greens

Green chard is hardier than the multi-colored Bright Lights. Days to maturity: 61 – 103 days, a big difference, depending when you sow. Sow 9/15, harvest 11/15 – 5/10; Sow 10/26, harvest 2/6 – 5/10.

Radishes in our hoophouse in February.
Photo Pam Dawling

Radishes

Varieties we like: Easter Egg, White Icicle, and Cherry Belle.  Sparkler got too fibrous for us, as did Cherry Belle after mid Oct. We make 6 sowings 9/6 – 1/26. Small radishes take 27–52 days to maturity, not counting days too cold to grow.

Scallions in our hoophouse in late November.
Photo Pam Dawling

Scallions

We sow 9/6 for harvest 12/1 – 3/1; 11/18 (following radishes) for harvest in early spring. This winter we are trying a sowing 10/20 also (we happened to have a space at that time, in a spot where it fitted our rotation). Evergreen Hardy White and White Lisbon scallions are hardy down to 0°F (-18°C)

Spinach

We loved Tyee and now grow Escalade, Reflect, Acadia and smooth leaf Renegade. Renegade makes good Nov/Dec growth; Acadia, Escalade yield well Jan – April; January sown Reflect does well.

  1. Succession Planting for Winter Hoophouse Crops

We do 2 sowings of chard, scallions, tatsoi and yukina savoy; 3 sowings of  mizuna, turnips and bulb onions; 4 sowings of baby lettuce mix and brassica salad mix; 5 sowings of spinach and radish. Our goal is to provide a continuous supply.

As temperatures and day-length decrease in the fall, the time to maturity lengthens – a day late in sowing can lead to a week’s delay in harvesting. As temperatures and day-length increase after the Winter Solstice, the time to maturity shortens – later sowings can almost catch up with earlier ones. To get harvests starting an equal number of days apart, vary the interval between one sowing date and the next accordingly. Here’s the most dependable method:

Making a Close-Fit Plan Using Graphs

  1. Gather sowing and harvest start and finish dates for each planting of each crop you are growing as successions.
  2. Make a graph for each crop: sowing date along the horizontal (x) axis; harvest start date along the vertical (y) axis. Mark in all your data. Join with a line. Smooth the line.
  3. From your first possible sowing date find the first harvest start date.
  4. Decide the last worthwhile harvest start date, mark that.
  5. Divide the harvest period into a whole number of equal segments, according to how often you want a new patch.
  6. Mark in the harvest start dates and see the sowing dates that match those harvest dates
Overgrown hoophouse filler greens in our hoophouse in December.
Photo Wren Vile

Working around the Persephone Days

In Indiana (in Zone 5b) Ben Hartman (The Lean Farm) sows salad greens & spinach for winter harvests every week Sept 15–Oct 15. Baby lettuce sown before Oct 22 takes 5–6 weeks until harvest. If sown Oct 24–Nov 16, it takes 8–17 weeks to harvest. In Zone 5b, if you want baby lettuce mix before December, sow before Oct 22.

Spinach sown before Oct 11 takes 4–6 weeks to harvest. If sown from Oct 20–Nov 1, it takes 12–15 weeks. To harvest spinach before December, he sows before the middle of October.

For new year harvests he sows every week Oct 15–Nov 1. He then takes a two month break from planting (Nov-Dec). Jan 1–Jan 15 he sows both salad greens and spinach for late winter.

In Zone 7 we can harvest outdoor lettuce and spinach in December, and we have less urgency about early hoophouse sowings (and we get no winter break!).

 

 

 

 

Young greens in the hoophouse, nematodes, upcoming events

Young senposai transplant in our hoophouse.
Photo Pam Dawling

After the set-backs with our winter hoophouse greens  transplants that I wrote about last week, we worked really hard and got the whole house planted up. Most of the transplants have recovered from their transplant shock (wilting each day), during the cloudy weather we had.

The new seedlings are coming up fast and calling on us to thin them. We ended up not needing so many of the Plan D plug flat plants, but we’ve kept them for now “in case” .

Young Tokyo bekana transplant in our hoophouse .
Photo Pam Dawling

Ultimately if we don’t need them, they’ll go in a salad mix. I wrote about making salad mix last year. The past two days I have been able to harvest a mix in the hoophouse. The ingredient we are shortest of is lettuce. My first mix was spinach, Bulls Blood beet leaves, a few leaves of Tokyo Bekana, Bright Lights chard, Scarlet Frills, Ruby Streaks and Golden Frills, and a handful of lettuce leaves. Red Tinged Winter is growing fastest, of all the varieties we planted this year.

Ruby Streaks transplant in our hoophouse. Compare with Scarlet Frills below.
Photo Pam Dawling
Golden Frills mustard transplant in our hoophouse. I harvested a leaf for salad mix yesterday.
Photo Pam Dawling
Scarlet frills mustard in our hoophouse. Notice that this crop is frillier than Ruby Streaks.
Photo Pam Dawling

The mix I made today had fewer ingredients. I left the frilly mustards, the lettuces and the Tokyo bekana alone to grow some more. I used Bulls Blood beets, spinach, tatsoi outer leaves and a few Bright Lights chard leaves and stems.

Cucumber roots with nematodes (see circles).
Photo Pam Dawling

I have a new Mother Earth News blogpost, about the nematodes in our hoophouse. And I’m preparing a new slide show for the Carolina Farm Stewardship Association conference. See my Events page for details

For those of you on other social media, here are their handles and links (use the hashtag #CFSAC2018).

This week we will be popping garlic for planting and having our Annual Garden Crop Review meeting. Next week I’ll tell you more about garlic planting as part of the Alliums for November post.

Popping garlic cloves in preparation for planting
Photo credit Southern Exposure Seed Exchange

Asian Greens for April: Mizuna and ferny mustards

Green mizuna in its prime in our hoophouse in November. Photo Pam Dawling

In April, sadly, our last mizuna and ferny mustards will come to an end. In our hoophouse we do three plantings of these frilly leaved greens, which we use for salads all winter and early spring.

Mizuna (also known as kyona  and shui cai) is a Brassica rapa var. japonica, meaning it’s in the turnip family. The other frilly mustards, such as Ruby Streaks, Golden Frills, Red Rain are Chinese Mustards, B. juncea. We tend to treat them as if they are all types of mizuna. True mizuna is available in green or purple (but Ruby Streaks and Scarlet Frills mustards are much better colors than Purple Mizuna.)

Golden Frills and Ruby Streaks in our hoophouse in February.
Photo Pam Dawling

All are very easy to grow, can be transplanted or direct-sown, and tolerate cold wet soil. They are ready to be harvested for baby salads only 21 days after sowing in the fall (longer in winter). They grow to maturity in 40 days. They are easy-going vegetables, fairly heat tolerant (well, warm tolerant) and cold-tolerant to 25°F (-4°C).  All regrow vigorously after cutting. The ferny leaves add color and loft in salad mixes, as well as an attractive leaf shape.

Mizuna is very mild-flavored. The ferny mustards vary in pungency, but most only become markedly spicy when they start bolting.

Like all Asian greens, they need similar care to other brassicas, doing best in very fertile soils. They are shallow-rooted – pay extra attention to providing enough water during hot weather to prevent bitter flavors and excess pungency, especially with the B. juncea ones. Provide 1” (2.5 cm) of water per week, 2” (5 cm) during very hot weather.

Do close monitoring of pests, which can build up large populations during the summer. Growing these over the winter, as we do, we have not had many pest problems. Flea beetles sometimes, once the weather starts to warm.

Young Ruby Streaks (our second planting) in our hoophouse in early February. We thin for salads until the plants are at final spacing.
Photo Pam Dawling

Our mizuna schedule

On September 24 we sow these little crops in our outdoor nursery seedbed, which is covered with insect netting on hoops. We sow 7.5′, with roughly equal amounts of Green Mizuna, Golden Frills, and Ruby Streaks or Scarlet Frills. Red Rain is another we like. We are aiming for about 75 transplants on October 20. We transplant them 8″ apart with 6 rows in a 4′ bed. This takes 8′ length of a bed. This first planting will feed us from November 27 to January 25, with light harvests possible from November 5, and flowers and sprouting shoots as late as February 10.

Our second planting is direct sown in the hoophouse on November 9. We sow 6 rows about 6′ long (depending on available space). We thin these into salad mixes several times as they grow, increasing the spacing until they are about 6-10″ apart. After that we harvest by cutting off the larger leaves, sometimes individually, sometimes by “buzz-cutting” (snipping off leaves on one half of the plant an inch (25 mm) above the ground). Leaving half of the leaves growing seems to help the new leaves grow faster. Next time we harvest, we cut the other side. This planting provides harvests from February 26 to March 24 – just one month, although we get the thinnings from January 20, and the flowers and bolting shoots until mid-April.

Our third planting, green mizuna and Scarlet Frills, in our hoophouse in mid April. The mizuna is bolting, but the Scarlet Frills is hanging in there.
Photo Pam Dawling

A couple of years ago we added in a third planting, because we had some open space in the hoophouse. It follows the first Yukina Savoy. I wrote about some differences between the OP Yukina Savoy and the hybrid Koji. Perhaps Koji is less bolt-resistant than the OP. Late January brings it to an end.

We sow this third planting on February 1 and harvest it for a month from March 24 to April 23. This year this third planting is bolting April 15. (We have had a lot of temperature reversals this spring, which encourage bolting in brassicas.) Scarlet Frills and Golden Frills bolt later than Ruby Streaks and Green Mizuna. The timing of harvest fits perfectly with the second planting. We have sown it as late as March 3 and harvested April 10-April 30 (only 3 weeks when we sow that late).

Seed sources

Kitazawa Seeds sell 18 baby leaf mustards, including four red, purple or streaked mizunas. The other 14 are B. juncea, although a few don’t say. Most are frilly or ferny, a few merely wavy. Something for everyone.

Johnnys lists their selection under “Greens” along with arugula, large Asian greens, mixes. I counted about 15 mustards that fit the loose category I’m talking about here.

Fedco lists theirs under “Asian greens”. Scroll down past Mizuna to Mustards to find several interesting gene pool offerings such as Pink Lettucy Mustard (Variations of greens with pink or purple pigments in midribs) for those seeking milder flavors; and the medium hot Purple Rapa Mix Gene Pool (sold out as I write this): Very vigorous tall serrated green leaves with purple veins and shading.

Bye bye mizuna! Bolting mizuna (our third planting) in our hoophouse in mid-April.
Photo Pam Dawling

This is my twelfth and last Asian Greens of the Month series. You can see the others here:

May Senposai outdoors

June Tokyo Bekana

July Maruba Santoh

August Fall Senposai, winter Yukina Savoy

September Komatsuna outdoors

October Yukina Savoy outdoors, Tatsoi

November Daikon and other winter radish

December Pak Choy

January Chinese cabbage

February Tatsoi

March Yukina savoy in the hoophouse

Next month I’ll start another year-long series Allium of the Month

Asian Greens for March: Yukina Savoy in the Hoophouse

Koji Yukina Savoy in late December.
Photo Pam Dawling

I wrote about outdoor Yukina Savoy going into the winter, in my October post. Re-read that to get details of days to maturity, cold-tolerance (10F/-12C outdoors) and the differences between the open-pollinated Yukina Savoy and hybrids such as Koji. Five months after that posting we are harvesting the last of the over-wintered Yukina Savoy in the hoophouse. For us, this is a cooking green, not a salad crop. It’s delicious and easy to cook. A little robust for salads, for most people.

Young Yukina Savoy plants in our hooophouse.
Photo Wren Vile

In March we are starting our hoophouse crop transition to early summer crops (tomatoes, peppers, squash, cucumbers) and meanwhile we are enjoying harvests of arugula, brassica salad mix, Bulls Blood beet greens, chard for salad and cooking greens, Russian kales, leaf lettuce, lettuce heads, baby lettuce mix, mizuna and frilly mustards, radishes, scallions, senposai, spinach, tatsoi, turnips and greens and yukina savoy.

We do two hoophouse plantings of Yukina Savoy: the first transplanted from outdoors on October 6, feeds us from December 5 to January 31. The second, transplanted from outdoors on October 24, feeds us from January 8 to early March, sometimes to mid-March. This spring several crops are bolting earlier than hoped-for! We have had some back-and-forth temperatures, which can trigger bolting. Among brassicas, Yukina Savoy is relatively heat-tolerant. This is part of why we do the second planting – it helps us extend the brassica season until we can harvest more outdoor kale.

We transplant Yukina Savoy at 12″ (30 cm) apart in the row, with 4 rows to a 4′ (1.2 m) bed. For a hundred people with lots of other vegetables available, we plant 60 in the first planting and 40 in the second. There are too many other crops competing for space in late October for us to plant more than 40.

Harvesting Yukina Savoy leaves in late November.
Photo Wren Vile.

Initially we harvest this crop by the leaf, until we see the stems start to elongate prior to bolting, when we cut the whole plant. (It is a loose head type of crop, so don’t wait for a firm head to form!)  Actually we pull first, then cut off the head, then bang two roots together to shed the soil, and put the pulled root stumps on the bed to dry out and die. This is easier than cutting first and pulling later. If they do bolt before we get round to pulling them, I have added the pretty yellow flowers to the salad mix. Like all other brassica flowers, these are edible.

Kitazawa Seeds tells us that Yukina Savoy is a Brassica rapa Pekinensis group, for those with a love of brassica botany and those saving seeds. Also those, like us, looking for nematode-resistant vegetables. Brassica juncea are the most resistant brassicas. Kitazawa classifies it as a loose head type of Chinese cabbage.

Yukina Savoy in the early morning mist.
Photo Wren Vile

Asian Green for February: Tatsoi

A large tatsoi plant in our hoophouse in December. Photo Kathleen Slattery

Tatsoi is a very cold-hardy green (down to 10°F, –12°C), one of the ones we grow in our hoophouse to feed us after the winter solstice, when the crops have started to be fewer in number and each is less abundant in production rate.  We have also grown this one outdoors in the fall for early winter eating, but no longer do this as the rate of growth inside the hoophouse is much better. In the fall tatsoi will not bolt, but in late winter/early spring it will.

I have been writing about a particular Asian green once a month since last May. To find the other articles, click the category “Asian Greens”.

Like Asian greens in general, tatsoi is a great crop for filling out winter CSA bags or market booths, and ultimately, dinner tables. Because the Asian greens are so varied in color, texture, shape and spiciness, you can add a lot of diversity to your crops by growing a selection that is easy to grow and can all be treated the same way. They are as easy to grow as kale. They germinate at a wide range of temperatures and make fast growth (much faster than lettuce in cold weather!)

Botanically, tatsoi is Brassica rapa var. narinosa, cousin of other turnip family greens such as Chinese cabbage, Tokyo Bekana, pak choy, mizuna and komatsuna. It is a more distant cousin of the Brassica oleracea greens such as Vates kale, Chinese kale and kai-lan, and of crops in the Chinese Mustard family, Brassica juncea (the frilly mustards like Ruby Streaks and Golden Frills).

Tatsoi is a relatively small plant with shiny, dark green spoon-shaped leaves and green-white stems. If given plenty of space it grows as a flat rosette, but if crowded it takes on a flowerpot shape. For sale, the whole plants are cut and the leaves banded together, so crowding them does not at all make them less marketable. It has a pleasant mild flavor.

Young tatsoi plants in our hoophouse.
Photo Bridget Aleshire

Growing Tatsoi

We direct sow and then thin into salad mixes, leaving some to mature at 10″ (25 cm) across for cooking greens.  You can also transplant at 3-4 weeks of age in the fall, at 6″ (15 cm) apart. Although we transplant most of our brassicas, to allow the beds more time without this crop family (which we grow lots of), we direct sow this one, which will have many plants in a small space.

Tatsoi has similar care requirements to other brassicas. Very fertile soils grow the best Asian greens, so turn in leguminous cover crops or compost to provide adequate nutrition. Asian greens are shallow rooted – Pay extra attention to providing enough water to prevent bitter flavors and excess pungency. Expect to provide 1” (2.5 cm) of water per week in cooler weather, 2” (5 cm) during very hot weather.

Do close monitoring for pests, which can build up large populations during late summer. We do nothing special for our tatsoi, but if you have a lot of brassica flea beetles or uncontrolled caterpillars, cover the sowings or new transplants with insect netting such as ProtekNet.

If you are growing tatsoi outdoors in late fall, you could use rowcover to keep your plants alive longer into the winter.

For our hoophouse, we make a first sowing of tatsoi in the very first bed we prepare for winter crops, on 9/6. We make a second sowing in mid-November. The first sowing will feed us for two months, November and December.  The second sowing will feed us for a much shorter period of time: the second half of February, first week of March. It would bolt if we tried to keep it any longer.

It is entirely possible to make sowings between 9/6 and 11/15, and get harvests that last longer than our 11/15 sowing. The only reason we don’t is that we have so many other crops we love.

Kitazawa Seeds have a Red Violet tatsoi/pak choy hybrid, with an upright habit. They classify tatsoi as a type of pak choy/bok choy/pak choi, so if you are perusing their interesting site, this is how to find tatsoi.

Tatsoi ready for harvesting of whole plants.
Photo Pam Dawling

Harvesting Tatsoi

Tatsoi takes 21 days to be big enough for baby salads; 45 days for cooking size.

To harvest, initially we thin the rows to 1″ (2.5 cm), using baby plants in salad mix. Our first sowing provides thinnings from 10/8, one month after sowing. Next we thin to 3″ (7.5 cm), using these also for salad. Our next thinning, to 6″ (15 cm) gives us small plants for cooking. After this, we harvest individual leaves for salad or cooking. The second sowing provides thinnings 12/27-1/21 approximately.

Once we get close to the time the plants would bolt, we pull up whole plants and use them for cooking. We pull the most crowded plants first, giving the others time to grow bigger – they can grow as big as 12″ (30 cm) across. Overcrowding can lead to early bolting.

Overview of Winter Hoophouse Greens

In the big scheme of things, we harvest Tokyo Bekana and Maruba Santoh for heads in December, along with our first tatsoi; our first Yukina Savoy, our Chinese cabbage and Pak Choy in January, our second tatsoi and Yukina Savoy in February and early March.

Non-heading leafy greens such as Senposai, spinach and chard feed us all winter until mid-March when we need the hoophouse space for spring crops. (Read more about Yukina Savoy here in March.)

After Tatsoi

We clear our first tatsoi by 1/14, and use the space to sow our fifth spinach on 1/15. This planting of spinach is to be used as bare root transplants outdoors in March. Our second tatsoi is cleared 3/12 to prepare the space for early summer crops like tomatoes, peppers, beans, squash and cucumbers.

Beauty in a tatsoi plant.
Photo Wren Vile

Asian Greens for January: Chinese Cabbage

Sorry for the delay this week – technical problems.

Young Chinese cabbage transplants in our hoophouse in October. Photo by Bridget Aleshire

If you have Chinese cabbage in your hoophouse, January is the month to harvest it in zone 7. We do not harvest leaves from this crop, but wait for it to form full-size heads and then harvest those mature plants. We sometimes start harvesting as early as December 4, if the plants have reached full size and we “need” to harvest them. Otherwise we wait till December 15. If we have planted enough we can harvest until January 23, or sometimes as late as February 9.

Other Asian greens we are also harvesting at this time of year include pak choy, mizuna and the frilly mustards, tatsoi, Senposai, Tokyo Bekana, Maruba Santoh and Yukina savoy.

Chinese cabbage has very tender, light green savoyed leaves and is excellent for stir-fries, or pickling (sauerkraut or kimchee).

Chinese cabbage (both the Napa kind and the Michihli or Michihili kind) are Wong Bok types (Brassica rapa var. pekinensis) along with the “celery cabbages” – the non-heading Tokyo Bekana and Maruba Santoh.

We like Blues, an open-pollinated “barrel-shaped” Napa cabbage, shown in the photo above. Kasumi has the best bolt tolerance and is larger: 5 lb (2.3 kg) compared to 4 lb (1.8 kg); Orange Queen is a colorful but slower-growing variety (80 days in spring).

Napa and Michihili Chinese cabbages in October.
Photo Wren Vile

The Michihili types are taller and narrower, can be transplanted closer (8″) and might make more sense in terms of space use, although Napa cabbages do store better under refrigeration than michihli types. Jade Pagoda and the O-P Michihli both take 72 days from sowing to harvest in spring – considerably slower than Napa types. Michihili are more stress tolerant and resistant to bolting and black speck than Napa cabbage.

Blues takes 52 days from sowing to harvest in spring, but of course, takes longer in fall and winter. We sow September 15 in an outdoor nursery seedbed, and transplant into our hoophouse at 2-3 weeks old (October 2). It is very fast-growing in those temperatures and conditions. If we start harvesting December 15, it’s 3 calendar months from sowing, 91 days. The minimum germination soil temperature for Chinese cabbage is 50F (10C), and the ideal soil temperatures are 68F (20C) to 86F (30C). Under the ideal conditions the seedlings will emerge in 4 days. The maximum soil temperature to get any germination is 95F (35C).

We plant 52  plants for 100 people, with 4 staggered rows in the 4ft bed, 10.5″ apart (every 7th tine on Johnny’s row marker rake) and plants 10″ apart. With a harvest period of 5-8 weeks, 6-10 heads per week is about right for us.

We have not had many disease or pest problems with our hoophouse Chines cabbage. We do pay attention to using insect netting over the outdoor seedbed in the fall, but once we transplant indoors, our pest troubles are usually over. Vegetable weevil larvae have caused trouble in January. They come out of the soil at night and make holes in the leaves. They tend to prefer pak choy and turnips. We have used Spinosad against them with some success.

Chinese cabbage.
Photo Ethan Hirsh

Tipburn (brown leaf margins, including internal leaves) is caused by quick drying of the soil, when the weather makes a sudden switch to bright and sunny from overcast. Be ready to irrigate when the weather suddenly brightens.

The winter-kill temperature of Chinese cabbage outdoors without protection is 25F (-4C). Our hoophouse crop has taken outdoor temps of 8F without inner rowcovers, and -8F with added thick rowcover. It is more cold-hardy than most varieties of pak choy, and less cold-hardy than Komatsuna, Senposai, tatsoi, Yukina savoy. Mizuna, Maruba Santoh and Tokyo Bekana have a similar level of cold-tolerance.

Once past the winter solstice, the order of bolting of Asian greens is something like: Tokyo Bekana and Maruba Santoh, pak choy, Chinese cabbage, tatsoi, Komatsuna, Senposai, mizuna, Yukina Savoy, leaf radish, frilly mustards.

When it’s time to harvest, we lever and pull the plant out of the soil, then cut off the root. This helps with the next task of replanting the space. It is much easier than cutting the plants at the base and then digging up the root.

After the Chinese cabbage are all cleared, we might follow with kale or collards on January 24 to transplant outdoors as bare root transplants in March. If we have no plans for a follow-on crop that early in the year, we fill gaps in the Chinese cabbage plot until January 25, using “filler” Asian greens we sowed in October. After that date we fill all gaps with spinach transplants until February 20, and from then on we only fill gaps on the edges of beds, leaving the bed centers free for tomatoes, etc in mid-March.

Close-up of Chinese cabbage in our hoophouse in late November. Photo Pam Dawling

Resources

  • Grow Your Own Chinese Vegetables, Geri Harrington, 1984, Garden Way Publishing. Includes the names for these crops in different cultures.
  • Growing Unusual Vegetables, Simon Hickmott, 2006, Eco-Logic books, UK.
  • Oriental Vegetables: The Complete Guide for the Garden and Kitchen, Joy Larkham, revised edition 2008, Kodansha, USA
  • The Chinese Kitchen Garden: Growing Techniques and Family Recipes from a Classic Cuisine, Wendy Kiang-Spray