Detailed information for market and home growers. Many varieties of tasty, nutritious greens grow quickly and bring fast returns. This session covers production of Asian greens outdoors and in the hoophouse. It includes tips on variety selection of over twenty types of Asian greens; timing of plantings; pest and disease management; crop requirements and harvesting.

1. Producing Asian Greens
©Pam Dawling 2017
Twin Oaks Community, Central Virginia
Author of Sustainable Market Farming
Published by New Society Publishers
SustainableMarketFarming.com
facebook.com/SustainableMarketFarming

2. Outline
1. Meet the Asian Greens
2. Crops I recommend for easy success
3. Crops to try later
4. Crop requirements
5. Pests and diseases
6. Growing in spring
7. Growing outdoors in fall
8. Growing in the winter hoophouse
9. Harvesting
10.Minimizing nitrate accumulation in winter
11.Seed saving
• Pak Choy. Credit Ethan Hirsh

3. 1. Meet the Asian Greens!
• Huge range of attractive varieties
• Quick-growing, bring fast returns
• Grow when you normally
grow cabbage or kale
• Short spring season, bolt
when it gets hot
• Long fall season, no bolting.
Success depends on getting
them germinated and planted in
June and July
• Grow all winter in hoophouses in
central Virginia
Blues Napa Chinese cabbage
shown here
Credit Ethan Hirsh

4. Advantages
 A quick way to fill out your
market booth or CSA bags
 A catch crop for spaces where
other crops have failed or
otherwise finished early. Keep
a flat of seedlings ready, pop
plugs into any empty spaces
 Better able to germinate in
hot weather than lettuce
 Faster growing than lettuce
 Faster-growing types are
ready for transplanting 2
weeks after sowing (or you
can direct sow)
 Trial many kinds, use
unwanted seed in baby salad
mix!
Our hoophouse in November
Photo Ethan Hirsh

5. Healthful Diversity!
 Flavors vary from mild to
peppery - read catalog
descriptions before growing
lots
 Colors cover the spectrum:
chartreuse, bright green, dark
green and purple
 Nutritious as well as tasty
 High in carotenoids, vitamins A
and C, calcium, iron,
magnesium and fiber
 Help prevent high blood
pressure, heart disease, stroke
 They contain antioxidants
which fight against cancer and
protect eyes from macular
degeneration
Photo Credit Ethan Hirsh

6. Who’s Who – 3 main groups
1) The turnip family, Brassica rapa,
of Asian origin
a. Some crops are Brassica rapa var.
pekinensis (napa cabbage,
michihli, celery cabbage);
b. Others are B. rapa var. chinensis
(bok choy),
c. B. rapa var. japonica (mizuna),
d. B. rapa var. narinosa (tatsoi),
e. B. rapa var. perviridis (komatsuna)
Different sources use different names
2) The cabbage family, B.
oleracea, of European origin
Kai-lan, Chinese kale
3) The Chinese Mustard family,
B. juncea
Ruby Streaks (shown here, Photo
Johnnys Seeds),
Golden Frill, Red Rain
If you plan to grow seed of more
than one Asian green, carefully
choose ones that won’t cross. Be
aware of the possibility of brassica
crops being wrongly classified

7. 2. Crops I recommend
1a. Brassica rapa var. pekinensis
Wong Bok types
• Napa cabbage is a Che-foo type
of wong bok,
• Cylindrical cabbages such as
Michihli (below) and Jade
Pagoda are Chihli types of wong
bok
• Photo Southern Exposure Seed Exchange
Celery cabbage types
• Loose-leaf, non-heading, fast-
growing vegetables with light
green leaves and white petioles.
Maruba Santoh and Tokyo
Bekana (below)
• Photo Johnnys Seeds

8. 1a. Brassica rapa var. pekinensis.
Napa cabbage
Photo Kashruth Council of Canada
• A type of wong bok
• Very tender, light green leaves
• Excellent for stir-fries, pickling
• Hardy to about 25°F (–4°C)
• We like Blues (52 days from
seed to harvest) best
• 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)
• All are hardy to about 25°F
(–4°C)
• Stores better than michihli types

9. 1a. Brassica rapa var. pekinensis
Michihli (Cylindrical Wong Bok)
Chinese cabbage
• Produces 16" (40-cm) tall heads
6" (15 cm) across.
• Produces more in the same
space compared to Napa
cabbage
• Very tender, light green leaves
• Excellent for stir-fries and
pickling.
• More stress tolerant and
resistant to bolting and black
speck than Napa cabbage
• Cannot be stored as long.
• We like Jade Pagoda (72 days)
and the O-P Michihli (72 days)
• Photo Southern Exposure Seed Exchange

10. 1a Brassica rapa var. pekinensis
Celery cabbage (pe tsai)
Photo credit Johnnys Seeds
The second type of B. rapa:
• A fast-growing, looseleaf,
non-heading vegetable with
light green leaves and white
petioles.
• Mild flavor, tender texture:
can be substituted for
lettuce
• Can be ready for harvest in
3–4 weeks after sowing.
• More heat tolerant than
Napa. Cold tolerant to 25°F
(-4°C)
• Fairly bolt resistant
• Maruba Santoh, Tokyo
bekana – very similar

11. 1a Brassica rapa var. pekinensis
Maruba Santoh
• A fast-growing chartreuse
(yellow-green) tender-leafed
plant
• Can be harvested as baby leaves
• Or the leaves and wide white
stems of the mature plant
provide crunch for salads
• Or whole plants can be
chopped and lightly cooked
• Only 21 days to baby leaf, 35
days to maturity, and is fairly
bolt resistant
• Photo Ethan Hirsh

12. 1a or b Brassica rapa var. pekinensis or var. chinensis
Tokyo Bekana
• Fast-growing tender
chartreuse frilly, leafy
plant.
• 21 days to baby crop, 45
days to full maturity
• Can be used for salad
leaves during late-summer
lettuce shortages.
• Mild flavor - many people
don’t even notice they are
not eating lettuce!
Young Tokyo Bekana seedlings in our
November hoophouse.
Photo Ethan Hirsh

13. 1b. Brassica rapa var. chinensis
Pak choy, bok choi
• Previously known as
Chinese mustard cabbage
• Sturdy white leaf stems,
big green leaves. Usually
harvested as a head 12"–
15" (30–38 cm) tall
• 45–55 days to maturity
• All are hardy down to 32°F
(0°C), most varieties to
25°F (-4°C)
Photo Johnnys Seeds

14. Pak choy
Red Choi Photo Kitazawa Seeds.
http://www.kitazawaseed.com/seed_443
-77.html
• Can be picked as
individual leaves, for
bunches of mixed
braising greens or stir-
fry combinations
• We grow Prize Choy or
Joy Choi
• There is also red choi (a
45-day, red-veined baby
leaf or maroon-leaved
full-size version)

15. 1c. Brassica rapa var. japonica
Mizuna (kyona)
• Very easy to grow,
tolerates cold wet soil
• Use for baby salads
after only 21 days
• Or thin to 8"–12" (20–
30 cm) apart, to grow
to maturity in 40 days
• Fairly heat tolerant
(well, warm tolerant)
• Cold tolerant to 25°F
(-4°C)
Photo Ethan Hirsh

16. Mizuna
• Mild flavor
• Ferny leaves - add color
and loft in salad mixes
• Regrows vigorously after
cutting
• Available in green or
purple (but Ruby Streaks
mustard is much better
than Purple Mizuna!)
 Mizuna
 Ruby Streaks
 Strap-leaved mibuna
 Purple mizuna
Photo Ethan Hirsh

17. 1d. Brassica rapa var. narinosa
Tatsoi (tah tsoi)
• A small plant, a flat rosette
of shiny, dark green spoon-
shaped leaves and green-
white stems
• 21 days for baby salads; 45
days for cooking
• Mild flavor, an attractive
appearance
• Very cold tolerant, hardy to
10°F (–12°C)
• Easy to grow - here’s how -
Photo Ethan Hirsh

18. Tat soi
• Direct sow and then thin
into salad mixes, leaving
some to mature at 10" (25
cm) across for cooking
greens.
• Can transplant at 6" (15 cm)
• Kitazawa Seeds have a Red
Violet tatsoi/pak choy
hybrid, with an upright habit
Photo Wren Vile
Photo Kitazawa Seeds
http://www.kitazawaseed.com/seed_369-77.html

19. 1e. Brassica rapa var. perviridis or
Brassica rapa var. komatsuna
Komatsuna
• Also known as mustard spinach
(so is Pak Choy!), Summer Fest
• Green or red (purple)
• Baby salad size in 21 days, full
size in 35 days
• A large plant 18" (45 cm) tall
• Pick and bunch individual
leaves
• Or harvest the whole plant
• The flavor is mildly peppery
• Cold-tolerant to 15°F (-9.5°C),
perhaps 10°F (-12°C)
Photo credit Fothergill
Seeds
Photo Fothergill Seeds

20. 1. Brassica rapa or 3. juncea
Yukina Savoy
• like a bigger tatsoi,
• blistered dark green leaves
and stems
• delicious flavor
• about 12" (30 cm) tall
• Tolerant to heat and cold –
down to 10°F (-12°C)
• Transplant at 12" (30 cm)
• 21 days to reach baby size,
45 days to full size
Photo Ethan Hirsh

21. Yukina Savoy
Outdoors in December, after several nights at
16-17°F (-8 to -9°C)

22. Hybrid of 1e. Brassica rapa var perviridis
& 2. Brassica oleracea
Senposai - Our star of Asian greens
• A cross between
komatsuna and regular
cabbage.
• A big plant producing large,
round, mid-green leaves
which are usually
harvested leaf by leaf.
• Cooks quickly (much
quicker than collards)
• Delicious sweet cabbagey
flavor, tender texture.
• Photo Kathryn Simmons

23. Senposai
• Transplant at 12"–18"
(30–45 cm) spacing; it
really will use all this
space
• Grows fast. Only 40 days
to mature.
• Very productive, usually
harvested leaf-by-leaf
• Heat and cold tolerant
(down to 12°F (-11°C)
A bed of senposai 15” apart
in the row, 3 rows in 48”
Photo Kathryn Simmons

24. Senposai in November
the young hoophouse crop is almost ready to
take over from the well-used outdoor crop.
Senposai. Photo Ethan Hirsh

25. 3. Brassica juncea
Red Splendor, Ruby Streaks,
Golden FrillJohnny’s Red Splendor Ruby Streaks
Photo Southern Exposure Seed Exchange
Golden Frill
http://www.evergreenseeds.com

26. Asian-type brassica salad mixes
Wild Garden Pungent Mix,
Brassica juncea, (Wild Garden
Seeds, Fedco)
A cross of pungent Indian mustards
for those who like Big Flavor. 40
days to harvest.
Photos Wild Garden Seeds
Pink Petiole Mix, Brassica rapa
(Wild Garden Seeds, Fedco)
Fast-growing, cold tolerant, adds
a touch of color to the brassica
portion of winter salad mixes. A
varied mix of colors and shapes.
Ready in 40 days.

27. Pseudo-Asian Greens
Pink Lettucy Mustard,
Brassica rapa japonica,
Mild-flavored at all growth
stages
Photo Wild Garden Seeds
Ornamental and garnish kales
and cabbages add color and
texture. We like Nagoya Red and
White and Red Chidori
Photo http://www.extension.iastate.edu

28. 3. Crops to try later
Small and/or short-lived greens
 Hon Tsai Tai, Brassica rapa, (like a purple broccoli raab).
Also known as Choy Sum. Mostly stem with small
clusters of buds. In climates cooler than Zone 7 this
might be productive in the fall. For spring it could be a
challenge most places. It matures in only 35–40 days.
Hardy to 23°F (–5°C).
 Broccoli Raab, Brassica rapa ruvo. We had the same
trouble with this as with Hon Tsai Tai Photo Johnnys Seeds
 Mei Qing Choi, A miniature 6" (15 cm) pak choy. We don’t do well with
miniature crops. These might suit your market, but we do better with
larger vegetables. It matures in less than 45 days, a definite plus
 Vitamin Green/Bitamin-Na/Yokatta-Na, Brassica rapa var. Narinosa. A
slender, white-stemmed plant, about 12" (30 cm) tall. It can be planted 4"
(10 cm) apart, or direct sown and thinned. Tolerates heat and cold. Quick-
growing with good flavor, not pungent: 21 days for salad mix, 45 to full size

29. Crops to try later
Big and sturdy greens
 Tyfon Holland Greens - a strong
plant, a hybrid of komatsuna
with a heading brassica. Could
be good in a survival situation, or
to grow for goats, or to make
green juices.
Hardy down to 20°F (-7°C).
 Mizspoona, Brassica rapa, a
large sturdy plant, 40 days to
maturity. A sweet flavor with a
good balance of mild zinginess.
A gene pool (variable plants).
Mizuna crossed with Tatsoi.
Mizspoona photo Wild Garden Seeds
https://www.wildgardenseed.com

30. More Big Greens
 Chinese Thick-Stem Mustard (SESE,
Fedco, Even' Star Organic Farm,
Maryland). Multiple cuttings of
balanced-flavor salad mix crop to fill
the CSA bags. Extremely cold tolerant.
 Tenderleaf – a big, sturdy, OP plant.
Quick-cooking, mild-flavored, despite
appearances. Selected from a cross of
Tendergreen and tatsoi. Very disease-
resistant and cold tolerant down to
20°F (-7°C). Can be sown later in the
fall than other greens - could be the
solution if your original plan didn’t
work. Can be a useful salad mix crop at
the baby stage.
Chinese Thick-Stem
Mustard. Photo Southern
Exposure Seed Exchange

31. More Big Greens
Toraziroh
 Brassica oleracea algoblabria, a robust producer of high
yields of large leaves with a good, not overpowering flavor.
 Related to Chinese kale or Chinese broccoli.
 Ready in 45 days.
 Bolts sooner than senposai or yakattana
Photos: left http://www.truffulaseedproduce.com, right http://tanicreekfarm.com

32. Photo Kitazawa Seeds
http://www.kitazawaseed.com/seed_051-
68.html
• Transplants of Red Giant Mustard
Photo Southern Exposure Seed Exchange
• Mature Red Giant Mustard
Mustard greens
Mustards such as Red Giant, Osaka Purple, Brassica juncea, and
American Mustards (eg Southern Green Wave) proved too hot for
salads for us, even at 3" (8 cm) leaves. Best cooked. Hardy to light
frosts. Attractive colors. 21 days to baby leaves, 40–45 days full size

33. Chrysanthemum greens (shungiku)
• Chrysanthemum coronarium.
These have a very distinctive
aromatic flavor, which you
may or may not love.
• The flowers are very pretty, if
you give up harvesting the
leaves.
• 21 days for baby greens, 45
days to full size.
Photos
https://plantfreak.wordpress.com

34. 4. Crop requirements for Asian greens
Similar care requirements to other brassicas,
Shallow rooted - Pay extra attention to providing
enough water during hot weather to prevent
bitter flavors and excess pungency,
Do close monitoring of pests, which can build up
large populations during the summer.
Very fertile soils grow the best Asian greens,
Turn in leguminous cover crops
or compost to
provide adequate nutrition.

35. Sow or Transplant?
We almost always transplant brassicas because we
use our growing spaces very intensively.
Transplanting gives the previous crop extra time.
If we have 4 weeks between the end of one crop
and transplants going in, we sow buckwheat to add
organic matter and smother weeds.
We grow a lot of brassicas and our crop rotation is
always pushed and stretched by the amount of
brassicas we’d like to plant – transplanting allows
the soil extra weeks without brassicas.

36. Transplanting for fall crops
In summer, the faster growing types
(Napa cabbage, Tokyo Bekana and
Maruba Santoh) are ready to plant
out 2 weeks after sowing..
Most others transplant best at 3–4
weeks of age (less time than needed
in spring). We transplant outdoors
July 10 - July 31 for early fall crops.
Later is possible.
To minimize transplant shock, water
the plants well an hour before
transplanting, get them in the
ground as quickly as possible and
water again.
Shadecloth or rowcover will help
keep the breezes (if any!) and strong
sun off the plants.
Maruba Santoh transplant.
Photo Ethan Hirsh

37. Irrigation
 Shallow-rooted, need plenty of
water to grow pleasant-tasting
leaves.
 1” (2.5 cm) of water per week
 2” (5 cm) during very hot weather
 Drip irrigation saves water, reduces
disease and weed pressure
 Overhead irrigation can be cheaper
and easier to set up for crops that
will be harvested before much time
has passed.
 Overhead sprinklers can wash off
aphids - could be all the control
you need
Ruby Streaks mustard with drip
irrigation.
Photo Ethan Hirsh

38. 5. Pests and diseases
ProtekNet on hoops
ProtekNet Pest Control Netting is
made of clear high-density
polyethylene with UV resistance
and a lifespan of eight to ten
years. Its light transmission is 90
percent. It is available from Purple
Mountain Organics in Maryland.
The 1.35 × 1.35 mm 60 gm/m2
mesh is one-sixth the length of a
cucumber beetle. It also protects
crops against weather damage.
Mesh fabric with small holes is
better than rowcover in hot
weather - airflow is better and it
heats less.
Photo Dubois Agrinovation

39. Pests : flea beetles
o Garlic spray, Miller’s Hot Sauce,
kaolin and white sticky traps have
been suggested.
o You can also catch them with a
vacuum cleaner, or inside a bucket
coated with Tanglefoot paste (hold
the inverted bucket over the plant,
shake it and catch the jumping
beetles in the goo).
o Hb nematodes will also control them,
as will neem oil or the braconid wasp
Microtconus vittatoe Muesebeck.
ProtekNet – get a small mesh
Brassica flea beetles are a different species from the ones that plague
eggplant, and they can only fly a few hundred yards (meters).
o If we get flea beetles, we use Spinosad, an enzyme produced by a
soil organism.

40. o Harlequin bugs are our worst brassica pests. We usually
pppppppp pick and kill them.
o Aphids are worse in cooler weather (early spring), before their
predators have arrived in high enough numbers.
Insecticidal soaps can be used.
o Caterpillars can be kept off the plants with rowcover or ProtekNet. Bt
(Bacillus thuringiensis) will kill caterpillars if rowcovers fail. Bt
degrades rapidly in sunlight so is best applied early evening or early
morning, whichever seems likely to catch most caterpillars. The
beneficial fungus Beauvaria bassiana infects caterpillars, but can get
costly. Caterpillars have many natural enemies. In our garden the
paper wasps eat caterpillars, and we also have the parasite Cotesia
glomerata
More Pests

41. Even More Pests
o I used to think slugs were an endangered species in
Virginia. When we put up our hoophouse, I found we
were farming them! Slugs can best be caught at night
with a flashlight. (Well, actually with scissors, by
flashlight!)
o Grasshoppers - We are trying to determine when the
young hatch in July, so we know when to be most
attentive to keeping them off our plants.
o Vegetable weevil larvae have caused trouble In our
hoophouse in January. They come out of the soil at
night and make holes in the leaves. We have used
Spinosad against them with some success.

42.  Most of these greens are fast-turnaround crops, so if some
get sick, pull them out and move on in life.
 If it’s fall you can probably sow some spinach to
provide greens without antagonizing the brassica
disease gods.
 Clubroot is perhaps the longest lasting disease, requiring
land to be taken out of brassica production for ten years.
 Other diseases include various molds and wilts.
 See ATTRA’s Cole Crops and Other Brassicas: Organic
Production
Diseases

43. 6. Growing in Spring
In spring we sow in flats in a
greenhouse, to get an early
start.
We transplant spring Asian
greens at 4–5 weeks of age,
about a month before our
last frost date, and use
rowcover for a few weeks.
Direct sowing has the
advantage that thinnings can
be used for salads.
Photo Kathryn Simmons

44. 7. In Summer (for Fall Outdoor Crops)
 We prefer outdoor
seedbeds for summer
sowings, because it is easier
to keep the plants watered.
 We make an outdoor
nursery bed, sow at about
three or four seeds per inch
(5–10 mm apart), and cover
with rowcover or ProtekNet.
 The seedlings emerge in as
little as three days in
summer temperatures.
Bare-root transplants.
Photo credit Ethan Hirsh

45. For Fall Outdoor Crops
We start sowing our fall
Asian greens for outdoor
planting around June 26
and repeat a week later for
insurance (July 3), the
same dates we sow fall
broccoli and cabbage.
Last date for sowing these
crops is about 2 months
before the first fall frost
date. In our case that
means August 14–20.
 Photo credit Kathryn Simmons

46. Season extension
 Fast growing varieties can be
succession sowed for a continuous
supply.
 Cold-hardy types can be harvested all
winter in climates milder than zone 7.
 Or they could be kept alive to revive in
spring and provide earlier harvests
than spring-sown crops.
 Wild Garden Seeds and Even’ Star Farm
specialize in producing seed for very
cold-tolerant varieties.
 Rowcovers on hoops will help keep
these crops in marketable condition,
and improve the microclimate, for
better growth rate.
A well used bed of senposai in
November.
Credit Kathryn Simmons

47. Cold-Hardiness
32F (0C): Some Pak Choy
25F (-4C): Chinese Napa cabbage, Maruba
Santoh, Mizuna, Tokyo Bekana, most Pak Choy
20F (-7C): Tendergreen, Tyfon Holland Greens
15F (-9.5C): perhaps Komatsuna
12F (-11C): Senposai
10F (-12C): Tatsoi, Yukina Savoy, probably
Komatsuna

48. 8. Growing in the winter hoophouse
Hoophouses are the place to be in winter, if you are an Asian
green.  Night-time protection of two layers of
plastic and an air gap – big difference!
 September sowings thrive on sunny
days and grow surprisingly quickly.
 When the daylight falls below ten
hours, growth slows down till spring.
 For most of the winter, our hoophouse
plants are actively growing, not merely
being stored for harvest (as happens in
colder climate zones and outdoors), so
we can continue sowing new
hoophouse crops even in December.
 Brassicas are the most productive
crops in these conditionsPhoto Wren Vile

49. Persephone days and
scheduling winter
hoophouse crops
 When the daylight is shorter than 10 hours a day not much
growth happens. The dates depend on your latitude.
 In Central Virginia, latitude 38° North, this period lasts two
months, from November 21 to January 21.
 The dates are modified by the time it takes to cool the soil and
the air.
 The effective dates for us are closer to December 15 -February
15.
 To harvest in the darkest days of winter you’ll need to plan a
good supply of mature crops to take you through. What has
already grown before this period will provide most of your
harvests.
 Be aware of the increase in days to maturity in winter.

50. Fall outdoor sowings to transplant inside
• Sept 15: pak choy, Chinese cabbage, Yukina Savoy,
Tokyo Bekana, Maruba Santoh,
• Sept 24: Senposai, more Yukina Savoy, mizuna We use
hoops and ProtekNet, and water frequently.
ProtekNet and hoops.
Photo Wren Vile

51. Fall Hoophouse Planting - September
Early September : We clear and
add compost to one of the beds
and sow tatsoi.
Sept 15 and Sept 24: We make
outdoor sowings of crops to
later transplant into the
hoophouse at 2- 4 weeks old.
At the end of September we
clear summer crops from one
more bed, add compost and
work it in. We transplant Tokyo
Bekana and Maruba Santoh at 2
weeks old, Chinese cabbage, pak
choy, Yukina Savoy at 3 weeks.
Photo November hoophouse beds.
Ethan Hirsh

52. Fall Hoophouse Planting - October
Late October we sow more
“filler” Asian greens
In the fourth week of October,
we clear and prepare more beds
and transplant the Senposai,
mizuna, Yukina Savoy at 4
weeks old.
Early October, we sow
some “filler” Asian greens, to
fill gaps later. We try hard to
keep all the space occupied,
mostly using Asian greens,
lettuce and spinach.
Mizuna Photo credit Ethan Hirsh
For more crops, see
my slideshow
Hoophouse in Fall and
Winter on
SlideShare.net

53. Hoophouse Planting –
November and December
Nov 10 we sow more mizuna
Nov 11-20 we sow tatsoi
From Nov 10 on we aim to keep
a fully planted hoophouse, and
as each crop harvest winds
down, we immediately replace
that crop with another.
During December we use the
“Filler” greens plants to replace
casualties and heads of Chinese
cabbage, Pak choy, Yukina
Savoy each day as soon as
we’ve harvested them.
Pak Choy replacing Yukina Savoy here.
Photo Ethan Hirsh

54. Hoophouse Planting –
December to February
 We stop filling gaps with Asian greens
(and lettuces) on Jan 25, and fill all
gaps after that with spinach
transplants, until 2/20. After that we
only fill gaps on edges of beds, leave
centers free for tomatoes, etc.
 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 come to
an end in March or early April
“Filler” transplants. Photo Ethan Hirsh

57. 9. Winter Hoophouse Harvest
Schedule
Harvest of Asian greens starts
in November, with mizuna,
tatsoi and baby brassica mix.
From December we also have
Tokyo Bekana, Maruba
Santoh
The new year starts with
Yukina Savoy and the bigger
greens, including Senposai,
pak choy, Chinese cabbage
feed us till mid-March.
Michihli cabbage
Photo Southern Exposure Seed Exchange.

59. Harvesting
Some of these greens are
harvested as whole heads;
others can be harvested by the
leaf and bunched or bagged.
The open rosette types, such as
tatsoi or the bigger Yukina
Savoy, are usually gathered
closed and banded with plant
ties or rubber bands.
Most can be grown for baby
salad mix. With mizuna we do a
“half buzz-cut,” snipping off
leaves on one half of the plant
an inch (25 mm) above the
ground each time we come by.
Tat soi shown here.
Photo Ethan Hirsh

60. After Harvest
After harvest, get the
crops into shade and a
cooler as soon as you
can.
Some of the heading
types can be stored in a
walk-in cooler for several
weeks, almost as long as
regular cabbage.
Pak Choy shown here
Photo Ethan Hirsh

61. 10. Minimizing nitrate
accumulation in winter
In winter, when light levels are low, beware of high levels of
nitrates in leafy greens.
A health hazard — nitrates can be converted in the body into
nitrites, which reduce the blood’s capacity to carry oxygen
and may be further converted into carcinogenic
nitrosamines.

62. Nitrate accumulation
• Plants make nitrates during the night, and convert them
into leaf material during the day. It takes about six hours
of sunlight to use up a night’s worth of nitrates. In winter,
a small handful of leafy vegetables can exceed the
acceptable daily intake level of nitrate for an adult, unless
special efforts have been made to reduce the levels.
• Spinach, mustard greens (Asian greens)and collards
contain about twice as much as lettuce; radishes, kale and
beets often have two and a half times as much. Turnip
greens are especially high, at 3 times lettuce levels.

63. To keep nitrate levels as low as possible
 Grow varieties best suited for winter;
 Avoid fertilizing with blood meal or feather meal; use organic
compost.
 Ensure soil has sufficient P, K, Mg and Mo
 Water enough but not excessively;
 Provide fresh air as soon as temperatures reach 68°F (20°C), so
that carbon dioxide levels are high enough;
 Harvest after at least four (preferably six) hours of bright sunlight
in winter;
 Avoid harvesting on very overcast days;
 Avoid over-mature crops and discard the outer leaves. Harvest
crops a little under-mature, rather than over-mature;
 Use crops soon after harvest;
 Refrigerate immediately after harvest, store harvested greens at
temperatures close to freezing;
 Mix your salads; don’t just eat Asian greens!

64. 11. Seed saving
 If you plan to grow seed of more than one Asian green, carefully choose
ones that won’t cross. Be aware that crops might be wrongly classified.
 Also beware of brassica weeds.
 For yourself: at least 600 ft (200 m) isolation from other flowering
brassicas.
 To sell seed: ¼ mile (400 m) with barriers or ½ mile (800 m) without.
 Grow at least 120-300 plants, pull out any atypical ones, let the rest bolt.
 Why so many? Brassicas are outbreeding plants and if too few are grown,
they are in danger of inbreeding depression (not enough genetic
diversity)
 Save seed from at least 60 to 75 plants, and preferably 125 to 150.
 As the seedpods dry, pull up the plants, and hang them up to finish drying
under cover. If you have high humidity, use a fan. Hanging plants inside
paper sacks will reduce loss of seeds when the pods shatter.
 Stomp on the bags to shatter the pods, and then winnow and screen the
seeds. See the Saving Our Seed Project guide (in the Resources section)

65. 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
• Kitazawa Seeds kitazawaseed.com/ & Evergreen Seeds have the most choices.
• Evergreen’s helpful clickable list. evergreenseeds.com/asveglis.html
• Fedco Seeds fedcoseeds.com/ and Johnny’s johnnyseeds.com/ have a good
range.
• Wild Garden Seed has many interesting home-bred varieties. Search under
Mustard. wildgardenseed.com
• Even’ Star Farm Ice-bred Seeds localharvest.org/even-star-organic-farm-M9994
• Good Earth Seed Company (Tsang and Ma International)
P.O. Box 5644, Redwood City, California 94063. No English website.
• ATTRA Cole Crops and Other Brassicas: Organic Production attra.ncat.org/attra-
pub/summaries/summary.php?pub=27
• Saving Our Seed Project carolinafarmstewards.org/wp-
content/uploads/2012/05/BrassicaSeedProductionver1_1.pdf an excellent 24-
page guide on organic brassica seed production

66. Producing Asian Greens
©Pam Dawling 2017
Twin Oaks Community, Central Virginia
Author of Sustainable Market Farming
Published by New Society Publishers
SustainableMarketFarming.com
facebook.com/SustainableMarketFarming