Optimizing your asian greens production Dawling 2019

Optimizing your Asian
Greens Production
©Pam Dawling 2019
Twin Oaks Community, Central Virginia
Author of Sustainable Market Farming
and The Year Round Hoophouse
SustainableMarketFarming.com
facebook.com/SustainableMarketFarming

I live and farm at Twin Oaks Community, in central Virginia.
We are located on Monacan land. We’re in zone 7, with an average last
frost April 30 and average first frost October 14. Our goal is to feed our
intentional community of 100 people with a wide variety of organic produce
year round year round. www.twinoaks.org

Outline
1. Meet the Asian Greens
2. Crops I recommend for easy success
3. Crops to try later
4. Crop requirements
5. Growing in spring
6. Growing in summer
7. Growing outdoors in fall
8. Crop protection: rowcover, netting,
shadecloth
9. Growing in the winter hoophouse
a) Packing more in
b) Harvesting
c) Minimizing nitrate accumulation in winter
10. Pests and diseases
11. Seed saving
Pak Choy. Credit Ethan Hirsh

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

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

Advantages of Asian Greens
 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)
Our hoophouse in November
Photo Ethan Hirsh

Asian Greens – Many Types
1. Senposai - cold-hardy
2. Pak Choy
3. Komatsuna - cold-hardy
4. Chrysanthemum greens
5. Yokatta-na
6. Tatsoi - cold-hardy
7. Ruby Streaks, Scarlet Frills
& other mustards
8. Mustard-based salad mixes
9. Mizuna
10. Yukina Savoy- cold-hardy
11. Napa Chinese Cabbage
12. Tokyo Bekana
13. Maruba Santoh
14. Mizspoona
15. Toraziroh
16. Thick-stemmed mustard
17. Hon Tsai Tai
1 2
3
4
5
6
7

Who’s Who – 3 botanical groups
2) The cabbage family, B.
oleracea, of European origin
Kai-lan, Chinese kale,
Toraziroh
3) The Chinese Mustard
family, B. juncea
Ruby Streaks (shown here,
Photo Johnnys Seeds),
Golden Frills, Red Rain, Wild
Garden Pungent Mix
1) The turnip family, Brassica rapa, of
Asian origin
a) Brassica rapa var. pekinensis (napa
cabbage, michihli, celery cabbage)
b) B. rapa var. chinensis (bok choy)
c) B. rapa var. japonica (mizuna)
d) B. rapa var. narinosa (tatsoi, Yokatta-
na)
e) B. rapa var. perviridis (komatsuna)
Different sources use different names
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

2. Crops I recommend
1a. Brassica rapa var. pekinensis.
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)
• Stores better than michihli
types
Napa cabbage

1a. Brassica rapa var. pekinensis
Michihli (Cylindrical Wong Bok)
Chinese cabbage
• Produces 16" (40-cm) tall heads
6" (15 cm) across.
• More productive than Napa
cabbage in the same space
• Very tender, light green leaves
• Great 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

1a Brassica rapa var. pekinensis
Celery cabbage (pe tsai)
Photo credit Johnnys Seeds
• 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 3–4
weeks after sowing.
• More heat tolerant than Napa.
Cold tolerant to 25°F (-4°C)
• Fairly bolt resistant
• Maruba Santoh and Tokyo
bekana are very similar

1a or b Brassica rapa var. pekinensis or var. chinensis
Tokyo Bekana
• Fast-growing tender
chartreuse frilly, leafy plant.
• Mild flavor
• 21 days to baby crop, 45 days
to full maturity
• The leaves and wide white
stems of the mature plant
provide crunch for salads
• Mature plants can be chopped
and lightly cooked Young Tokyo Bekana seedlings in our
November hoophouse.
Photo Ethan Hirsh

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

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

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)

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

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

3. Brassica juncea
Red Splendor, Ruby Streaks,
Golden Frills
Johnny’s Red Splendor Ruby Streaks
Credit Southern Exposure Seed Exchange
Golden Frills

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

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

1e. Brassica rapa var. perviridis or Brassica rapa v. 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

1. Brassica rapa
Yukina Savoy
• Like a bigger tatsoi, 12"
(30 cm) tall
• Blistered dark green
leaves and green stems
• Delicious flavor
• Tolerant to heat and cold
– down to 10°F (-12°C)
outdoors
• Transplant at 12" (30 cm)
• 21 days to reach baby
size, 45 days to full size
Photo Ethan Hirsh

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

Koji and Red Cloud
In our experience, OP Yukina
Savoy is more cold-hardy and
bolt-resistant than hybrid Koji.
Koji is an F1 hybrid tatsoi for
baby leaf or bunching. Johnny’s
Seeds, who sell it to replace
Yukina Savoy, report that it is
more upright and faster-
maturing (21 days to baby leaf,
43 days to full size). Space 12”
(30 cm) apart.
Red Cloud is Johnny’s smaller,
burgundy hybrid tatsoi
Red Cloud photo Johnny’s Seeds

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

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

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

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.

• We sow winter radish outdoors
on August 4. (China Rose and a
daikon. )
• We harvest in October or
November before temperatures
drop to 20°F (-7°C)
• Stores well in perforated plastic
bags under refrigeration
• Popular for making Kim Chee, as
well as for salads and stir-fries.
Frosty daikon. Photo Bridget Aleshire
Winter Radish, Including Daikon

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

Big 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

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, down to 6°F (-14°C).
 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 Heirloom
Seed Supply

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

4.Crop Requirements for Asian Greens
Similar care requirements to other brassicas,
Closely monitor 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.
 Shallow rooted - Pay extra attention to providing
enough water during hot weather to prevent bitter
flavors and excess pungency,

Irrigation
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

Sow or Transplant?
We almost always transplant brassicas because we
use our growing spaces very intensively.
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.
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.

5. 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

6. Summer Tokyo Bekana
Provided you can keep bugs off, and supply enough water, Tokyo
bekana and maruba santoh will germinate and grow quickly to
provide mild-flavored salad leaves during late-summer lettuce
shortages. Full size in just 5 weeks from sowing in warm weather.

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

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

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

Cold-Hardiness
 32F (0C): Some Pak Choy
 25F (-4C): Chinese Napa cabbage, Maruba Santoh,
Mizuna, most Pak Choy, Red Giant Mustard, Tokyo Bekana,
 20F (-7C): Tendergreen, Tenderleaf, Tyfon Holland Greens
 15F (-9.5C): perhaps Komatsuna
 12F (-11C): Senposai (may be OK down to 10F (-12C)
 10F (-12C): Green-in-Snow mustard, probably Komatsuna;
Tatsoi, Yukina Savoy, winter radishes
 6F (-14C): Thick-stemmed Mustard
Spring Bolt Resistance
In spring the order of bolting of Asian greens is: tatsoi, Maruba
Santoh, Tokyo bekana, Koji, Napa cabbage, pak choy, Yukina
Savoy, Komatsuna, mizuna, leaf radish.

Hot Weather Season Extension
Insect Netting Shadecloth
Asian greens have no problem
germinating in temperatures up
to 95F (35C)
ProtekNet is available from
Purple Mountain Organics,
duboisag.com and other
suppliers. Choose mesh size

Cold Weather Crop Protection
Three basic levels of protection:
1. Rowcover
2. Quick Hoops and Caterpillar
Tunnels
3. Hoophouses (High Tunnels)
Rowcover
• keep frost-tender crops alive
and productive beyond the first
few fall frosts
• keep hardy crops alive in winter
• protect young plants in early
spring.Photo Kathryn Simmons

Rowcover in the Hoophouse
On very cold winter nights (below 8F (-13C) outdoors) and
frosty nights after transplanting tender crops, we use thick
rowcover – Dupont Xavan 5131 (aka Typar). 1.25 oz/sq yd
spunbonded polypropylene; 75% light transmission; about 6 F
(3.3 C) degrees of frost protection; lasts for 6 years or more.
Rowcovers at
the ready in
winter.
Photo Wren Vile

Rowcover How-to
 Lightweight, easy to use and
store
 To protect against cold, you
need thick rowcover.
 Thinner types are to protect
from insects - can be doubled
up for cold weather.
 Hold down edges with bags of
rocks or sand, plastic jugs of
water, or metal or wooden
stakes lying along the edges.
We think polypropylene rowcover lasts longer and is tougher than polyester (Reemay)
• Hoops keep rowcover
from sticking to frozen
leaves and reduce
abrasion.
• 9- or 10-gauge wire.
• In winter we use double
wire hoops

Quick Hoops and Caterpillar Tunnels
Quickhoops
• Cover more than one bed, close to
the ground.
• Can be covered with rowcover
topped by hoophouse plastic for the
winter.
• Or, once plants are established, if
they can withstand cold nights, they
may benefit more from clear plastic
instead of rowcover over hoops.
Photo Johnnys Seeds
Caterpillar tunnels
• Usually tall enough to walk in
• Sometimes narrower than
Quickhoops. 2 beds + 1 path
• Plastic or rowcover held down by
ropes at each hoop.
• Can be used for summer or winter.
• No sandbags.
Photo MOFGA

Try a hoophouse (high tunnel)
• A structure of hoops (bows) covered with one or two
layers of UV-resistant polyethylene.
• Double layer hoophouses use a small electric blower to
inflate the space between the layers of plastic
• This adds insulation and strength against snow loads
and wind.
• Crops are usually grown directly in the ground
• In winter the soil holds some warmth
• Roots can grow deep, crops grow quickly

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

Our Hoophouse at Twin Oaks
• We have a 30’ x 96’ FarmTek ClearSpan gothic arch hoophouse,
with two layers of plastic.
• We put it up in 2003, and like many growers our primary goal was
growing more winter greens, early tomatoes and peppers.
• We divided our hoophouse lengthwise into five 4’ beds and a 2’
bed along each edge.
• Our paths are a skinny 12” wide - maximum growing space. Your
paths could be wider – you are in charge!
• We plant many different cool weather crops in September and
October to harvest till April and May

September Hoophouse Planting
This presentation only covers
Asian greens – we grow other
crops too!
Early September : We clear and
add compost to one of the beds
and sow tatsoi.
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

Use hoops and insect netting, and water frequently
Sept 15: pak choy, Chinese cabbage, Yukina Savoy, Tokyo
bekana, Maruba Santoh
Sept 24: Senposai, more Yukina Savoy, mizuna
September Outdoor Sowings
to Transplant Inside
ProtekNet and hoops. Photo Wren Vile
Transplant into the
hoophouse at 2–4
weeks old.

For more crops, see
my slideshow
Hoophouse in Fall and
Winter on
SlideShare.net
October Hoophouse Planting
10/10, we sow some “filler”
Asian greens, to fill gaps later.
10/20 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.
We try hard to keep all the
space occupied, mostly using
Asian greens, lettuce, spinach.
10/2 we sow our first
brassica salad mix (Harvest
10/29-12/22)
Mizuna Photo credit Ethan Hirsh

Filler Greens
• As well as scheduled plantings, we sow a few short rows of
Senposai, Yukina Savoy, Maruba Santoh, Tokyo Bekana and
spinach and lettuce to transplant into gaps as soon as they
occur.
• We simply dig them up, replant where needed, water well.
• Alternatively you could keep some plug flats of these plants
handy.
Filler greens (and
lettuce and
spinach).
Photo by Kathleen
Slattery

Persephone days and
scheduling winter
hoophouse crops
 When the daylight length is below 10 hours, little growth happens.
 This period depends on your latitude. At 38°N, it’s Nov 20–Jan 20
 The slow growth is modified by the time to cool the soil.
 In practice, the dates of slowest growth for us are Dec 15–Feb 15.
 To harvest in mid-winter, plan to grow a good supply of mature crops
before this period. They will provide most of your harvests.
 For most of our winter, the hoophouse plants are actively growing,
not merely being stored for harvest (as happens in colder climate
zones and outdoors)
 We continue sowing new crops even in December and January.
 Be aware of the increase in days to maturity in winter.
For details, see my slideshow Hoophouse in Fall and Winter on SlideShare.net

November Hoophouse Planting
Nov 10 we sow more mizuna and Frilly Mustards We
then have a fully planted hoophouse.
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.
Nov 11-20 we sow more tatsoi
Bed of tatsoi.
Photo Ethan Hirsh

December Hoophouse Planting
During December we use the
Filler Greens plants to replace
casualties and heads of Tokyo
bekana, Maruba Santoh,
Chinese cabbage, Pak choy,
Yukina Savoy each day as
soon as we’ve harvested
them.
We sow our 2nd brassica salad
mix 12/9 (Harvest 3/4-3/29)
Pak Choy replacing Yukina
Savoy here.
Pak Choy replacing Yukina Savoy here.
Photo Ethan Hirsh

January/February Hoophouse Planting
Until Jan 25, fill gaps with
Asian greens, spinach or
lettuces as appropriate,
From Jan 25 to Feb 20 fill all
gaps everywhere with spinach
transplants
From Feb 20, only fill gaps on
the outer thirds of the beds,
leaving centers free for
tomatoes, etc.
Feb 1 we sow Frills #3 and
Brassica Salad Mix #3 (Harvest
3/8-4/15)
Feb 9 we sow Brassica Salad
Mix #4 (Harvest 3/27-4/30)
Filler Greens transplants.
Photo Ethan Hirsh

For details, see my slideshow
Hoophouse in Fall and Winter on
SlideShare.net
Packing More Crops in
Keep the space filled with useful
crops.
It’s important to know when
crops will bolt, and how to plant
sensible quantities. Strategies:
• Transplant from outside in fall
• Filler crops for gaps
• Fast catch crops for big gaps
• Interplanting to keep the
greens later into spring
• Follow-on crops,
• Succession planting
December harvests Photo Wren Vile

• 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.
Packing more in –
Brassica (Mustard) Salad Mixes

Fast Catch Crops
Tatsoi. Credit Wren Vile
Ready in 30–35 days in fall,
longer in winter:
• many Asian greens:
Chinese Napa cabbage,
Komatsuna, Maruba
Santoh, mizuna, pak
choy, Senposai, tatsoi,
Tokyo Bekana and Yukina
Savoy.
• radishes (both the fast
small ones and the larger
winter ones).
• Mustard salad mixes
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.

Packing more in – keep greens for
March and April
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.
Having greens during the Hungry
Gap of March and early April is
very valuable
Our winter and spring crops come
to an end in March or early April
Tomatoes transplanted in
the middle of a lettuce mix
bed. This works with Asian
greens too. Photo Kathryn
Simmons

A sequence of different crops occupying the same space over time.
Sometimes confusingly called “Succession Planting”.
• 11/17: We follow our 1st radishes with 3rd scallions
• 12/23: 1st baby brassica salad mix with 5th radishes
• 12/31: Some of our 1st spinach with our 2nd baby lettuce mix
• 1/15: Our 1st tatsoi with our 4th spinach
• 1/16: Our Tokyo Bekana with spinach for planting outdoors
• 1/24: Our pak choy & Chinese cabbage with kale & collards for
outdoors
• 2/1: Our 2nd radishes with our 2nd baby brassica salad mix
• 2/1: Our 1st Yukina Savoy with our 3rd mizuna/frilly mustards
• 2/1: Some of our 1st turnips with our 3rd baby lettuce mix
• 2/1: More of our 1st spinach with dwarf snap peas
Follow-on Winter Hoophouse Crops
(not all of these are Asian greens!)

Succession Planting for
Continuous Harvests
 To get harvests starting an
equal number of days apart,
vary the interval between one
sowing date and the next
according to growth rate.
 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.
For all the details, see my slideshow
Succession Planting for Continuous
Harvests on SlideShare.net
Tatsoi. Photo Ethan Hirsh

• Mizuna (and other frilly mustards)
–#1, transplanted 10/24, harvest 11/5-2/10.
–#2, sown 11/10, harvest 1/20-4/3,
–#3, sown 3/1, harvested 4/10-5/10
• Tatsoi
–#1, sown 9/7, harvest 10/30-12/28.
–#2, sown 11/15, harvest 2/12-3/2.
• Yukina Savoy
–#1, transplanted 10/10, harvest 12/5-1/31.
–#2, sown 10/24, harvest 1/8-3/2
Our Asian Greens Succession Crops

Making a Close-Fit Plan Using Graphs
A 6 step process (here’s step 1 to step 4):
1. Gather sowing and harvest start and finish
dates for each planting of your chosen crop
2. Make a graph for that 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.

Radish Succession Crops Graph
with Smoothed Line

 Count the days from first harvest of the first sowing to the first
harvest of the last sowing:10/1–3/18=30+30+31+31+28+18=168
 Use the harvest end dates to see roughly how long a patch of
radishes lasts (how often you want a new patch coming on line)
 Divide the harvest period into a whole number of equal
intervals of that length. If we want new radishes every 34 days,
we’ll need 5 equal intervals between plantings (34 x 5 = 170).
 Five intervals means 6 plantings. (P-I-P-I-P-I-P-I-P-I-P)
 The harvest start dates will be 10/1, 11/4, 12/8, 1/11, 2/14,3/20
 Draw a horizontal line from each harvest start date to the graph
line – see next slide
Step 5 Divide the Harvest Period into
a Whole Number of Equal Segments

Radish Succession Crops
Harvest Start Dates

Radish Succession Crops
Sowing Dates

Step 6. See the Sowing Dates that
Match Your Harvest Start Dates
 Drop a vertical line down to the horizontal axis from each place
that a horizontal line meets your smoothed curve.
 Read the planting dates on the horizontal axis at these points
 Write these planting dates on your schedule: 9/7, 9/30, 10/28,
11/22, 12/20, 1/27
 Sowing intervals are 23, 28, 25, 28, 38 days – longer in Dec-Jan,
as the Jan sowing will catch up some with the Dec sowing.
 If your planting plans exceed the space you’ve got, simply
tweaking to a less frequent new harvest start could free up
space to grow something else.
 Also consider a gap in radish supply, if other crops could
make better use of the space.

Hoophouse Asian Greens Harvest Dates
• October: tatsoi.
• From November onwards: As October plus brassica salad mix,
mizuna, frilly mustards, leaves of Tokyo bekana and Maruba Santoh.
• From December: As November plus senposai and Yukina Savoy.
• From January: As December
• During December: whole plants of Tokyo Bekana, Maruba Santoh.
• During January: heads of Chinese cabbage, pak choy.
• Having the heading crops in December and January gets us through
the slow-growth period.
• Most loose-leaf crops last until mid-March or later.
• Yukina savoy. Credit Ethan Hirsh

Harvesting Methods
Don’t harvest frozen crops.
Some of these greens are
harvested as whole heads;
others can be harvested by
the leaf and bunched or
bagged.
Most Asian greens can be
grown for baby salad mix.
With mizuna and Frills 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
harvest.
Tat soi.
Photo Ethan Hirsh

Cut and Come Again Harvesting
With baby salad mixes, cut the
plants above the growing point
with scissors or shears every 10–
35 days, when the plants are 3”-
4” (8-10 cm) tall.
Non-heading and rosette Asian
greens can be harvested by the
leaf and bunched or bagged. The
center will keep growing.
Don’t harvest too much: “8 for
Later,” leave at least the inner 8
leaves. (Senposai manages OK
with 6 leaves)
Tatsoi. Credit Wren Vile

Harvesting Whole Plants
We harvest whole Maruba Santoh
and Tokyo Bekana plants in
December and Chinese cabbage
and pak choy in January. These
provide good harvests in the
slowest growing time of year.
Open rosette types, (tatsoi or the
bigger Yukina Savoy) are usually
gathered closed and banded with
plant ties or rubber bands.
We switch from harvesting by the
leaf to harvesting whole heads
when growth speeds up, and
bolting looks likely.
Joi Choi pak choy.
Photo Johnny’s Seeds

Minimize 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.
Photo credit
Kathleen
Slattery

Nitrate Accumulation in Winter
• Plants make nitrates during the night, and convert them
into leaf material during the day, in the process of
photosynthesis.
• It takes about 6 hours of sunlight to use up a night’s worth
of nitrates.
• A small handful of winter leafy vegetables can exceed the
acceptable daily intake level of nitrate for an adult, if
harvested early in the day
Photo Mark Cain
Dripping Spring Gardens

Keep Nitrate Levels as Low as Possible
Grow varieties best suited for winter;
Avoid animal fertilizers; 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;
Refrigerate immediately after harvest, store harvested greens at
temperatures close to freezing;
Use crops soon after harvest;
Eat a mixed diet; don’t just eat turnip greens, kale and spinach.

10. 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.

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. We spray the aphids
with soap 3 times, 5 days apart, or later in the season we bring in
ladybugs.
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

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.
Even More Pests

 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

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) 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 atypical ones, let the rest bolt.
 Why so many? Brassicas are crossbreeders, needing genetic diversity
 Save seed from at least 60 plants, preferably 125–150.
 As the seedpods dry, pull up the plants, and hang them up under
cover. Use a fan if it’s humid. Hang plants inside paper sacks to
reduce loss of seeds from shattered pods.
 Stomp on the bags to break the pods, then winnow and screen the
seeds. See the Saving Our Seed Project guide (in the Resources)

Seed Crops
• Clifton Slade in Virginia overwintered
collard greens in a hoophouse in zone 7b
for seed.
• Clif direct seeded 12/1.
• On 2/15 he started rolling up the side
curtains every day, to vernalize the plants.
• 90 days from sowing, 3/1, he had greens.
• 100 days from sowing, the plants flowered.
Seed matured earlier than outdoors.
• Clif had 100 lbs (45 kg) of pods, which gave
30 lbs (14 kg) of cleaned seed.
• The yield was double that grown outdoors.
• Seeds were bigger than outdoor-grown
seed, with good germination

Resources – Asian Greens
 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
 Asian Vegetables, Sally Cunningham, Chelsea Green
 The Chinese Kitchen Garden, Wendy Kiang-Spray, 2017, Workman
Publishing
 Kitazawa Seeds kitazawaseed.com/ Many choices.
 Evergreen Seeds helpful clickable list. evergreenseeds.com/asveglis.html
 Fedco Seeds fedcoseeds.com/ , Johnny’s johnnyseeds.com/ - good ranges.
 Wild Garden Seed. Search under Mustard. wildgardenseed.com
 Even’ Star 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.

Resources - Season Extension
 Extending the Season: Six Strategies for Improving Cash Flow Year-
Round on the Market Farm Lynn Byczynski
 Janet Bachmann, Season Extension Techniques for Market Gardeners,
ATTRA, 2005. attra.ncat.org/attra-
pub/summaries/summary.php?pub=366
 Fall and Winter Gardening Quick Reference, Southern Exposure Seed
Exchange, www.southernexposure.com/growing-guides/fall-winter-
quick-guide.pdf
www.johnnyseeds.com. Growers’ Library, Winter growing guide
www.motherofahubbard.com Winter Vegetable Gardening
 Solar Gardening: Growing Vegetables Year-Round the American
Intensive Way, Leandre Poisson, Gretchen Poisson and Robin
Wimbiscus, 1994, Chelsea Green

Resources – More Detail
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
The Organic Seed Grower, John Navazio, 2014, Chelsea Green
USDA plant database plants.usda.gov/java/
International Code of Nomenclature for algae, fungi, and plants
2018 iapt-taxon.org/nomen/main.php
Missouri Botanical Garden Plant FInder:
missouribotanicalgarden.org/plantfinder/plantfindersearch.asp
x. Search Brassica rapa, for example
vegvariety.cce.cornell.edu/main/showVarieties.php Search for
“Mustard”

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