Asian Greens in the Winter Hoophouse 75 min 2022.pdf

Asian Greens in the
Winter Hoophouse
©Pam Dawling 2023
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’re in US Winter hardiness zone 7a,
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.
www.twinoaks.org

Land Acknowledgement
I live and work on the ancestral and traditional
territory of the Monacan Nation, who lived in what is
now Louisa County and other parts of Central Virginia
before white settlement in the 1700s. Land
Acknowledgement is a way to help fight obliteration
of Indigenous history. I am deeply grateful to the
Monacan People for letting Twin
Twin Oaks Community live and
farm on their land.

Outline
• Introduction to hoophouses
• Meet the Asian Greens
• My favorite Asian Greens
• More Asian greens
• Crop requirements,
• Scheduling considerations
• Planting calendar
• Packing more in
• Harvesting
• Minimizing nitrate accumulation
• Pests and diseases
• Resources
Pak Choy. Credit Ethan Hirsh

What is a Hoophouse (High Tunnel)?
• A structure of hoops (bows) covered with one or two layers of
UltraViolet-resistant polyethylene.
• Double layer hoophouses use a small electric blower to inflate
the space between the layers of plastic, providing about 8F
(4.5C) degrees of winter night-time temperature difference.
• The air gap also adds strength against snow loads and wind.
• Single layer hoophouses are not much warmer than outdoors
at night, so you need inner tunnels with rowcover.
• Crops are usually grown directly in the ground

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 the space lengthwise into five 4’ beds with 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!

Winter Hoophouse Overview
 We plant many different cool
weather crops in September
and October to harvest till April
and May
 In our hoophouse, without
inner rowcover, salad greens
survive nights with an outdoor
low of 14°F (-10°C).
 If it will be 8°F (-14.5°C) or less
outside, we add thick rowcover.
 With rowcover, hoophouse
salads can survive when it’s
-11°F (-24°C) outside
For details, see my slideshow
Hoophouse in Fall and
Winter on SlideShare.net
Crop quality, especially leafy greens, is
superb. Photo Wren Vile

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!
 Fall 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 conditions
Photo Wren Vile

Winter Hoophouse Benefits
We are amazed at how incredibly productive hoophouses are!
• Crop quality, especially leafy greens, is superb.
• The soil stays warmer. Roots can grow deep.
• Rate of growth of cold-weather crops is much faster inside
• Plants tolerate lower temperatures than they can outdoors.
• Working in winter inside a hoophouse is much more pleasant
than dealing with frozen rowcovers and hoops outdoors.
We harvest crops
in the hoophouse
after the outdoor
crops slow down
in October, or on
days with really
bad weather.

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

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

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

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
and other mustards
 More on the next slide.
 Also:
– Mustard salad mixes
– Mizuna
 Large sturdy greens:
– Mizspoona
– Toraziroh
 Stems and buds:
– Hon Tsai Tai
1 2
3
4
5
6
7

Other Asian Greens I recommend
Napa cabbage, Photo
Kashruth Council of Canada
Tokyo bekana (Maruba Santoh is
similar). Wren Vile
Young pak choy (bok choy)
Pam Dawling
Mizuna (bolting late April.
Pam Dawling
Tatsoi. Pam Dawling
Chinese Thick-Stem
Mustard. Cold tolerant
down to -14°C. Heirloom
Seed Supply
Yukina Savoy. Ethan Hirsh
Scarlet Frills. Johnny’s Seeds

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

Our Favorite Asian Greens
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

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 black speck than
Napa cabbage
• Bolts earlier than Napa
• Cannot be stored as long.
• We like Jade Pagoda (72 days)
and the O-P Michihli (72 days) Photo Southern Exposure Seed Exchange

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

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

Maruba Santoh
• Another 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

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)

Mizuna/Kyona
• Ferny leaves - add loft
in salad mixes
• Mild flavor
• Available in green or
purple (but Ruby
Streaks is much better
than Purple Mizuna!)
• Regrows vigorously
after cutting
Harvesting Mizuna
Photo Wren Vile

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

Ruby Streaks, Golden Frills, Scarlet
Frills, Red Rain
Johnny’s Red Splendor Ruby Streaks
Credit Southern Exposure Seed Exchange
Golden Frills

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

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

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

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

Tall narrow space-saving crops
Komatsuna is good value for the space,
because it has a small footprint.
Other tall narrow crops include:
Michihli cabbage
Yokatta-na (Vitamin Greens)
Gai Lan/Kai Lan (Chinese broccoli),
Yau Choy
For details, see my slideshow Optimizing Your
Asian Greens Production on SlideShare.net

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.
Senposai. Photo Ethan Hirsh

Senposai
• Senposai is heat and cold
tolerant (down to 12°F/
-11°C)
• a big plant with large,
round, mid-green leaves.
• Transplant it at 12"–18"
(30–45 cm) spacing; it
really will use all this space
• Grows fast. Only 40 days to
mature.
• It is very productive.
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.

Asian-inspired Greens
Vibrant Ultraviolet, Midnight
purple lobed leaves with vibrant
magenta-violet petiole and veins.
Plant this for the coldest seasonal
salad. 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

• We sow winter radish outdoors
on August 4. (China Rose and a
daikon.) Sow a few weeks later
in the hoophouse.
• Harvest before temperatures
drop to 20°F (-7°C) in the
hoophouse.
• 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

Big Sturdy Greens
 Tyfon Holland Greens - a strong
plant, a hybrid of komatsuna
with a turnip. Could be good to
make green juices, or in poor
soil, or to grow for livestock.
Hardy down to 10°F (-12°C).
https://garden.org/plants/view/125987/Holland-
Greens-Brassica-rapa-Tyfon/Photo by sallyg
 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.
https://www.wildgardenseed.com
Mizspoona photo Wild Garden Seeds

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

Even 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

• Hardy to light frosts
• American Mustards (eg Southern Green Wave)
• Asian mustards such as Red Giant, Osaka Purple, Brassica juncea,
• Attractive colors. 21 days to baby leaves, 40–45 days full size
Green Wave Mustard. Photo
http://www.rareseeds.com
Mature Red Giant Mustard Photo Planet Natural
Mustard Greens

Small and/or short-lived crops
 Hon Tsai Tai (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).
Photo credit Johnnys Seeds
 Broccoli Raab We had the same trouble with this as with
Hon Tsai Tai
 Mei Qing Choi. A miniature 6" (15 cm) pak choy. 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 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 its full size

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

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
Crops need plenty of water to
grow pleasant-tasting leaves.
1” (2.5 cm) of water per week
is often enough, except
during very hot weather
We have drip irrigation. In
the middle of winter, not
much water is needed, and
we try to only water when a
relatively mild night is
forecast.
Drip irrigation saves water
and reduces disease and
weed pressure. Only the
crops are watered, not the
whole area. The leaves do not
get wet.

Components of a drip system
• Frost proof hydrant
• Y valve
• Timer
• Filter
• Pressure reducer
• Connector
• Header pipe

Overhead Irrigation
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
Using a lawn sprinkler in the hoophouse in October to wash down salts accumulated on the
soil. Photo Pam Dawling

Ventilation
• Even in cold weather, plants need fresh air! High-density
cropping can really use up the carbon dioxide in a closed
hoophouse very quickly. When this happens, photosynthesis
crashes and plant growth becomes limited.
• However - soil high in OM contains high levels of organisms
that produce carbon dioxide. Dense plant canopies can trap this
near soil level, where it is most useful.

Cold-Hardiness of Asian Greens
 32°F (0°C): Some Pak Choy
 25°F (-4°C): Chinese Napa cabbage, Maruba Santoh,
Mizuna, most Pak Choy, Red Giant Mustard, Tokyo Bekana,
 20°F (-7°C): Tendergreen, Tenderleaf, Tyfon Holland Greens
 15°F (-9.5°C): perhaps Komatsuna
 12°F (-11°C): Senposai (may be OK down to 10°F (-12°C)
 10°F (-12°C): Green-in-Snow mustard, probably Komatsuna;
Tatsoi, Yukina Savoy, winter radishes
 6°F (-14°C) Thick-stemmed Mustard
These are outdoor winter-kill temperatures. In a double-layer
hoophouse, night-time temperatures will stay 8F (4.5C)
degrees warmer than outdoors, and plants can withstand
colder temperatures than they can outside

Insect Netting
ProtekNet on hoops
Mesh fabric with small holes is
better than rowcover in hot
weather - airflow is better and
it heats less.
ProtekNet Pest Control Netting
is made of clear high-density
polyethylene with UV
resistance and a lifespan of 8-
10 years. Its light transmission
is 90%. It also protects crops
against weather damage.
 ProtekNet is available from Purple
Mountain Organics, duboisag.com and
other suppliers. Choose mesh size
Photo Pam Dawling

Rowcover in the Hoophouse
On very cold winter nights (below 8°F (-13°C) outdoors), 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

Germination Temperatures
• Will your crop actually germinate at the
prevailing temperature? Don’t waste
space and time.
• Asian greens have no problem
germinating in temperatures up to 95°F
(35°C)
• Soil temperature info on
www.greencastonline.com
• How many days does your chosen crop
need to germinate in your conditions?
• Use a soil thermometer, and consult
charts of days to germination at various
temperatures
• Find them in my book, The Year-Round
Hoophouse
• Lettuce seedlings emerging. Photo Kathryn Simmons

Cool Weather Crop Rotations
Lettuce,
chicories
Brassicas
Spinach,
chard
and beets
 Cool weather crops mostly fall
into 3 crop families
Lettuce and chicories
Brassicas
Spinach, chard and beets.
 2 other families are grown in
smaller amounts
Legumes
Alliums
 Rotate the main families each
cool season.
 Use the less common families
to fill out the space, ad hoc.

When to Plant - Days to Maturity
Find the number of days to maturity (from the catalog).
Is that number from seeding to harvest or transplant to
harvest?
Work back from each target harvest date, subtracting days to
maturity, to give the planting date.
Days to maturity in catalogs are generally for spring planting
once conditions have warmed to the usual range for that crop.
When growing in late fall, winter or early spring add about 14
days - seedlings grow slower when chilly.
In winter when the air temperature is below 39°F/4°C, plants
don’t grow much at all – ignore those days from your
calculations. See www.weatherspark.com, Average hourly
temperature graph.
 “Days to Maturity” usually means “Days to First Harvest” which
may not be the same as “Days to Full Harvest”.
With carrots it doesn’t matter exactly what size they are, but an
immature Chinese cabbage is just no good. Add another week

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.

Transplanting Fall Crops
In warm weather, 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 in the early fall.
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.

Mizuna, Ruby Streaks before
Scarlet Frills, Golden Frills
Spring Bolt Resistance
• In spring the order of bolting of Asian greens is:
• Tatsoi 1/7-1/14 (#2 2/21),
• Michihli 1/7,
• Koji 1/7,
• Maruba Santoh, Tokyo bekana 1/9
• Napa cabbage 1/23,
• Pak choy 1/23,
• Mizuna 1/25 (#2 3/1, #3 3/20, #4 4/19),
• Yukina Savoy 2/5 (#2 2/20),
• Komatsuna,
• Leaf radish,
• Mustards
• Toraziroh
• Senposai 3/7
• Yokattana
Bolting mizuna and
other frilly greens.
Pam Dawling

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
10/20 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.
10/2 we sow our first
brassica salad mix (Harvest
10/29-12/22)
10/10, we sow some “filler”
Asian greens - a few short
rows of Senposai, Yukina
Savoy, Maruba Santoh, Tokyo
Bekana to transplant into
gaps as soon as they occur.
Mizuna
Photo credit
Ethan Hirsh

November Hoophouse Planting
Nov 10 we sow more mizuna and Frilly Mustards We
then have a fully planted hoophouse.
From Nov 10 on we work to keep a full house, mostly
using Asian greens, lettuce, spinach, 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, we 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
• Fast catch crops for gaps
• Filler crops for gaps
• Interplanting to keep the
greens later into spring
• Follow-on crops,
• Succession planting
December harvests Photo Wren Vile

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.

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

• 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.
Brassica (Mustard) Salad Mixes

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 April or early May
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 11/1–1/25
– #2, sown 10/30, harvest 1/20?-3/1
– #3 sown 11/9, harvest 2/26-3/20,
– #4, sown 2/1, harvested 3/24-4/19
• Tatsoi
– #1, sown 9/7, harvest 10/30-12/28.
– #2, sown 11/15, harvest 2/12-2/21. Last
worthwhile sowing date.
• Yukina Savoy
– #1, transplanted 10/10, harvest 12/5-1/31.
– #2, sown 10/24, harvest 1/8-2/20
– #3, sown 2/15, harvest ??
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

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

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

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.
Some benefit from
standing the leaves in a
little water
Pak Choy shown here
Photo Ethan Hirsh

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

Minimize nitrate accumulation
We have upset the balance by increasing the warmth but not
the light. In winter, when light levels are low, high levels of
nitrates can accumulate in leaves.
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.

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. It is a broad spectrum insecticide, so be mindful.

In cooler weather, our worst
hoophouse pests are aphids and
vegetable weevil larvae.
• We spray the aphids with soap
3 times, 5 days apart, or later
in the season we bring in
ladybugs.
• VWL live in soil, come out at
night to eat holes in brassica
leaves. We killed them with
Spinosad.
• Slugs can be trapped or
caught at night by flashlight!
Pests
Credit ipm.ncsu.edu

 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

Resources – General (Sept 2022)
ATTRA attra.ncat.org/ Season Extension Techniques for Market
Farmers, etc.
SARE www.sare.org/ A searchable database of research findings. See
Season Extension Topic Room
eorganic.info is the organic agriculture community of practice with
the Cooperative Extension System. Publications, webinars, videos,
trainings and support. Reliable information.
Growing Small Farms: growingsmallfarms.ces.ncsu.edu/ Farmer
Resources.
Jean-Paul Courtens, Roxbury Farm
https://www.roxburyfarm.com/roxbury-agriculture-institute-at-philia-
farm Whole farm Approach; Biodynamic Practices; Harvest Manual;
Crop Manual; More Info for Farmers: Soil Fertility Practices; 100
Member CSA plans: CSA Share List, Greenhouse Plan, Field Plan.
https://weatherspark.com/ Weather records for your area. Fun!
Soil temperatures www.greencastonline.com/tools/soil-temperature

Resources – Asian Greens (Sept 2022)
 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,
 Asian Vegetables, Sally Cunningham, Chelsea Green
 The Chinese Kitchen Garden, Wendy Kiang-Spray, 2017, Workman Pubs
 Kitazawa Seeds https://kitazawaseed.com/ has many choices.
 Evergreen Seeds clickable list: https://www.evergreenseeds.com/chinese-
vegetables/
 Fedco Seeds fedcoseeds.com/ & Johnny’s johnnyseeds.com/ have a range.
 Wild Garden Seed has many interesting home-bred varieties. Search under
Mustard. wildgardenseed.com
 U of Ca Agriculture & Natural Resources Asian Vegetable Primer
 U of KY Center for Crop Diversification Ethnic Vegetables: Asian
 Purdue U HO-187-W Chinese Vegetables

Resources - High Tunnels (Sept 2022)
 University of Minnesota Deep Winter Greenhouse extension.umn.edu/growing-
systems/deep-winter-greenhouses
 U of MN High Tunnel Production Manual www.extension.umn.edu/garden/fruit-
vegetable/#high-tunnel
 Cold-Climate Greenhouse Resource https://www.plantgrower.org/uploads/
 6/5/5/4/65545169/cold-climate-greenhouse-resource.pdf
 The Northlands Winter Greenhouse Manual, Carol Ford & Chuck Waibe $20
https://www.farrms.org/product-page/the-northland-winter-greenhouse-manual
HighTunnels.org: hightunnels.org/for-growers/
 High Tunnel Production Manual. 2011. Center for Plasticulture, Department of
Horticulture, College of Agricultural Sciences, The Pennsylvania State University.
$25.00 from Dr. Lamont, e-mail: wlamont@psu.edu
 High Tunnels: Using Low Cost Technology to Increase Yields, Improve Quality, and
Extend the Growing Season by Ted Blomgren, Tracy Frisch and Steve Moore.
University of Vermont Center for Sustainable Agriculture.
https://www.sare.org/resources/high-tunnels/
 High Tunnel Winter Cropping Systems, Lewis Jett, SARE. 2011 Slideshow and audio.
https://northeast.sare.org/resources/high-tunnel-winter-cropping-systems/

Resources - Season Extension - Sep 2022
 Extending the Season: Six Strategies for Improving Cash Flow Year-
Round on the Market Farm Lynn Byczynski
https://www.growingformarket.com/articles/Extending-the-Season-2
 Janet Bachmann, Season Extension Techniques for Market Gardeners,
ATTRA, 2005. https://attra.ncat.org/publication/season-extension-
techniques-for-market-gardeners/
 Fall and Winter Gardening Quick Reference, Southern Exposure Seed
Exchange, https://www.southernexposure.com/growing-guides/fall-
winter-quick-guide.pdf
 Johnny’s Seeds Growers’ Library, Winter Growing Guide:
https://www.johnnyseeds.com/growers-library/methods-tools-
supplies/winter-growing-season-extension/winter-growing-
guide.html
 Johnnyseeds.com. Growers’ Library, High Tunnel Scheduling Guide:
https://www.johnnyseeds.com/growers-library/vegetables/winter-
growing-guide-high-tunnel-scheduling.html.

Resources – More Detail (Sept 2022)
ATTRA Cole Crops and Other Brassicas: Organic Production
https://attra.ncat.org/htmlpub/cole-crops-and-other-
brassicas-organic-production/
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
.aspx. Search Brassica rapa, for example
vegvariety.cce.cornell.edu/main/showVarieties.php Search
for “Mustard”
Sustainable Market Farming, Pam Dawling, New Society
The Year-Round Hoophouse, Pam Dawling, New Society

Resources – books (Sept 2022)
 The Market Gardener, Jean-Martin Fortier, New Society Publishers
 The Complete Know and Grow Vegetables, J K A Bleasdale, P J Salter et al.
Buy used – out of print.
 Knott’s Handbook for Vegetable Growers, Maynard and Hochmuth The
2012, 5th edition is online: https://rockymountainseeds.org/wp-
content/uploads/2020/03/KnottsHandbook2012.pdf
 The Organic Farmer’s Business Handbook, Richard Wiswall, Chelsea Green
 Sustainable Vegetable Production from Start-up to Market, Vern Grubinger,
https://scholarworks.uvm.edu/extfac/17/ NRAES
 The New Organic Grower and The Winter Harvest Manual, Eliot Coleman,
 Crop Planning for Organic Vegetable Growers, Daniel Brisebois and Frédéric
Thériault (Canadian Organic Growers https://www.cog.ca/ )
 The Chinese Greenhouse: Design and Build a Low-Cost, Passive Solar
Greenhouse, Dan Chiras, New Society Publishers.
https://newsociety.com/books/c/the-chinese-
greenhouse?sitedomain=us&undefined Solar-heated, earth-sheltered, well-
insulated, plastic-glazed structures to grow warm weather crops in winter.

Resources – My Slideshows
www.slideshare.net/ Search for Pam Dawling. You’ll find:
 Cold-hardy Winter Vegetables
 Cover Crops for Vegetable Growers
 Crop Planning for Sustainable
Vegetable Production
 Crop Rotations for Vegetables and
Cover Crops
 Diversify your Vegetable Crops
 Fall and Winter Hoophouse
 Fall Vegetable Production
 Feeding the Soil
 Growing Great Garlic
 Growing Sweet Potatoes from Start to
Finish
 Hoophouse Production of Cool Season
Crops
 Lettuce Year Round
 Many Crops, Many Plantings, to
Maximize High Tunnel Efficiency
 Producing Asian Greens
 Production of Late Fall, Winter and
Early Spring Vegetable Crops
 Season Extension
 Sequential Planting of Cool Season
Crops in a High Tunnel
 Spring and Summer High Tunnels
 Storage Vegetables
 Succession Planting for Continuous
Vegetable Harvests
 Sustainable Farming Practices.
 The Seed Garden
 Year Round Vegetable Production
 Year Round Hoophouse Vegetables

Asian Greens in the Winter Hoophouse 75 min 2022.pdf

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Asian Greens in the Winter Hoophouse 75 min 2022.pdf