Subject: FAQ: Oriental Vegetables

From: Brian Lo <[email-masked]>
Date: Wed, 1 Mar 1995 14:51:34 -0800

Chinese Cabbage and leafy greens
                                  Brassica species

      A great number of descriptive, ethnic and local terms contribute to
confusion regarding Oriental greens.  In Chinese, the word "tsai" in Mandarin
dialect, and "choy" in Cantonese dialect, simply means "vegetable".  Descrip-
tive prefixes are added for further identification such as Pai-Tsai, which
means white vegetable!  Bok Choy refers to all leaf-heading vegetables!  When
Japanese, Thai, Cambodian or other Oriental names or dialects are used for the
same vegetable, often with only slight variations on the Chinese name, as in
"choi" or "joy", confusion can result!  The names given here are often used in
the Pacific Northwest by growers, brokers and buyers of these vegetables.  

      All of the following have 10 chromosomes and generally intercross.  They
are all considered part of the "Mustard Group", and by some authors are all
subspecies of Brassica campestris.

TYPES AND VARIETIES (approximately 45 days for bunching types, 65-80 days for
large heading types).

Chinese Cabbage (Brassica pekinensis) often referred to as Pe-tsai.  Two major
types exist:

      Chihli (elongated, cylindrical types about 4x18 inches):  Jade Pagoda,
Monument, Michihli, Statue.  See note on bolting below.

      Napa or Won Bok, (short, blunt, barrel shaped, about 5x12 inches):  All
Autumn, China Flash, Nerva, RS-5, all these have season-long adaptability. 
Others:  Nagaoka Early, Early Hybrid G, China Pride, China Doll; Tropical
Delight and Kasumi (for warm areas).  Bolting resistant (see also note under
"temperature" section below): All Autumn, China Flash, Nerva, RS-5, Blues,
Tango, Spring A-1, 50 Days.  For Trial: Spectrum, Harbin, Hopkin.  Winter, and
over winter types:  WR Crusader, WR Green 60, WR 75 Days.  Club root re-
sistant: Chorus. 

OTHER ORIENTAL GREENS

Pak-choi (Brassica chinensis):

      SYNONYMS: Pak Choy, Bok Choy, Bok-choi, Taisai, Celery Mustard or Spoon
Cabbage , sometimes preceded by another proprietary name. These greens have
dark green leaves and may have thick white, or thick light green petioles. 
Most of these are bolting resistant:

      White petiole types:  Pak-Choy White, Taisai, Joi Choi, Prize Choi, Lei
Choi, Canton Pak Choi, Chinese Pak Choi White, Japanese White Celery Mustard,
Gracious, White Light. 

      Green Petiole types:  Pak-Choy Green, Mei Qing Choi, Chinese Pac Choi
Green, Pai-Tsai, Fun-Lee, Ching-Chiang.

      Baby Pak-choi, white petiole:  Dwarf Pak Choi, Canton Pak Choi Dwarf
Type.  Green petiole:  Shanghai. Since these are susceptible to bolting, 
delay field planting till mid May or June (see note on bolting below).  

      Bunching Pak-choi:  When intended for use for "bunching", avoid using
the "open" growth habit varieties such as Canton Pak Choi Dwarf, and evaluate
others for an "upright habit" which would be more suitable for bunching.  For
trial:  Hybrid Joi Choi (white petiole), Hybrid Mei Qing Choi (green petiole),
Hybrid Autumn Poem (latter susceptible to bolting).  For bunching, as for baby
pak choi, open-pollinated varieties should also be tried.

Mustard Spinach, Brassica campestris; bunching greens, dark green leaves with
slender green petioles:  Komatsuna, Okiyo, Green Boy.  See note on bolting
below, and delay planting accordingly.

Mustards, Brassica juncea; usually broad-leaved greens, sometimes red-leaved
with green ribs; green-leaf: Miike Giant, Kai Choi (or Gai Choi), Namfong
Round Leaved, Green Spray, Mizuna, Horned Mustard and Green-In-Snow a winter
hardy type.  Red-leaf: Red Giant.

Tatsoi, Brassica narinosa; a thick-leaved, dark green, flat, compact rosette: 
Tatsoi.

Green Spray, Brassica japonica:  Spherical plants with thin oblong or
serrated leaves with long thin petioles:  Mibuna (oblate leaves); Mizuna
(serrated leaves).

Flowering types:

      Purple-stemmed, B. campestris; tender flower stalks and young leaves
bunched just as flowers begin to open:  Hon Tsai Tai, and Tz-Tsai-Tai. Green-
stemmed, B. campestris:  Tsoi-sim.

      Green-stemmed, B. oleracea, var. alboglabra;  Chinese broccoli, or
Chinese Kale,  a popular bunching green, consisting of tender, thickened,
flower stalks and young leaves, which are harvested when two or three flowers
have opened:  Kailaan, Green Lance Hybrid, Gai Lohn.

SEED COMPANIES

American Takii Inc., 301 Natividad Rd. Salinas, CA 93906
Exotica Seed Co. 8033 Sunset Blvd., Suite 125, West Hollywood, CA 90046
Evergreen Y.H. Enterprises.  POB 17538, Anaheim, CA 92817
Harris Moran Seed Co. 3670 Buffalo Rd. Rochester, NY 14624
Hung Nong Seed Co. 867 Hopkins Rd. Williamsville, NY 14221
Johnny's Selected Seeds, Foss Hill Rd. Albion, ME 04910
Kitazawa Seed Co. 356 W. Taylor Street, San Jose, CA 95110
Kyowa Seed Co. Ltd. 15-13 Nanpeidai Shibuya-Ku, Tokyo, Japan
Known-You Seed Co., Ltd. 26 Chung Cheng 2nd Road, Kaohsiumg, Taiwan ROC
Nichol's Garden Nursery, 1190 North Pacific Highway, Albany, OR 97321
Stokes Seeds Inc. Buffalo, NY 14240-0548.  416/688-4300
Sakata Seed America Inc. POB 877 Morgan Hill, CA 05037
The Good Earth Seed Co./Tsang and Ma, P O Box 5644, Redwood City, CA 94063 
W. Osborne Seed Co. Int'l. 1679 Highway 99 South, Mount Vernon, WA 98273
Zenner Bros. Seed Co., Inc.  1311 S.E. Gideon St. Portland, OR 97202

TEMPERATURE 

      This crop grows best in a cool, moist environment.  Optimum temperature
for growth in the first half of the growth period is about 68 F, and that for
the second half (head formation) is 59 F.  Under high temperature conditions,
the plant grows slowly but it can tolerate temperatures above the optimum if
there is enough soil moisture.  Allthough all are somewhat frost tolerant,
frost injury may occur with some types when the temperature falls from 26 to
18 F.

      Bolting:  Premature seed stalk development (bolting) of Chinese cabbage
and Pak-Choi type greens is a result of vernalization of seedlings by cold
temperatures when planted too early in spring.  Bolting resistant varieties
must be used, or delay planting till late April or May.  Conditions predis-
posing plants to bolting are exposure of seedlings to temperatures of about 40
F for a week, or 50 F for two weeks, or prolonged temperatures below 55 F.  

SEEDING AND SEED TREATMENTS

      Chinese cabbage seed numbers approximately 160,000 per pound.  Seed of
the other Oriental greens mentioned above number between 12,000 and 18,000 per
ounce.  Pelletizing is not necessary with modern vaccuum planters.  Primed and
coated seed is becoming popular.  Consult your seed dealer about the avail-
ability of primed seed.

      Use hot-water treated seed and fungicide treat seed to protect against
several serious seed borne diseases.  Hot water seed treatments are very
specific (122 F exactly, for 25 to 30 minutes; the wet seed then quickly
cooled and dried).  The seed treatments are best done by the seed company, and
can usually be provided upon request.

SOIL

      Chinese cabbage grows well in well-drained fertile sandy loam soils with
good water-holding capacity.  Compost and manure can widen the range of
acceptable soil types by adding organic matter.  A steady supply of water is
required since a shortage will reduce yield and induce tipburn caused by
calcium imbalance. 

PLANTING

Direct-Seeding:

      Spring planting: as early as possible for early summer harvest.  Bolting
tolerant types may be seeded in the field in mid-April, others beginning in
late May.  All may be planted sequentially till mid-August.
      Fall planting: middle of August for October and November harvest.  Sow
the seed directly in rows 2 ft apart and thin seedlings to 12-20 in. between
plants within the row.  Spacings vary with cultivar.  Early maturing types
require less space than the late types, and the Chihli type requires closer
spacing than the Napa type.  Seeds are sown at a rate of 8-10 oz/acre and hand
thinned to one plant per location at the desired spacing.  

      For "baby" and "bunching" pak choi production, high populations (4 x 4
inch spacing) should be used to obtain needed growth habit and adequate
yields.

Transplanting:

      Early spring field seeding may result in a high percentage of flower
stalks.  Therefore to produce a good summer crop, seedlings should be raised
in the greenhouse and transplanted to the field after the risk of cold
induction is minimized.  For a late June and early July harvest, seedlings
with 5-8 fully expanded leaves should be transplanted during May 10-20, and
may be protected with plastic row covers.  Use modular-grown transplants. 
Chinese cabbage is not normally transplanted as a bare-rooted plant.  The
transplant should be set in the soil to a depth of the first pair of leaves.

FERTILIZER

      The following rates are general recommendations for western Oregon.  It
is advisable to do a soil test for each field to be planted.

      Nitrogen: 150-175 (N) lbs./acre.
      Phosphorus: 70-150 (P2 O5) lbs./acre
      Potassium: 130-175 (K 2O) lbs./acre
      Sulfur: 30-50 (S) lbs./acre

      Disk 1/2 of the nitrogen and all the potassium and sulfur fertilizer
into the soil before planting or transplanting, and band the other 1/2 of the
nitrogen at planting or transplanting.

      Note:  Excess nitrogen, and nitrogen applied after head formation can
      result in pepper spot.  This is a physiological disorder that causes
      small black spots on the midribs of head leaves.  Excess magnesium,
      excess manganese, boron deficiency or cauliflower mosaic virus, and
      storage at temperatures above 40 F. may aggravate, or cause similar
      symptoms. 

IRRIGATION

      Irrigate uniformly for vigorous tender growth.  About 10-12 inches of
water may be required depending on planting date, seasonal variation and
variety.  

      Soil type does not affect the amount of total water needed, but does
dictate frequency of water application.  Lighter soils need more frequent
water applications, but less water applied per application.         

HARVESTING AND HANDLING

      Approximate yield of napa Chinese cabbage is 450 cwt./acre.  Pak Choi
yields are approximately 225 cwt./acre.

      Napa and Chihli Chinese cabbage heads are harvested when they reach
appropriate market size (about 3-6 lbs), depending on variety.

      Pak Choi and other greens may be harvested as individual heads similar
to Napa cabbage.  For specialty Oriental markets, these oriental greens are
harvested immature and bunched 6-8 plants per bunch about 40-50 days after
seeding.  The time of harvest depends on one's specific market requirement.

      STORAGE (Quoted from USDA Ag. Handbook #66):

      Store chinese cabbage at a temperature of 32 F. and relative humidity of
95 to 100 %.  Chinese cabbage can be stored 2 to 3 months under these condi-
tions.  Considerable losses are expected after 3 or 4 months of storage at 32
F.  Storage life is shorter at higher temperatures.  A low concentration (1 %)
of oxygen was reported to be beneficial in extending the storage life.  Outer
diseased or injured leaves should be removed before the heads are stored.  The
heads should be packed loosely, and preferably upright, in crates.  Spacing in
storage should allow for air circulation.

      Temperature control in storage of heads with pepper spot is critical as
temperatures above 40 F. aggravate the condition.  Temperatures should be
maintained at 32-34 F. throughout storage and marketing.

PACKAGING

      Chinese cabbage is marketed in wirebound crates of 45-55 lbs., or WGA
crates of 80-85 lbs.

      Pak Choi and other Oriental greens are usually sold as individual heads,
and may be packaged as Chinese cabbage above.  For Oriental markets, bunches
of 6-8 plants each are packaged 24-36 bunches per carton, depending on the
item.  Consult your buyers as to their preference in packaging and containers.

                  PEST CONTROL FOR CHINESE CABBAGE

     THE PESTICIDES LISTED BELOW, TAKEN FROM THE PACIFIC NORTHWEST PEST
CONTROL HANDBOOKS, ARE FOR INFORMATION ONLY, AND ARE REVISED ONLY ANNUALLY. 
BECAUSE OF CONSTANTLY CHANGING LABELS, LAWS, AND REGULATIONS, OREGON STATE
UNIVERSITY CAN ASSUME NO LIABILITY FOR THE CONSEQUENCES OF USE OF CHEMICALS
SUGGESTED HERE.  IN ALL CASES, READ AND FOLLOW THE DIRECTIONS AND PRECAUTION-
ARY STATEMENTS ON THE SPECIFIC PESTICIDE PRODUCT LABEL.

                          USE PESTICIDES SAFELY!

Wear protective clothing and safety devices as recommended on the label. 
Bathe or shower after each use.

Read the pesticide label--even if you've used the pesticide before.  Follow
closely the instructions on the label (and any other directions you have).

Be cautious when you apply pesticides.  Know your legal responsibility as a
pesticide applicator.  You may be liable for injury or damage resulting from
pesticide use.

WEED CONTROL

     Cultivate as often as necessary when weeds are small.  Proper cultiva-
tion, field selection and rotations can reduce or eliminate the need for
chemical weed control.  

     THE WEED TREATMENTS LISTED BELOW ARE TAKEN FROM THE PACIFIC NORTHWEST
WEED CONTROL HANDBOOK, AND ARE FOR INFORMATION ONLY.  CONSULT PRODUCT LABELS
FOR CURRENTLY LEGAL REGISTRATIONS, RATES, AND COMPLETE INSTRUCTIONS.

ACTIVATED CHARCOAL SEED PROTECTION

Several Pacific Northwest grass seed crops are protected from herbicide injury
with the use of activated charcoal which adsorbs and detoxifies or inactivates
the herbicide.  In vegetables, activated charcoal can be mixed with horticul-
tural grade vermiculite and applied as an anticrustant/seed protectant.  The
activated charcoal vermiculite mix is placed within the seed furrow using a
positive feed device.  Herbicides must not leach excessively or move readily
from crop roots into the plant.  Although crop safety can be enhanced, weeds
emerging from within the treated area also are protected.

Another use for activated charcoal involves seed protection from herbicides
that leach into the seed zone from excessive rainfall. Seed coatings of
activated charcoal would reduce the active concentration of herbicide at or
very near the seed during the germination process.

Activated charcoal/vermiculite mix:  

      Thoroughly mix 1 lb activated charcoal/ft3 of number 2 or 3 grade 
      horticultural vermiculite.  If severe dustiness is a problem, add a      
      small amount of water.  Apply 1 ft3 of mixture/600 ft. of seeded row or
      approximately 15 cu.ft/A.  Fill the seed furrow using a positive feed
      applicator and press with a press wheel.
______________________________________________________________________________

WEED MANAGEMENT GENERAL STRATEGY

Weed suppression in crucifers begins by rotating crops that involve different
weed control practices or herbicides to disrupt weed life cycles.  Row
spacings and plant densities vary to achieve head size depending on the market
and to suppress weeds.  Early season weed control comprises application of an
herbicide and/or cultivation(s).
______________________________________________________________________________

STALE SEEDBEDS FOR VEGETABLE PRODUCTION

Stale seedbeds are sometimes used for vegetable production when other selec-
tive weed control practices are limited or unavailable.  The concept depends
on controlling the first flush of emerged weeds before planting or emergence
of the crop followed by minimal soil disturbance which reduces subsequent weed
flushes during establishment of the crop.  Following establishment, other weed
control practices including cultivation or use of other herbicides can be
used.

1.    Prepare a seedbed, preferably 2 to 3 weeks before planting to achieve    
      maximum weed seed germination near the soil surface.  Soil temperatures  
      and moisture must be reasonable or results will be erratic.

2.    Plant the crop with minimum soil disturbance.  Otherwise, new weed seed  
      will be exposed to favorable germinating conditions.

3.    Just before or after planting but before crop emergence, treat the    
      field by flaming or with herbicide to kill all germinated or exposed    
      weeds.

Weed Treatment              Active Ingredient Per Acre and Application Comments
------------------------------------------------------------------------------
Flaming                                      

      Use liquid propane or similar fuel-burning equipment to quickly sear the
      weeds, but not consume them with flame.                         
      ------------------------------------------------------------------------
paraquat                0.625 to 0.94 lb ai/A     
  Gramoxone Extra    

      Restricted-use pesticide.  Do not ingest or inhale spray mist.  Wearing
      protective face shields, respirators, and clothing is advised.  Apply
      during or after planting, but before crop emergence.  Add a nonionic
      surfactant or crop oil concentrate according to label specifications,
      taking care to avoid anionic formulations that react in the tank to form
      insoluble precipitates.  Exposed crop plants will be killed.  Do not
      apply preplant or pre-emergence to soils lacking clay minerals, such as
      peat, muck, pure sand, or artificial planting media.  (Acts as contact; 
      absorbs energy produced by photosynthesis forming peroxides that disrupt
      living cells.) 
______________________________________________________________________________

PREEMERGENCE

Weed Treatment              Active Ingredient Per Acre and Application Comments
------------------------------------------------------------------------------
DCPA                    4.5 to 10.5 lb ai/A                                    
  Dacthal W-75                  
  (Chinese Broccoli
   and Chinese Cabbage)

      Apply at seeding or transplanting.  Can be sprayed directly over
      transplants.  If weeds have emerged, soil should be clean-cultivated or  
      weeded prior to application.  Can be preplant incorporated.  Results are
      improved if rainfall or overhead irrigation occurs immediately after     
      application.
______________________________________________________________________________
______________________________________________________________________________

INSECT CONTROL

     The Pacific Northwest Insect Control Handbook has no control entries for
this crop.  

     Proper rotations and field selection can minimize problems with insects.

DISEASE CONTROL

     The Pacific Northwest Disease Control Handbook has no control entries for
this crop.  

     Proper rotations, field selection, sanitation, spacings, fertilizer and
irrigation practices can reduce the risk of many diseases.  Fields can be
tested for presence of harmful nematodes.  Using seed from reputable sources
reduces risk from "seed born" diseases.

         ___________________________________________________
         ___________________________________________________ 
         This  information was prepared by the Oregon  State 
         University   Extension  Service  from  Oregon   and 
         Pacific  NW publications as well as other vegetable 
         production   guidelines  from  public  institutions 
         in  the  U.S.  and  Canada.  These  guidelines  are 
         intended  as a general guide for Oregon  commercial 
         vegetable producers.  Address comments or questions 
         to  your  County  Extension  Agent  or  Dr.  N.  S. 
         Mansour,  Department of Horticulture,  Oregon State 
         University, Corvallis, OR 9733l. 
         ___________________________________________________