From: Brian Lo Newsgroups: rec.gardens Subject: FAQ: Oriental Vegetables 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. ___________________________________________________