Download - Producing Asian greens 2015 Pam Dawling
Producing Asian Greens©Pam Dawling 2017
Twin Oaks Community, Central Virginia
Author of Sustainable Market FarmingPublished by New Society Publishers
SustainableMarketFarming.com
facebook.com/SustainableMarketFarming
Outline1. Meet the Asian Greens
2. Crops I recommend for easy success
3. Crops to try later
4. Crop requirements
5. Pests and diseases
6. Growing in spring
7. Growing outdoors in fall
8. Growing in the winter hoophouse
9. Harvesting
10.Minimizing nitrate accumulation in winter
11.Seed saving• Pak Choy. Credit Ethan Hirsh
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 hereCredit Ethan Hirsh
Advantages A quick way to fill out your
market booth or CSA bags A catch crop for spaces where
other crops have failed or otherwise finished early. Keep a flat of seedlings ready, pop plugs into any empty spaces
Better able to germinate in hot weather than lettuce
Faster growing than lettuce Faster-growing types are
ready for transplanting 2 weeks after sowing (or you can direct sow)
Trial many kinds, use unwanted seed in baby salad mix!
Our hoophouse in NovemberPhoto 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
Who’s Who – 3 main groups1) The turnip family, Brassica rapa,
of Asian origin
a. Some crops are Brassica rapa var. pekinensis (napa cabbage, michihli, celery cabbage);
b. Others are B. rapa var. chinensis(bok choy),
c. B. rapa var. japonica (mizuna),
d. B. rapa var. narinosa (tatsoi),
e. B. rapa var. perviridis (komatsuna)
Different sources use different names
2) The cabbage family, B. oleracea, of European origin
Kai-lan, Chinese kale
3) The Chinese Mustard family, B. juncea
Ruby Streaks (shown here, Photo Johnnys Seeds),
Golden Frill, Red Rain
If you plan to grow seed of more than one Asian green, carefully choose ones that won’t cross. Be aware of the possibility of brassica crops being wrongly classified
2. Crops I recommend1a. Brassica rapa var. pekinensis
Wong Bok types
• Napa cabbage is a Che-foo type of wong bok,
• Cylindrical cabbages such as Michihli (below) and Jade Pagoda are Chihli types of wongbok
• Photo Southern Exposure Seed Exchange
Celery cabbage types• Loose-leaf, non-heading, fast-
growing vegetables with light green leaves and white petioles. Maruba Santoh and Tokyo Bekana (below)
• Photo Johnnys Seeds
1a. Brassica rapa var. pekinensis.
Napa cabbage
Photo Kashruth Council of Canada
• A type of wong bok• Very tender, light green leaves• Excellent for stir-fries, pickling • Hardy to about 25°F (–4°C)• We like Blues (52 days from
seed to harvest) best • Kasumi has the best bolt
tolerance and is larger: 5 lb (2.3 kg) compared to 4 lb (1.8 kg)
• Orange Queen is a colorful but slower-growing variety (80 days)
• All are hardy to about 25°F (–4°C)
• Stores better than michihli types
1a. Brassica rapa var. pekinensis
Michihli (Cylindrical Wong Bok) Chinese cabbage
• Produces 16" (40-cm) tall heads 6" (15 cm) across.
• Produces more in the same space compared to Napa cabbage
• Very tender, light green leaves• Excellent for stir-fries and
pickling. • More stress tolerant and
resistant to bolting and black speck than Napa cabbage
• Cannot be stored as long.• We like Jade Pagoda (72 days)
and the O-P Michihli (72 days)• Photo Southern Exposure Seed Exchange
1a Brassica rapa var. pekinensis
Celery cabbage (pe tsai)Photo credit Johnnys Seeds
The second type of B. rapa:• A fast-growing, looseleaf,
non-heading vegetable with light green leaves and white petioles.
• Mild flavor, tender texture: can be substituted for lettuce
• Can be ready for harvest in 3–4 weeks after sowing.
• More heat tolerant than Napa. Cold tolerant to 25°F (-4°C)
• Fairly bolt resistant• Maruba Santoh, Tokyo
bekana – very similar
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
1a or b Brassica rapa var. pekinensis or var. chinensis
Tokyo Bekana• Fast-growing tender
chartreuse frilly, leafy plant.
• 21 days to baby crop, 45 days to full maturity
• Can be used for salad leaves during late-summer lettuce shortages.
• Mild flavor - many people don’t even notice they are not eating lettuce!
Young Tokyo Bekana seedlings in our November hoophouse.
Photo Ethan Hirsh
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 choyRed 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
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 Seedshttp://www.kitazawaseed.com/seed_369-77.html
1e. Brassica rapa var. perviridis or Brassica rapa var. komatsuna
Komatsuna• Also known as mustard spinach
(so is Pak Choy!), Summer Fest
• Green or red (purple)
• Baby salad size in 21 days, full size in 35 days
• A large plant 18" (45 cm) tall
• Pick and bunch individual leaves
• Or harvest the whole plant
• The flavor is mildly peppery
• Cold-tolerant to 15°F (-9.5°C), perhaps 10°F (-12°C)
Photo credit Fothergill Seeds
Photo Fothergill Seeds
1. Brassica rapa or 3. juncea
Yukina Savoy• like a bigger tatsoi,
• blistered dark green leaves and stems
• delicious flavor
• about 12" (30 cm) tall
• Tolerant to heat and cold –down to 10°F (-12°C)
• Transplant at 12" (30 cm)
• 21 days to reach baby size, 45 days to full size
Photo Ethan Hirsh
Yukina SavoyOutdoors in December, after several nights at
16-17°F (-8 to -9°C)
Hybrid of 1e. Brassica rapa var perviridis& 2. Brassica oleracea
Senposai - Our star of Asian greens • A cross between
komatsuna and regular cabbage.
• A big plant producing large, round, mid-green leaves which are usually harvested leaf by leaf.
• Cooks quickly (much quicker than collards)
• Delicious sweet cabbageyflavor, 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
3. Brassica juncea
Red Splendor, Ruby Streaks, Golden Frill
Johnny’s Red Splendor Ruby Streaks Photo Southern Exposure Seed Exchange
Golden Frill http://www.evergreenseeds.com
Asian-type brassica salad mixesWild 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.
Pseudo-Asian GreensPink Lettucy Mustard, Brassica rapa japonica, Mild-flavored at all growth stagesPhoto Wild Garden Seeds
Ornamental and garnish kales and cabbages add color and texture. We like Nagoya Red and White and Red ChidoriPhoto http://www.extension.iastate.edu
3. Crops to try laterSmall 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
Crops to try laterBig and sturdy greens
Tyfon Holland Greens - a strong plant, a hybrid of komatsunawith 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.
Tenderleaf – a big, sturdy, OP plant. Quick-cooking, mild-flavored, despite appearances. Selected from a cross of Tendergreen and tatsoi. Very disease-resistant and cold tolerant down to 20°F (-7°C). Can be sown later in the fall than other greens - could be the solution if your original plan didn’t work. Can be a useful salad mix crop at the baby stage.
Chinese Thick-Stem Mustard. Photo Southern Exposure Seed Exchange
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 yakattanaPhotos: left http://www.truffulaseedproduce.com, right http://tanicreekfarm.com
Photo Kitazawa Seeds http://www.kitazawaseed.com/seed_051-68.html
• Transplants of Red Giant MustardPhoto Southern Exposure Seed Exchange
• Mature Red Giant Mustard
Mustard greensMustards such as Red Giant, Osaka Purple, Brassica juncea, and American Mustards (eg Southern Green Wave) proved too hot for salads for us, even at 3" (8 cm) leaves. Best cooked. Hardy to light frosts. Attractive colors. 21 days to baby leaves, 40–45 days full size
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 greensSimilar care requirements to other brassicas,
Shallow rooted - Pay extra attention to providing enough water during hot weather to prevent bitter flavors and excess pungency,
Do close monitoring of pests, which can build up large populations during the summer.
Very fertile soils grow the best Asian greens,
Turn in leguminous cover crops
or compost to
provide adequate nutrition.
Sow or Transplant?
We almost always transplant brassicas because we use our growing spaces very intensively.
Transplanting gives the previous crop extra time.
If we have 4 weeks between the end of one crop and transplants going in, we sow buckwheat to add organic matter and smother weeds.
We grow a lot of brassicas and our crop rotation is always pushed and stretched by the amount of brassicas we’d like to plant – transplanting allows the soil extra weeks without brassicas.
Transplanting for fall crops In summer, the faster growing types
(Napa cabbage, Tokyo Bekana and Maruba Santoh) are ready to plant out 2 weeks after sowing..
Most others transplant best at 3–4 weeks of age (less time than needed in spring). We transplant outdoors July 10 - July 31 for early fall crops. Later is possible.
To minimize transplant shock, water the plants well an hour before transplanting, get them in the ground as quickly as possible and water again.
Shadecloth or rowcover will help keep the breezes (if any!) and strong sun off the plants.
Maruba Santoh transplant. Photo Ethan Hirsh
Irrigation Shallow-rooted, need plenty of
water to grow pleasant-tasting leaves.
1” (2.5 cm) of water per week
2” (5 cm) during very hot weather
Drip irrigation saves water, reduces disease and weed pressure
Overhead irrigation can be cheaper and easier to set up for crops that will be harvested before much time has passed.
Overhead sprinklers can wash off aphids - could be all the control you need
Ruby Streaks mustard with drip irrigation.Photo Ethan Hirsh
5. Pests and diseases
ProtekNet on hoops
ProtekNet Pest Control Netting is made of clear high-density polyethylene with UV resistance and a lifespan of eight to ten years. Its light transmission is 90 percent. It is available from Purple Mountain Organics in Maryland. The 1.35 × 1.35 mm 60 gm/m2 mesh is one-sixth the length of a cucumber beetle. It also protects crops against weather damage.
Mesh fabric with small holes is better than rowcover in hot weather - airflow is better and it heats less.
Photo Dubois Agrinovation
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. Insecticidal soaps can be used.
o Caterpillars can be kept off the plants with rowcover or ProtekNet. Bt(Bacillus thuringiensis) will kill caterpillars if rowcovers fail. Btdegrades 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 Cotesiaglomerata
More Pests
Even More Pestso 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.
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
6. Growing in SpringIn 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
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 CropsWe 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
Season extension Fast growing varieties can be
succession sowed for a continuous supply.
Cold-hardy types can be harvested all winter in climates milder than zone 7.
Or they could be kept alive to revive in spring and provide earlier harvests than spring-sown crops.
Wild Garden Seeds and Even’ Star Farm specialize in producing seed for very cold-tolerant varieties.
Rowcovers on hoops will help keep these crops in marketable condition, and improve the microclimate, for better growth rate.
A well used bed of senposai in November. Credit Kathryn Simmons
Cold-Hardiness
32F (0C): Some Pak Choy
25F (-4C): Chinese Napa cabbage, MarubaSantoh, Mizuna, Tokyo Bekana, most Pak Choy
20F (-7C): Tendergreen, Tyfon Holland Greens
15F (-9.5C): perhaps Komatsuna
12F (-11C): Senposai
10F (-12C): Tatsoi, Yukina Savoy, probably Komatsuna
8. Growing in the winter hoophouseHoophouses 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 hoophouseplants 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
Persephone days and scheduling winter hoophouse crops
When the daylight is shorter than 10 hours a day not much growth happens. The dates depend on your latitude.
In Central Virginia, latitude 38° North, this period lasts two months, from November 21 to January 21.
The dates are modified by the time it takes to cool the soil and the air.
The effective dates for us are closer to December 15 -February 15.
To harvest in the darkest days of winter you’ll need to plan a good supply of mature crops to take you through. What has already grown before this period will provide most of your harvests.
Be aware of the increase in days to maturity in winter.
Fall outdoor sowings to transplant inside
• Sept 15: pak choy, Chinese cabbage, Yukina Savoy, Tokyo Bekana, Maruba Santoh,
• Sept 24: Senposai, more Yukina Savoy, mizuna We use hoops and ProtekNet, and water frequently.
ProtekNet and hoops. Photo Wren Vile
Fall Hoophouse Planting - SeptemberEarly September : We clear and
add compost to one of the beds and sow tatsoi.
Sept 15 and Sept 24: We make outdoor sowings of crops to later transplant into the hoophouse at 2- 4 weeks old.
At the end of September we clear summer crops from one more bed, add compost and work it in. We transplant Tokyo Bekana and Maruba Santoh at 2 weeks old, Chinese cabbage, pakchoy, Yukina Savoy at 3 weeks.
Photo November hoophouse beds. Ethan Hirsh
Fall Hoophouse Planting - October Late October we sow more
“filler” Asian greens
In the fourth week of October, we clear and prepare more beds and transplant the Senposai, mizuna, Yukina Savoy at 4 weeks old.
Early October, we sow some “filler” Asian greens, to fill gaps later. We try hard to keep all the space occupied, mostly using Asian greens, lettuce and spinach. Mizuna Photo credit Ethan Hirsh
For more crops, see my slideshow Hoophouse in Fall and Winter on SlideShare.net
Hoophouse Planting –November and December
Nov 10 we sow more mizuna
Nov 11-20 we sow tatsoi
From Nov 10 on we aim to keep a fully planted hoophouse, and as each crop harvest winds down, we immediately replace that crop with another.
During December we use the “Filler” greens plants to replace casualties and heads of Chinese cabbage, Pak choy, YukinaSavoy each day as soon as we’ve harvested them.
Pak Choy replacing Yukina Savoy here. Photo Ethan Hirsh
Hoophouse Planting –December to February
We stop filling gaps with Asian greens (and lettuces) on Jan 25, and fill all gaps after that with spinach transplants, until 2/20. After that we only fill gaps on edges of beds, leave centers free for tomatoes, etc.
After 2/20, we harvest the winter crops from the center rows first, plant the new early summer crops down the center, then harvest the outer rows bit by bit as the new crop needs the space or the light. This overlap allows the new crops to take over gradually.
Our winter and spring crops come to an end in March or early April
“Filler” transplants. Photo Ethan Hirsh
9. Winter Hoophouse Harvest Schedule
Harvest of Asian greens starts in November, with mizuna, tatsoi and baby brassica mix.
From December we also have Tokyo Bekana, MarubaSantoh
The new year starts with Yukina Savoy and the bigger greens, including Senposai, pak choy, Chinese cabbage feed us till mid-March.
Michihli cabbage Photo Southern Exposure Seed Exchange.
Harvesting Some of these greens are
harvested as whole heads; others can be harvested by the leaf and bunched or bagged.
The open rosette types, such as tatsoi or the bigger YukinaSavoy, are usually gathered closed and banded with plant ties or rubber bands.
Most can be grown for baby salad mix. With mizuna we do a “half buzz-cut,” snipping off leaves on one half of the plant an inch (25 mm) above the ground each time we come by.
Tat soi shown here. Photo Ethan Hirsh
After Harvest
After harvest, get the crops into shade and a cooler as soon as you can.
Some of the heading types can be stored in a walk-in cooler for several weeks, almost as long as regular cabbage.
Pak Choy shown herePhoto Ethan Hirsh
10. Minimizing nitrate accumulation in winter
In winter, when light levels are low, beware of high levels of nitrates in leafy greens.
A health hazard — nitrates can be converted in the body into nitrites, which reduce the blood’s capacity to carry oxygen and may be further converted into carcinogenic nitrosamines.
Nitrate accumulation
• Plants make nitrates during the night, and convert them into leaf material during the day. It takes about six hours of sunlight to use up a night’s worth of nitrates. In winter, a small handful of leafy vegetables can exceed the acceptable daily intake level of nitrate for an adult, unless special efforts have been made to reduce the levels.
• Spinach, mustard greens (Asian greens)and collardscontain about twice as much as lettuce; radishes, kale and beets often have two and a half times as much. Turnip greens are especially high, at 3 times lettuce levels.
To keep nitrate levels as low as possible Grow varieties best suited for winter; Avoid fertilizing with blood meal or feather meal; use organic
compost. Ensure soil has sufficient P, K, Mg and Mo Water enough but not excessively; Provide fresh air as soon as temperatures reach 68°F (20°C), so
that carbon dioxide levels are high enough; Harvest after at least four (preferably six) hours of bright sunlight
in winter; Avoid harvesting on very overcast days; Avoid over-mature crops and discard the outer leaves. Harvest
crops a little under-mature, rather than over-mature; Use crops soon after harvest; Refrigerate immediately after harvest, store harvested greens at
temperatures close to freezing; Mix your salads; don’t just eat Asian greens!
11. Seed saving If you plan to grow seed of more than one Asian green, carefully choose
ones that won’t cross. Be aware that crops might be wrongly classified.
Also beware of brassica weeds.
For yourself: at least 600 ft (200 m) isolation from other flowering brassicas.
To sell seed: ¼ mile (400 m) with barriers or ½ mile (800 m) without.
Grow at least 120-300 plants, pull out any atypical ones, let the rest bolt.
Why so many? Brassicas are outbreeding plants and if too few are grown, they are in danger of inbreeding depression (not enough genetic diversity)
Save seed from at least 60 to 75 plants, and preferably 125 to 150.
As the seedpods dry, pull up the plants, and hang them up to finish drying under cover. If you have high humidity, use a fan. Hanging plants inside paper sacks will reduce loss of seeds when the pods shatter.
Stomp on the bags to shatter the pods, and then winnow and screen the seeds. See the Saving Our Seed Project guide (in the Resources section)
Resources• Grow Your Own Chinese Vegetables, Geri Harrington, 1984, Garden Way
Publishing. Includes the names for these crops in different cultures.• Growing Unusual Vegetables, Simon Hickmott, 2006, Eco-Logic books, UK.• Oriental Vegetables: The Complete Guide for the Garden
and Kitchen, Joy Larkham, revised edition 2008, Kodansha, USA• Kitazawa Seeds kitazawaseed.com/ & Evergreen Seeds have the most choices. • Evergreen’s helpful clickable list. evergreenseeds.com/asveglis.html• Fedco Seeds fedcoseeds.com/ and Johnny’s johnnyseeds.com/ have a good
range.• Wild Garden Seed has many interesting home-bred varieties. Search under
Mustard. wildgardenseed.com• Even’ Star Farm Ice-bred Seeds localharvest.org/even-star-organic-farm-M9994• Good Earth Seed Company (Tsang and Ma International)
P.O. Box 5644, Redwood City, California 94063. No English website.• ATTRA Cole Crops and Other Brassicas: Organic Production attra.ncat.org/attra-
pub/summaries/summary.php?pub=27• Saving Our Seed Project carolinafarmstewards.org/wp-
content/uploads/2012/05/BrassicaSeedProductionver1_1.pdf an excellent 24-page guide on organic brassica seed production
Producing Asian Greens©Pam Dawling 2017
Twin Oaks Community, Central Virginia
Author of Sustainable Market FarmingPublished by New Society Publishers
SustainableMarketFarming.com
facebook.com/SustainableMarketFarming