OSU Master Gardener and chef says plant Asian greens in mid- to late summer

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Last Updated: 
July 25, 2007

CORVALLIS, Ore. – If you have ever visited an Asian market you may have noticed the bounty of unusual green, leafy vegetables. Most of these greens belong to the mustard family, mostly from the genus Brassica, often termed "Asian brassicas," by vegetable breeders and food aficianados alike.

As a chef, cooking teacher and Oregon State University Master Gardener, Robert Hammond highly recommends growing and cooking Chinese cabbages, Bok Choy, Chinese mustard greens, Mizuna and other Asian brassicas.

"Easy to grow, delicious and nutritious, Asian brassicas can be used raw in a simple salad," said Hammond, who runs a cooking school on his farm in Warren, in Columbia County. "Or try steaming them lightly and then drizzle with a vinaigrette dressing or simply sauté in good olive oil with garlic and a little hot pepper.

"Following Asian culinary traditions, these greens may be stir-fried, used in soups, braised or salt-pickled as westerners would prepare cabbage for sauerkraut."

Experimentation is the best teacher in learning how to grow and prepare Asian greens, explained Hammond.

"Be a little daring and adventurous," he said. "Try something new and different. Enjoy the Choy of growing, cooking and eating Asian greens."

Sow Asian brassica seeds in early spring or late summer, directly into a fertile, well-cultivated seedbed, or plant young transplants. Although some varieties have proven to be heat-resistant (refer to your seed sources), most types grow best in a cool environment in moist, airy and fertile soil. Look for information on the seed packages of the specific greens that you are growing. Most of them prefer cooler weather, so it is best to avoid the heat of mid-summer when planting these greens, or they may bolt (bloom and set seed) prematurely.

"Some varieties are more prone to bolting than others," explained James Myers, OSU Department of Horticulture vegetable breeder, who has grown out many Asian greens at the OSU vegetable research farm in Corvallis. "Carefully read catalog descriptions to determine which varieties would be most suitable for a particular time of year. In my experience, some Bok Choy and Tah Tsai varieties are particularly prone to bolting, even when planted in the fall. These are probably only supposed to be planted after the fall equinox."

Flea beetles and cucumber beetles tend to be the main insect pests. Use floating row covers to protect young crops from pests. Slugs can play havoc on greens especially in the cool wet seasons of spring and fall.

The optimum soil temperature for direct sowing of seed is 40 to 75 degrees. Gardeners should keep the bed uniformly moist until germination. Thin the plants to a distance of six to 12 inches apart, or 12 to 18 inches for Chinese cabbage. Spring crops may be sown as soon as danger of frost has passed and fall crops may be sown from July to mid-August.

For transplants start the plants four to five weeks after the danger of frost for spring planting and early June to mid-July for fall crops. Set out transplants when there are four or five true leaves to a depth of the first pair of leaves following the same spacing guidelines as with direct sowing.

Hammond, who has grown, cooked and eaten many of these greens, describes the major types of Asian brassicas:

Chinese cabbages respond well to decreasing temperatures and day length making this a good crop for fall. They include small loose leaf types such as Pei Tsai, semi-heading types and heading types such as Napa and Wombok.

Pak Choy, also known as Pac Choi or Bok Choy, include the small loose-leaf greens that are the most popular vegetable grown and sold in markets on the West Coast. Also called baby Bok Choy, Shanghai Bok Choy, Ching-Chiang Choy, or Ching-Kung Choy, they are fast-growing with tender green leaves and crisp petioles. Many varieties are adapted to different climates and seasons. There is also the large leaf type with glossy, dark green leaves with long, large white petioles; it grows best in mild and slightly cold climates and is suitable for early spring and fall crops. It may bolt in hot weather.

Tah Tsai (Tat soi) forms a rosette of spoon-shaped dark green leaves. This type is low to the ground and rather slow growing.

Gai Lan (Chinese broccoli, Chinese kale) has glossy blue-green leaves with crisp thick stems. It adapts well to cold and hot climates; after the first cutting of the main stem, the plant will grow many branches for succulent harvest.

Chinese mustard (Mustard cabbage, Gai Choy) is resistant to low temperatures and grow best in temperate cool climates. Some kinds are leafy and others form heads or semi-heads in cold climates; these have a mild flavor that increases in pungency as the plant matures. Heading types include Bau-Siu and San-Ho Gent. Leafy varieties include Broad leaf, Miiki Purple Giant and Japanese Red Giant.

Komatsuna (Japanese Mustard Spinach) is neither a mustard or a spinach; the young leaves, stalks and flower shoots are eaten; it is fast growing so may be grown year-round in mild climates; it is ready for harvest in 35 days when sown in warm climate.

Yu Choy, also known as edible rape or green Choy Sum, is different from the oil seed rape grown in the West; it is mainly grown for harvesting young leaves and flowering stalks; plants are harvested when bolting (blooming); fast growing.

White Choy Sum is similar to the large white petiole type of Pak Choy, but features more tender and delicious stems and flower buds; dwarf varieties are often called baby Bok Choy.

Mizuna greens have long slender white stalks and feathery dark green leaves; these are tolerant to both hot and cold weather conditions and can be grown year round. They are vigorous and can be harvested as cut-and-come again.

Mibuna is a Japanese green, similar to Mizuna but with a stronger flavor. It has dark green narrow strap leaves. Vigorous and easy to grow, Mibuna withstands cold very well so it is suited for fall and winter.

Chinese flower cabbage (Naban) is a type of flowering Chinese cabbage with crinkled or "savoy" leaves. The young stalks and flower buds are traditionally eaten. These grow well in mild climates and can be harvested 40 days after sowing.

Leaf radish (Lo Bok, Daikon) is grown exclusively for the greens; these plants are fast growing and prefer cool weather.

Seed sources for Asian greens include: http://www.evergreenseed.com, http://www.newdimensionseed.com, http://www.kitazawaseed.com

To learn more about how to cook Asian greens and download recipes, visit Hammond's cooking school website at: http://www.honeymancreekfarm.com

Author: Carol Savonen
Source: Robert Hammond, James Myers