Adzuki Bean

Compared to other beans, adzuki beans have a slightly sweet flavor. The plant grows 1 to 2 feet high with leaves resembling those of Southern peas. The plant yields yellow flowers that are followed by a cluster of smooth, short, cylindrical pods containing seeds two to three times larger than mung beans. The seeds are primarily dark red, but can include green, straw-colored, black-orange, and mottled seeds. The seeds are round with a protruding ridge (seed scar) on the side.  

Other names. Azuki (Japanese).  

Market information  

Marketing. According to L. L. Hardman, et. al., adzuki markets, as well as product use, are limited. Acreage is contracted in advance of planting. New domestic and overseas markets are currently being developed.  

Current production and yield. Adzuki beans originated in Japan and China, where they are still a major crop. Currently, erect plant types are grown in northern Japan. Branching, vining types do well in China, Manchuria, and other warm climates. Cultivation also occurs in Korea, New Zealand, India, Taiwan, Thailand, and the Philippines. In the United States, adzuki beans have been grown in Florida, Minnesota, and California. Yields are the highest in lighter soils with irrigation and good drainage. Research plots in Minnesota have yielded an average of 1400 lb/acre.  

Use. In Japan, adzuki beans are the second most important dry bean crop, where they are cooked with rice or used in confections. Adzuki bean sprouts are the major product in the United States. Young tender pods can be harvested as snap beans. The pod is eaten like snow peas or cooked like common green beans. Dried adzuki beans require one hour of soaking before boiling. Puréed adzuki beans is made by mixing the mature, dried beans with minced garlic, a pinch of tumeric or chinese mustard, and some grated ginger. It serves as a hot vegetable, is mixed in sour cream or yogurt, used as a salad spread, or as a stuffing in mushroom caps. "An"-- a mixture of adzukis, sugar, and water-- serves as a filling for bread, steamed breads or dumplings, and sweet cakes. The beans are high in protein (25%) and easy to digest.  

Culture  

Climatic requirements. Seeds do well during frost-free periods, with cool nights. The plant is reported to be somewhat drought resistant. Adzuki beans have similar requirements to soybeans or drybeans.  

Propagation and care. Adzuki is a short-day plant that does not grow well in waterlogged soil. Information from the University of Minnesota recommends treating the seeds for fungi, insects and bacteria before planting. Adzuki beans emerge more slowly when the soil is 50 to 55°F. In Minnesota, the best planting time is between May and June. A good plant population is 105,000 plants per acre (25-35 pounds of seed). Plant seeds in rich, loamy soil, F(1,2) to 1 inch deep. Plants should stand 2 to 3 inches apart. Recommended row spacing varies from 12 to 18 inches, or 18 to 30 inches. Neutral to alkaline soil is required for maximum N fixation, and a medium to high soil test level of P and K should ensure adequate fertility levels and the best crop yield. Fertilize seedlings when they are 4 to 5 inches high and again when the flowers start to form pods. Moisture should be ample and at a consistent level. Uneven ripening is characteristic of adzuki beans. Expect mature pods, brownish in color, with slightly yellow and completely green pods on the same plant. Adzuki beans will fix nitrogen but require innoculation with a Rhizobium strain specific to this crop.

White mold, bacterial stem rot, and other bean diseases may affect adzuki beans. A good rotation program, furrow rather than overhead irrigation, use of disease-free seed and a spray program can help prevent these diseases. Most adzuki varieties are susceptible to a number of aphid borne viruses that attack legumes, including curly top virus.  

Harvest and postharvest practices. To harvest as green beans, pick the adzuki pods when the beans are faintly outlined in the pod. Picking every 5 to 6 days is usually sufficient. In California Adzuki beans will mature in less thatn 120 days for use as dry beans.  

Growers can cut and windrow adzukis in the morning to allow drydown and combine later in the day, or direct combine the beans with a grain header or row crop headers. Pods shatter very easily, especially if the harvest is delayed until late in the season or the day. To decrease losses, use slower speeds, open the concaves, and harvest only during appropriate hours. The entire plant, including dry pods, can be harvested and stacked in a dry, well-ventilated place for drying. Complete drying occurs a week or two after harvesting. After drying, shell the beans and store in refrigerated, air-tight containers.  

Pest and weed problems. Adzuki beans compete poorly against weeds. Seed quality is critical to early vigor. Choose a location with light weed pressure and rotary hoe 7 to 10 days after planting. Cultivate the beans when the primary leaves are fully developed, and if necessary, 10 to 20 days later.  

Sources  

Seed:

Dr. Yoo Farm, P.O. Box 290, College Park, MD 20740.

Hudson Seedsman, P.O. Box 1058, Redwood City, CA 94064.

Johnny's Selected Seeds, 305 Foss Hill Road, Albion, ME 04910.

Mellinger's Inc., 2340 S. Range Road, North Lima, OH 44452.

Redwood City Seed Co., P.O. Box 361, Redwood City, CA 94064.

Southern Exposure Seed Exchange, P.O. Box 158, North Garden, VA 22959.

Sunrise Enterprises, P.O. Box 10058, Elmwood, CT 06110.

Vermont Bean Seed Co., Garden Lane, Fair Haven, VT 05743.  

More information:

Breene, William M., and Leland L. Hardman. "Anatomy of a Specialty Crop - The Adzuki Bean Experience." Grain Legumes as Alternative Crops, The Center for Alternative Crops and Products, Univ. of Minnesota. 1987. pp. 67-76.

Hardman, L. L., E. S. Oplinger, J.D. Doll, and S. M. Combs. "Adzuki Bean." Alternative Field Crops Manual. Departments of Agronomy and Soil Science, Cooperative Extension Service and College of Agricultural and Life Sciences, University of Wisconsin, Madison, WI 53706. Nov. 1989. 3 pp.

Harrington, Geri. Grow Your Own Chinese Vegetables. Garden Way Publishing. Pownal, Vermont. 1978. 268 pp.

Robinson, R.G. "Registration of Minoka Adzuki Bean (Reg. No. 19)." Crop Science. Crop Science Society of America. Madison, WI. July/Aug 1980 v. 20(4) p. 549.

Stephens, James. Minor Vegetables. Univ of Florida Cooperative Extension Bulletin SP-40. June 1988, 123 pp.

Whealy, Kent. Garden Seed Inventory: Second Edition. Seed Saver Publications. Decorah, Iowa. 1988. 422 pp.

Yamaguchi, Mas. World Vegetables. AVI Publishing Company, Inc. Westport, Conn. 1983. 415 pp.  

Compiled by Tonya Nelson, Small Farm Center, UC Davis.  

Reviewed by Arthur McCain, 8/2/90.

Reviewed by Steve Temple, 10/91.

Reviewed by Mike Kawate, 10/91.

11/16/91