About Wisconsin Ginseng
Major Uses For Ginseng:
In the Far East, ginseng root is used in toothpaste, soft drinks, tea, candy, chewing gum and cigarettes. It also appears on the market as crystals, extract, powder capsules and is sold as the whole root. In the United States, ginseng and ginseng products are marketed in Asian food and health food stores. Most of the ginseng used in the United States, however, is imported from Korea. The amount of Asian ginseng that is imported is about equal to the amount of higher-priced American ginseng that is exported.
Ginseng seed is also marketed. Ginseng plants generally begin to produce harvestable seed in the third year of growth. It takes approximately 200 plants to produce 1 lb of seed, which may produce 5,000 seedlings.
How It Grows:
American ginseng plants are generally started from seeds. Seedlings or roots for transplanting are available commercially, but are used infrequently. Seeds are planted in the fall and germinate in the spring. Although researchers have examined ways to break this juvenility requirement and hasten germination, it is still not understood.
First-year seedlings produce one compound leaf with three leaflets. This leaf, 1 to 2 in. in height and spread, is the only above-ground growth in the first year. Underground, the plant develops a thickened root about 1 in. long and up to 1/4 in. wide. At the top of the root, a small rhizome or "neck" develops with a regeneration bud at the apex of the rhizome. In autumn, the leaf drops, and a stem supporting new leaves emerges from the regeneration bud the following spring.
The plant develops more leaves, with more leaflets, each year until the fourth or fifth year. A mature plant is 12 to 24 in. tall and has 3 or more leaves, each consisting of 5 ovate leaflets. Leaflets are approximately 5 in. long and oval-shaped with serrated edges. In midsummer, the plant produces inconspicuous greenish-yellow clustered flowers. The mature fruit is a pea-sized crimson berry, generally containing 2 wrinkled seeds.
After three years of growth, the roots begin to attain a marketable size (3 to 8 in. long by 1/4 to 1 in. thick) and weight (1 oz). In older plants, the root is usually forked. Wild or high-quality cultivated ginseng root has prominent circular ridges. Highest quality mature root breaks with a somewhat soft and waxy fracture. Young or undersized roots dry hard and glassy and are less marketable.
Requirements of the Environment:
Ginseng grows best under conditions that simulate its natural habitat. It requires 70% to 90% natural or artificial shade. Ginseng thrives in a climate with 40 to 50 in. of annual precipitation and an average temperature of 50°F. It requires several weeks of cold temperatures for adequate dormancy.
Ginseng generally prefers a loamy, deep (12 in.), well-drained soil with a high organic content and a pH near 5.5. Extremely sandy soil tends to produce long, slender roots of inferior quality.
Seed Preparation and Germination:
Most ginseng crops are started from seed, rather than roots or seedlings. This is the least expensive way to start a plantation and may help prevent the introduction of soil-borne disease to new plantations. Ginseng requires 3 to 5 years to produce a marketable crop from seed.
As there is an 18 month seed dormancy, freshly harvested seed cannot be used for starting a crop. It must be stratified for 18 to 22 months before planting. Seed stratification involves soaking the seed in a formaldehyde solution and in a fungicide, then burying the seed outdoors in moist sand. Most seed is already stratified when it is purchased and needs only to be treated with a fungicide and sown. Seed should not be allowed to dry out before or after seeding. (For detailed instructions on seed stratification, see "American Ginseng Culture in the Arid Climates of British Columbia" by Oliver, Van Lierop and Buonassisi).
For planting seeds or seedlings, till the soil to a depth of 8 to 10 in., and remove rocks. For root planting, work the beds 12 in. deep. For best results, mix soil 1 to 1 with fiber-free woodland soil. Make beds 4 ft wide with alleys between them for walkways and for farm equipment. If the bed is on flat ground, mound the center to facilitate good runoff. Slope the walkways so they will drain water from the beds during heavy rains.
Shade can be provided by wooden lath sheds or polypropylene fabric. Artificial shade should be placed about 7 ft above the ground to ensure good air circulation. Do not use burlap or muslin, which can interfere with air circulation. (For more detailed instructions on how to provide artificial shade, see "American Ginseng Culture in the Arid Climates of British Columbia" by Oliver, Van Lierop and Buonassisi).
Ginseng seed is generally planted in the fall and covered with mulch until spring. It can also be spring-planted, but if seeding is not completed by May 1, the seed may begin to sprout prematurely.
Roots can be transplanted any time after the tops of the plants have begun to die back but before the ground has frozen.
Method and Rate of Seeding:
Plant seedlings 1/8 to 1/2 in. deep and 4 in. apart in the row. Space the rows 6 in. apart across the bed. The recommended seeding rate for a 4 ft wide bed with 2 ft wide paths between beds is 80 to 100 lb/acre. To keep the seed from drying out, the beds should be covered immediately with 2 to 3 in. of straw.
Plant roots at a 30° to 45° angle from the vertical, with the crown of the root 3/4 to 1 in. deep. Cover the bed immediately with 1 to 2 in. of straw. A 4 to 5 in. layer of mulch is necessary on fall transplants to prevent heaving in frost. Some of the mulch can be removed in the spring before the first shoots appear.
Set seedlings 8 in. apart in each direction. Closer spacing tends to increase disease in the plantation.
Light mulching (1 to 2 in. thick) to retain moisture during dry weather is advisable.
Fertility and Lime Requirements:
Heavy use of manure or commercial fertilizers lessens the resemblance of cultivated ginseng to the wild root and hence may reduce marketability. Over-manuring may also force growth and lower disease resistance. Although little research in ginseng fertility has been conducted, common practice has been to fertilize as for other root crops. Recommended rates are about 15 lb P2O5/acre and 60 lb K2O/acre for soils testing in the optimum range for vegetables (30 to 45 ppm Bray P1 and 140 to 200 ppm soil test K).
Nitrogen needs range from 20 to 60 lb/acre, depending on soil organic matter level. (However, some growers have been known to use considerably more.) Growers have tended to use lower-salt fertilizers, such as ammonium sulfate, potassium sulfate and potassium-magnesium sulfate. Although secondary and/or micronutrients are often involved in fertilization programs, little research has been conducted to confirm responsiveness.
Some growers fertilize with leaves or old hardwood sawdust or with ground-up rotted hardwood. Others prefer woodland soil or rotted leaves 4 to 6 in. deep, spaded to a depth of about 8 in. with fine raw bonemeal (1 lb/sq. yd.) worked in.
Fertilizers should be applied during the dormant season at least a couple of weeks before plants emerge.
Although no improved varieties have been developed, American ginseng shows variations in certain characteristics, particularly in the roots. Plants from the northern part of the country, particularly Wisconsin and New York, are considered good breeding stock, because they furnish roots of good size, weight and shape.
Weeds can be controlled mechanically with mulching and hand weeding and chemically with Fusilade 2000.
Diseases and Their Control:
Ginseng is susceptible to a number of fungal diseases, including Alternaria leaf and stem blight, Phytophthora root rot and foliar blight, seedling damping-off caused by Pythium and Rhizoctonia, rusty root and root knot nematode. Ginseng gardens that are cultivated in the woods may suffer less from diseases than do plantings under artificial shade.
To minimize disease problems, select a growing site with good drainage. Good air circulation is also crucial and can be attained by providing cleared areas (walkways) around the beds, relatively uncrowded spacing and control of weeds. Thin spacing also reduces the likelihood of disease spread through foliar or root contact. Wisconsin growers generally do not reuse a ginseng field for succeeding ginseng crops.
Table 1 shows pesticides labelled for nationwide use on ginseng. The University of Wisconsin has obtained approval from the Environmental Protection Agency (EPA) (Sec. 18 and Sec. 24) for several additional fungicides. Approval is granted for use in Wisconsin only, and use must be reported to the Wisconsin Department of Agriculture. Consult your local County Extension Agent each year to find out which pesticides may be applied to ginseng in your area.
Insects and Other Predators and Their Control:
Ginseng is sometimes attacked by white grubs and wireworms. Voles and field mice may feed on the roots. See Table 1 for recommended pesticides.
In Wisconsin, most growers harvest ginseng the third year after planting from seed. The roots are dug in the fall and vigorously washed to remove surface soil. It is important to handle the roots carefully to keep the branching forks intact and maintain the natural color and circular markings.
Drying and Storage:
Ginseng roots are dried on wire-netting shelves in a heated, well-ventilated room. Since overheating destroys color and texture, begin drying the roots at a temperature between 60deg and 80°F for the first few days, then gradually increase it to about 90°F for three to six weeks. Turn the drying roots frequently. Store the roots in a dry, airy, rodent-proof container just above freezing.