Ginseng Production in Ontario
OMAFRA Ginseng Series

Table of Contents

1. Introduction
2. History
3. The Plant
4. Site Selection
5. Garden Preparation
6. Climate Modification
7. Seed Handling and Seeding
8. Production Challenges
9. Root Harvest and Handling
10. Related Links

Introduction

Ginseng is a slow-growing herbaceous perennial. It is a medicinal herb cultivated for its highly valued root in various temperate climate zones, particularly North America and Asia. Panax quinquefolius is the species cultivated in North America. Botanically, it differs slightly from the principle species native to Asia, Panax ginseng. Other species of ginseng are cultivated to a lesser extent.

Ginseng is a member of the Araliaceae family of plants. This family includes wild sarsaparilla, dwarf ginseng and spikenard. All of these plants can be found in the forests of Ontario. The climate and soils of South Central Ontario are ideally suited to the production of ginseng.

About 85 percent of the root grown in North America is sold to the Asian market. In this market, there is a considerable distinction between North American ginseng and Chinese ginseng based on its medicinal uses.

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History

Ginseng has a special place in the history of Ontario and Quebec. Roots were used in traditional Native medicines. In 1715, a Jesuit priest recognized the plant from descriptions out of China and initiated export to Hong Kong. At one time, ginseng trade rivalled the fur trade. All of the roots were harvested from the forests. Due to the extent of this harvest, truly wild ginseng is now rare in Ontario and Quebec. Ginseng is now considered a threatened species.

Under the Convention on International Trade in Endangered Species (CITES), a permit is required for export of ginseng. This permit is necessary for wild and field cultivated roots but not for processed root. Ginseng was first cultivated in Ontario in the field under artificial shade in the late 1800's near Waterford, Ontario. It wasn't until after the second world war that the ginseng industry began to expand. Until the 1980's there was a limited number of growers in Ontario. Since that time, acreage has increased and there are now over 300 producers of this herb and over 4,000 acres under cultivation.

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The Plant

Ginseng develops from seed which is planted in the fall. It is an herbaceous perennial and each autumn the stem and leaves fall off the plant. In the spring, around mother's day, a single shoot emerges. This cycle continues until the root is harvested. Under field cultivation, the root is harvested 3 - 5 years after seeding.

In it's first year, the ginseng plant is small, resembling young poison ivy. It has a single leaf with three leaflets at the top of the stem and is 6 - 10 inches tall. In the second year, a single shoot bears 2 leaves, each with 5 leaflets arranged in the shape of an open hand. In succeeding years, there are 3 - 4 leaves on the plant and occasionally 5. The number of leaves increases each year up to the fourth year. After that time, stems may become thicker but the actual leaf number seldom exceeds four. Plant height is related to age for the first three to four years and ginseng over three years old can reach a height of 1.5 to 2 feet. Under cultivation, ginseng may be taller.

Flower heads develop on a single stalk that arises where the leaves are attached to the stem. The flower head is present at the time of emergence in the spring. Flowering occurs over a period of 3 - 4 weeks in mid summer on plants 3 years and older, and occasionally on 2 year old plants. The flower is an umbel with 30 - 40 blossoms. The flowers open sequentially from the outer edge inward and are self fertile. Pollination can occur between flowers on a single flower head or between flower heads. Pollination is assisted by bees and insects that visit the blossoms

After fertilization, berries form and turn from green to a bright red when ripe. Each berry contains two irregularly shaped seeds each seed being approximately 0.5 cm in diameter and slightly longer than it is wide. At this time the embryo is immature and very small. The seed requires stratification, a series of warm and cold temperatures, before the embryo is large enough to initiate germination. The stratification process takes 16 - 22 months.

Ginseng has a fleshy branching tap root with a rhizome at the crown. It is on this rhizome that the bud that will be next years shoot develops during the summer. This bud remains dormant during the winter months.

Most root growth occurs late in the season. The root of ginseng is also contractile. That is, it shrinks vertically each season. This allows the rhizome, which lengthens every year, to remain under the ground. It also provides the root with concentric "wrinkles" that are desirable in the marketplace.

There are no cultivars of ginseng. Field cultivation was begun by moving wild roots into protected gardens. Further expansion of acreage was achieved by using seeds from domesticated wild roots. There is essentially free movement of seed both inter-Provincially within Canada and Internationally within North America. Selection of superior strains has not been achieved with this process.

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Site Selection

Choosing a good site for the production of ginseng is the most important thing a grower can do to ensure a healthy, high yielding crop. In the wild, ginseng prefers a moist but well-drained site with high organic matter content and a pH between 5.5 and 6.5. To successfully cultivate ginseng in the field these basic factors must be considered.

Soil acidity, or pH, must be addressed before ginseng is seeded. Soil that is too acid can be limed to raise the pH. Private consultants and farm supply outlets can provide prospective growers with soil analysis interpretation and advice with corrective measures. Under acid conditions, below pH 5.5, ginseng appears to be more susceptible to disease and plants are generally unthrifty.

Drainage is also critical to the health of a ginseng garden. Under wet conditions ginseng will become diseased and the roots may rot. Moist but well drained soil can be a challenging goal. While soil moisture is modified by the straw mulch on gardens, the natural capacity of the soil to hold the right amount of moisture while excess water drains away is very important. Drainage is also affected by the subsoil structure and by compaction.

Many growers allow 2 to 3 years to "build up"the soil before seeding a ginseng garden. This can be done with the incorporation of organic matter such as plough-down crops or the addition of composted animal manures. All of these activities affect the availability of nitrogen. Advice in nutrient management is available from private consultants and agribusiness professionals serving the ginseng industry.

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Garden Preparation

Once a site is selected and pH, nutrition and drainage have been addressed, garden preparation can begin. Before seeding, soil should be fumigated to reduce the population of nematodes, weeds and disease organisms. Fumigation is best done 4 to 6 weeks before seeding. Effective fumigation requires that soil be worked to 'seedbed readiness' with a moisture level of approximately 60% field capacity. Four to six weeks after fumigation, when all of the fumigant has dissipated, ginseng can be seeded.

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Climate Modification

Ginseng is native to the floor of the mixed hardwood forests of Eastern North America. It requires only 20% sunlight, and in fact will senesce (age) and die if light intensity exceeds this level for any length of time. The high organic matter content of the forest floor provides a moist, well drained environment. In the wild, ginseng is usually found higher on a slope where good drainage is ensured. These requirements for the growth of ginseng mean that, to be cultivated in the field, the field environment must be modified to resemble its natural preferences.

Climate modification for ginseng involves the formation of raised beds, application of straw mulch or other suitable material and the erection of shade sufficient to filter 70 - 80% of the sunlight.

• Raised Beds:
  Before seeding, raised beds must be formed and groomed. Ginseng is grown in beds raised 9 - 14 inches. The distance from the centre of one bed to the centre of the next is approximately six feet. Each bed is five feet in width with a 1 foot gutter on each side. The raised beds improve drainage.

  When deciding on the direction of a garden, whether rows will go North-South or East-West, the direction of prevailing winds should be considered. It is important to design a garden with good air circulation and surface water drainage in order to keep disease at manageable levels. This is best achieved using the natural flow of wind through a garden and by observing the natural drainage patterns of surface water.

• Mulching:
  After seeding, beds are traditionally covered with 2 - 4 inches of straw mulch. This translates into about 500 small bales to the acre. Half again as much straw is added after the second year. The mulch modifies both soil moisture and soil temperature. In winter, it prevents temperatures from dropping below the freezing point of the roots (around -10^o C) and in summer keeps soil temperatures 5 - 10 degrees C below that of an open grassed area. Mulch also prevents excessive moisture loss from the soil. Soil moisture under mulch can remain near 60% field capacity throughout the season. In very sandy soil, irrigation may be necessary but it is not generally routine.
  
  
• Shade:
  Ginseng must be grown in 70 - 80% shade. Shade structures are erected in the spring of the first year before the ginseng has emerged. Growers can choose from wooden lath shade or polypropylene cloth shade. Shade can be put on wooden or metal posts and can be 8 - 12 feet in height. Costs of erecting a shade structure varies depending on the type of material chosen. Most shade structures cost between $16,000 and $21,000 per acre. Shade is removed wholly or partially each autumn after the plants have senesced and the leaves turn colour and fall, and is replaced again in the spring as plants emerge. Both the wooden lath and cloth are re-usable.

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Seed Handling and Seeding

Seed is produced primarily in gardens 3 years and older. When the berries are ripe and the seed is picked, the ginseng embryo is immature and very small. Before it can germinate, the seed must undergo stratification, a maturation process, that lasts from 16 - 22 months. Seed is harvested by hand and because the seed heads ripen sequentially, seed may need to be picked several times in a single garden.

After picking the berry, pulp must be removed. This is done either by a natural fermentation process or by mechanical depulpers. The depulped "green" seed is then washed and surface-sterilized and mixed with an equal portion of clean, coarse sand. The seed must be kept moist at all times after depulping. In as little as 20 minutes of drying, the embryo will begin to deteriorate and will soon lose the ability to germinate.

The seed/sand mixture is placed in seed boxes and buried in the soil until late the following summer. When seedboxes are dug, the seed is separated from the sand, washed, surface-sterilized and kept moist until planting.

It is important to store stratified seed at acceptable temperatures before planting. Stratified seed should be held between 15 and 20^o C. If it is held at temperatures that are too cool, it becomes dormant and emergence may be reduced. When this happens, many seedlings can emerge in the garden's second year. This means that when the garden is ready to dig, root size will vary considerably. If seed is stored at temperatures that are too high, the seed will decay.

Seed is spread on prepared beds with equipment that ranges from simple seed boxes to sophisticated air seeders. What method is chosen is up to the grower. Custom seeding is frequently offered as a service to growers who choose not to own and operate their own seeding equipment.

Seeding rates vary from 80 to 130 pounds per acre. There are approximately 8,000 ginseng seeds per pound. Higher seeding rates have been viewed as a means of overcoming the poor germination of ginseng. Sixty to seventy percent germination is not uncommon. Higher seeding rates, however, do not necessarily mean better roots and higher returns. Under cultivation, ginseng stands thin naturally by year three to approximately 80 plants per square meter. This final plant density occurs whether ginseng is seeded at 80 pounds or 130 pounds per acre. In the first two years at high seeding rates, the plant stand (the number of plants per square meter) will be proportionally higher at higher seeding rates. Root shape is determined in the first two years of plant life. Research in North Carolina has shown that low seeding rates of 40 lbs/acre can produce roots more than twice as heavy as high seeding rates of 125 lbs/acre. In the same study, the difference in total yield was only 28% more for the denser planting. The value of ginseng roots is afected by it's shape. If long, narrow roots are more than 28% lower in value than chunky root, then the increase in total yield will not offset the lower price of the small roots.

It has become obvious that ginseng cannot be produced organically at any of the common commercial seeding rates. To grow ginseng without the input of disease control chemicals, seeding rates should not exceed 40 pounds per acre and 20 is preferable. Root disease can still occur at these rates but its spread can be better controlled with cultural practices.

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Production Challenges

• Environment:

  Ginseng is highly sensitive to the environmental conditions in which it grows. Both heat and drought adversely affect ginseng. Sites that are too wet invariably suffer from root disease and yields can be drastically reduced. Drought and heat will lead to flower abortion and consequent reduction in seed set. Heat can bring about stress related leaf responses such as papery leaf spot. Lack of soil moisture will lead to reduced root weight. Exposure to direct sunlight will lead to the death of the above ground portions of the plant. Gardens with poor air flow will experience leaf and head blight diseases.

  Outside of the forest, climate modification is the only means of addressing soil moisture and both soil and air temperature.

• Diseases:
  
  

Root diseases limit the yield of ginseng on a world-wide basis. Losses in yield from 30 to 60% are not uncommon. Some root diseases affect root shape and quality. The serious diseases rot the root and completely destroy it. These diseases are caused by fungi that are found in soils throughout the ginseng producing areas of the world.

There are several foliar blights and seed blasting diseases that exert continual pressure on ginseng gardens throughout the season. These diseases may limit seed production and root weight but seldom account for actual root loss as do the root rot diseases. The fungi that cause these diseases are constantly present in air currents. Gardens must be protected on a continual basis from the time they emerge until they begin to senesce.

• Insects:
  Insects in ginseng do not as a rule limit yield or affect root quality. In certain sites, cutworms may be a problem, but those sites usually have a high number of grassy weeds.

  Leaf rollers, usually general forest-feeding species, may invade ginseng gardens. They will forage from rolled leaf "nests" throughout the day. They are usually attracted to older gardens and those near forested areas. Little is know of the effect of these insects on ginseng yield.

  Another invader from the woods is the pit scale. The pit scale has a wide host range and the ginseng family is among its preferred hosts. The scale attaches to the stem and petioles causing them to become distorted and twisted. A plant normally 2 feet tall will twist down to 6 - 8 inches in height. This insect is found infrequently and its affect on the crop is unknown.

• Other Pests:
  Slugs can be a problem in the spring. The straw mulch creates an environment favoured by slugs and they will feed on both shoots and any roots that are close to the soil surface, sometimes causing significant losses. Slug damage occurs most frequently near the garden borders.

  Ginseng is affected by air pollution. It is moderately sensitive to ozone and sensitive to sulphur dioxide. Sulphur dioxide damage appears as bleached areas on the leaf tips or bases. This damage occurs most frequently in the spring.

  Drought and heat will stress ginseng. The tips of leaves and sometimes the interveinal areas will turn papery white or tan. This is referred to as papery leaf spot.

  Mice will occasionally invade a garden. The straw mulch provides protection from natural predators and mice will tunnel along the garden surface under the straw. These rodents will chew off stems and occasionally eat roots at the soil surface. Mice tend to seek shelter in ginseng gardens when the surrounding field crops are harvested in the late summer or fall.

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Root Harvest and Handling

Ginseng is harvested using modified potato diggers. Before roots are dug, the shade structure is removed and the bed surface is scraped clean of straw and plant debris.

After the digger has passed over the garden, roots on the soil surface are removed by hand and placed in bushel baskets. Care must be taken not to bruise or break the root. Several passes over the garden may be necessary to remove all of the root.

Completely automated digging equipment is available for purchase, lease or contract digging.

• Refrigeration:. The washed root is stored under refrigeration for 4 - 6 weeks. This process improves the aesthetic quality of the root and makes it less susceptible to heat damage during the drying process. Before curing, the root is washed in a tumble washer drum to remove excess soil particles
  
  
• Drying:
  
  
  

Ginseng root is usually sold as dried root. It is dried in kilns modified to provide appropriate air flow and temperature. It is placed in shallow trays and the trays are often rotated several times during the drying process. This ensures even drying of a mixture of sizes and shapes. Dryness is determined by how quickly and easily the dried root breaks and by surface texture and resilience.

• Packing: Dried root is packed in cardboard barrels lined with plastic bags in 100 lb lots. The barrels are then sealed and shipped. Ginseng root is not usually graded on the farm. Buyers prefer a consistent mixture of "pencil root" and "chunky root" in all of the barrels but no grading is done beyond that. Further grading of the root takes place in warehouses at the shipping destinations.

  Custom refrigeration and drying is offered by experienced growers with large facilities.

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