Ginseng (Panax spp)

How well established is this crop?

This is a very new crop to the Otago region. The plants should grow but information on markets, commercial returns, current growers, and any form of regional research may be difficult to find.

Background

Ginseng use can be traced back in China for over 4000 years. One emperor named it the most potent herb known to man. It is known as a tonic and prevents conditions such as poor blood circulation, slow metabolism poor digestion and a lack of vitality.

Ginseng use in the world today is based around two species. Asian ginseng (Panax ginseng) found in parts of Asia; and american ginseng (Panax quinquefolium) found in North America. Another medicinal product named siberian ginseng is also available, but this is from a completely different plant. It does not have the active ingredients ginsenoside and panaxocide, that make true ginsengs useful in herbal medicine.

Ginseng can be grown a number of ways, each resulting in roots that can be sold. The only common factor is the need for shade from the sun. They seem to like a light level of only 15-20% of normal. This plant grows naturally on the forest floor and does not tolerate bright sunlight.

Wild harvested root is the most valuable followed by roots grown in a natural forest environment. The third method of growing ginseng is under artificial shade structures. This is the most common method, but results in the lowest priced root.

Winter Chilling and Frosts

Ginseng over-winters as a root beneath the soil surface. It does not seem to be affected by the cold. Its natural environment in Asia and North America is covered by snow for 2-3 months of the year so it should produce successfully in Otago.

Rainfall and Irrigation

Rainfall does affect ginseng. However, the leaves are very susceptible to fungal disease when wet. In North America, growers spray fungicides almost as soon as it has stopped raining.

If irrigation is needed a T-tape or drip system on the soil surface is thought to be the best.

Wind

Ginseng needs to grow in the shade and in most situations where this occurs, shelter from the wind is also provided.

Soil

The key physical requirement of the soil for ginseng growing is a free draining root zone with a high sand content. It makes sure the roots are not always wet which can lead to a range of different fungal and bacterial diseases and it allows the roots to be easily harvested without damaging them.

Fertility

Ginseng grows naturally on a forest floor which has a pH of around 5-6 and not a lot of excess fertility. It is a small, slow growing plant. Be very careful to not over fertilise as the plants can die.

Weed Control

You will be growing ginseng in relatively low light conditions. This tends to mean there are fewer weeds as they do not like growing in these conditions. If weeds do become an issue, hand hoeing or pulling is considered the best way to manage them.

Varieties

American ginseng (Panax quinquefolium) is the most commonly grown ginseng in commercial blocks. Seeds and technical growing information is freely available. Asian ginseng (Panax ginseng) is a little rarer but grows the same as the previous species.

Pests and Diseases

Ginseng plantations are badly affected by fungal diseases all over the world. A preventative spray program is recommended during the growing season. Insect pests are less common with the exception of grass grub and porina caterpillar which can eat though a bed of roots in a short space of time. Wire worm has also been observed in some New Zealand plantations. The worst pest species is actually birds that pick at seedlings removing them form the ground where they dry out and die.

Layout

Traditional planting densities are 200 seeds m2. After 4 years of growth and seedling death this usually ends up in a harvest of 70-80 plants m2.

Seeds should be stratified before sowing to break dormancy, especially if they have been imported from the USA. After sowing approximately 3-5cm deep a mulch of weed free straw should be added to the blocks. This will need adding too every season.

General Management

After planting it is a minimum of 4 seasons before harvest. The main aim during this time is to keep the plants healthy. This means watching for pests and diseases and removing any that show signs of infection along with spraying and weeding. The plants die back naturally in the winter and do not need to be cut back or looked after during this time.

Harvest

Roots are harvested using a modified potato digger, dragged through the beds. People with baskets behind the digger pick up the roots sitting on the soil surface. They are then washed and dried down to a moisture content of between 8-10%. Once this is done the crop is ready for sale. Dried ginseng roots will store for several years if the humidity levels are low.

Equipment

Many growers start with a rake, some seed and a cover structure or they grow under trees. Larger growers have very elaborate set-ups with tractors rotary hoes, beds formers; spray rigs, straw spreaders etc. Contact your local New Crops Centre to watch a video clip of the types of equipment needed.

Returns

Some New Zealand growers are quoting up to NZ $400/kg of dry roots. Quite where this number comes from is unknown. Current international price for this crop, based on the North American industry is about $50/kg.

Contacts

If you are thinking of growing Ginseng contact Crops and Food Research and buy the following book. It contains a lot of useful information and contacts. The easist way to do this is go straight to the link below

Ginseng: A Growers Guide: by B.M Smallfield, and J.M Follett

http://www.crop.cri.nz/home/index.jsp