In early winter, shade is removed and if harvesting is to be carried out the mulch is removed. Harvesting is carried out using modified potato diggers after the tops have started to die but before the ground has frozen. Because of the risk of disease, which is considered to be one of the main limiting factors to production, most growers in North America harvest their crop after three years. Soil fumigation, fungicides, good crop hygiene and good drainage are all considered essential in the control of disease. Although diseases can cause widespread destruction of the crop with the exception of root knot nematode there are few pest problems.
Theft is a major problem in North American crops.
The cultural requirements of Korean ginseng are similar to American ginseng but are usually smaller in scale and more labour intensive. Processing and quality After harvesting, the roots are tumble-washed in water. Roots are then either placed in a drier or cool stored for up to eight weeks prior to drying. In North America, drying is often carried out in modified tobacco kilns. Once dried, growers usually sell their crop as a single grade to a buyer or broker.