I found this
"The first step is site selection. Favorable soil and moisture conditions are most often associated with north or east facing slopes with at least 75 percent shade canopy. This is dense shade we're talking about. The best shade is provided deep rooted, deciduous trees such as Poplar and Oaks. Ginseng grows best in a moist well drained soil. That is a contradiction, but these soils do exist. Successful growth of ginseng most often occurs in sites where herbaceous woodland plants such as Jack-in-the-Pulpit, Bloodroot, Solomon's Seal and ferns are thriving. If no herbaceous plants are growing
on the forest floor, ginseng will probably not grow there. Excellent soil drainage is essential and swampy or clay soil must be avoided.
conditions for ginseng are more difficult to find in low-lying regions than they are in the mountains. The forest floor in most woodland areas is too hot and dry during the summer for ginseng to thrive. (Moist environments may be found that are good, if not perfect, places to grow ginseng.) Small pockets of cooler soil may be found very often on a north facing hillside above a stream or river"