I can tell you from living in the Ozarks, and putting a lot of prescribed fire on the ground that a dormant season fire is the way to go.
However, if you have a situation where you have to put fire on the ground during the growing season start the fire at the top of the hill and burn down the slope. I recommend starting in the west and letting the fire burn down the hill toward the east. This mimics wild fire conditions in our area. Because ginseng is under the ground a backing fire should only kill the top, which will come back next year.
The fire will cause seeds laying dormant in the soil to sprout, with adequate sunlight, and provide lots of alternative foods for wildlife other than your precious ginseng plants.