I think the short answer is yes, you can water ginseng. However, the danger is too much water will (notice I did not say might, or maybe or could..but WILL) cause root disease in ginseng.
I would be careful doing so, but in times like these don't think a little watering would hurt.
To give you a rule of thumb, I grow my SELECT rootlets in a peat mixture in a raised bed. This means they hold some water, but dry out before the ground does. I have only watered them about three or four times during this hot weather. I soak them well early enough in the day for the plant surfaces to completely dry. This avoids disease issues. Then, I won't water for another week or so, even if the hot dry stuff continues. Be sure to let the ground/soil dry out between waterings.
Be sure to let us know what you find out if you try it.