Gareth,
This is where making good decisions will pay off for you. Your soil samples will tell you every thing you need to know. If you get back readings that show a need to add lots of any thing, don't buy it. What you are looking for is soil that has lots of high grade limestone in it. This almost assures you of getting all the other ingredients that ginseng needs. The soils along the Blue Ridge Escarpment are these types of soils. They extend on into the Max Patch, Walnut Mountain, Bluff Mountain and some surrounding areas of the Appalachian Chain. About all that you need to do in this general area is put your seed in the ground. Many of the other areas of the Appalachian Mountains will grow ginseng well, but the roots will be a little smaller due to needing Phosphorus and Calcium. As far as micronutrients go, Magnesium would be the only other one that might need to be adjusted and that would be from lots of rain leeching away available Mag. If you get a piece of ground that needs a lot of fertilizers, you are defeating your purpose and will never get the best results that you would get otherwise. It's possible to find a piece of ground that comes close to having the Calcium requirements you need and adding Gypsum can help. My woodlots needed extra Calcium so I've added some each year for 3 years. That's not too hard in a woodlot, but sizeable acreage is different and can be costly. If you apply heavily, 2 times in the lifetime of ginseng is probably enough.
I've given you the general ideas, now is the time to get with the locals and find the piece of ground that will work. Your County Agent can help greatly and maybe other growers in the area that you choose.
Hugh
