If you can plant in a area where you are finding decent 4 prongs here and there then I would not bother with a soil test.
Just plant in the same general area that you found those 4 prongs and I would sure expect your plantings to do well.
Most States have a place you can go to get a soil test done. Here in TN - I collect about a cup of dirt (from the top 4\" of soil) and collect several samples from the hillside I intend to plant, then mix that up and take a 1 cup sample of that and send it off for the soil test. My test here cost 7.00 and we get a fairly detailed test results report back.
You would need to check with your state or county ag office and see what your options are.
The main thing for growing healthy ginseng is calcium content and also soil PH.
Calcium levels best in the 3000-5000 pounds per acre range but over 2000 is good enough.
PH best around 5.5.
Soil test will give you those details and more.
Again - if you are finding decent 4 prongs in a area - I would not bother with a soil test.
If you were finding seng in a area, but only smallish 3 prongs, then you might want to check the soil. Areas like that are likely going to be on the low side on calcium.
If your PH is in the 5.5 range, but calcium is low (below 2000) you can increase calcium content by adding gypsum.
Gypsum will increase calcium without affecting PH.
If your PH was low (say 4.0-4.5) then you could add some Lime or Bone Meal to add calcium and raise the PH. Lime and Bone Meal will both add calcium but will also raise PH.
My place that I planted last fall - soil test showed PH in the 5.4-5.7 range (ideal) but calcium levels in the 1450 range (low). I used gypsum to increase calcium without affecting PH.
The reason I did my soil test was that I have ginseng growing here on my place but hardly ever find a 4 prong - mostly small 3 prongs (even when 20+ years old). So I knew my place was not ideal for seng, it grew here but was not really thriving.
I also have fairly heavy timber on most (mature hardwoods) and fairly deep shade. Too much shade can make seng grow slower than ideal. Could take you much longer go grow decent sized roots if too much shade.
Sites that get some good morning sun, but then are shaded well the rest of the day - seem to work well.
Check your hillsides for areas that get good morning sun but are shaded well the rest of the day. That is where I would put some plantings in first.
1000-1200 seeds will make 1 bed 5'x50' long (250 sf).
When you first start off it will probably take you a couple hours to plant a bed like that. As you do more you will get faster. It takes me 45 minutes to 1 hour to plant a 250 sf bed but now I am 50 years old (will be in September anyway) and I don't get in any big hurry when panting.
I can plant a pound of seed by myself in 6-7 hours.
Others here have reported much faster results but when you first start out don't expect to be that fast at it. Take your time and do it right first, then you can improve on your speed later on.
Best of Luck.
PS - when you get a chance check out my youtube channel.
Several vids on hunting seng, and some on planting wild-simulated too.
Also check out our friend Billy's channel - some real good seng hunting video's there.