The problem with younger roots is they have lesser amounts of Ginsenosides and Gintonins. Every country is different, but in the USA it is illegal to sell wild plants less than 5 years old for export. Cultivate crops can be sold at any level, but most people want them as old as possible because they are stronger. Selling a pound or two to a local herb store might not be any problem for a single pound or two. But if you are growing to sell in bulk to companies processing them into tinctures or pill form, they won't pay much, if anything for younger roots. When they are processed into a standardize potency, it would take more younger roots to produce the same amount of standardize pills, than an older root.