I can only speculate here. Captain would need to confirm whether this assumption is correct:
I assume that the “The 3 Ginsengs” field simulates the actual effects in the body that would happen when one consumes the ginsengs.
In the field description it speaks of re-creation of the “effects”, not re-creation of the actual ginseng plants. So whatever effects the consuming of these ginsengs would usually trigger in your body, this field triggers these effects.
Field description:
PS:
It should also be obvious that ANY type of physical healing will also require for physical building blocks in order to create more new cells etc.
For example, with the Advanced Healing field, there was said in the thread discussion that if one heals 7x faster, then one also needs to provide the body with 7x the amount of nutrients and much more sleep.
Most people here do not get out the most of the physical healing fields because their diets are bad and insufficient!
Also quoting Captain here: