Ok, my two cents, First off if you leave the rootball intact then the plant is still a living, breathing plant, so all you are doing is stressing the hell out of it. If you leave the plant in the ground and it dries look at it from the standpoint of other crops, corn or soy beans, the plant has finished its life cycle, it is dead, IMHO not the thing to do for a harvest of this crop. Everything is past its peak THC wise, to me you just wasted your whole grow. The idea is to harvest when the trichomes are at your desired level, not when everything has degraded.
If you are wanting to dry it as slowly as possible without mold then harvest the entire plant and hang whole. The plant will only be able to use the moisture left in the plant itself. In almost 7 years in this forum I do had it you for coming up with a question I haven't seen before. Best of Luck to you.