You can keep potatoes in the ground for some time unless it is extra wet conditions. Then some may sprout or something.
The skins would toughen some in the ground but perhaps not fully. You might want to add some dirt on top to make sure they all stay covered well.
I feel that the ground is a better storage place than most storage that the average person has. Course when freezing comes they need a better place than where they grew.

There are advantages and disadvantages to both ways of storage, in-ground or dug.

In-ground will stay moister and fresher. But, they may rot if too wet, and can be attacked by insects like wire worms and by voles. They also may start to grow in a few weeks to a few months, depending upon climate, variety, etc.

If dug, you can control the storage conditions and keep them away from insects and vermin, but they may dry out or rot if not properly stored, and of course, it does start the clock ticking in terms of drying out and sprouting.

So, I guess you have to weigh the pros and cons. In my personal situation, I have a lot of problems with voles in my garden, so I dig root crops as soon as they are ready to harvest -- nothing is more disappointing than digging a nice big potato, sweet potato, carrot, beet, etc., only to find a big hole gnawed out of one end of it.

Dennis
SE Michigan

Thanks folks!!

Or you can dig some now and leave some in the ground to mature.

I grew up among subsistence farmers and they never put all their eggs in one basket, literally or metaphorically.

I remember my mother mentioning that grandpa dug his potatoes, then mounded over them with dirt. This would make sense as he did not have a basement or cellar. He was doing this in the 1920's to 1940's in the Piedmont region of NC (zone 7B).
However, I don't know exactly how he constructed the mound or if he used dried grasses, weeds, or hay to layer them. I wonder how he kept them dry or at the right temperature through a winter in NC.
Does anyone on this forum know how to do this?
zinia