[QUESTION] How long can you store potatoes before they begin to mold?

I don't think I've ever had a potato become moldy. On the rare occasion that they go bad, they just get kind of shrivelly.

I don't think I've ever had them mold/rot on me (unless they were in plastic packaging). They usually start growing before that, and I'll sometimes plant them lol.

I’d get them in plastic, and try to cut the top side of the bag all open within a few days, and often I get through them all without problems but sometimes not.

I do now have a plastic container I could dump them in that could be an improvement. I’ve thought of cardboard boxes but I imagine spores getting into the cardboard for the next potatoes and maybe moisture from the potatoes being a problem.

My mother kept potatoes in a plastic container in a cabinet, but I don’t know how well they kept or how quickly we used them up.
- We grew all kinds of vegetables growing up, and potatoes were one of them. We kept them in a big wooden bin in the cellar and they very rarely, if ever, rotted between seasons. Would use what was left over in the spring for planting (a lot of them were already growing by that point lol).
  
  Moisture is an issue. Dogs knocked their water dish over, and some of it went under the door into the pantry where a bag of potatoes was sitting. I didn't notice it for several days, and those did rot. Rotting releases more moisture which spoils any adjacent, and so forth.
  
  So I guess as long as they stay cool and dry, they're golden. Though once they start sprouting they're less ideal to use for cooking (and difficult to peel, too).
I actually just had my first bag of potatoes go bad on me, while others have lasted months. What is the deal with plastic packaging in this situation?
- I have no idea, TBH. I've always bought them in bags where they could "breathe", and those all eventually start growing (rather than rotting/going bad) if I forget about them in the pantry for too long. The only ones I've ever bought that were plastic-wrapped were big, baking potatoes. Maybe it keeps them from sprouting for a bit longer?
Some may have some spots that look like rot but they're very localized. Never had mold I don't think. Some cut ones had some white on them but that didn't seem to become fuzzy. I don't think I've ever seen potatoes sold in plastic though - unless you mean plastic nets, but I assume you mean like actual plastic bags or something. I empty mine on like a double layered cover of an old fan, so it sits in a big pan of grating basically. No active ventilation though.

Practically impossible to say. You never know how old potatoes you get from the store might be. Maybe a few days, maybe a few weeks. I've had freshly harvested and cleaned potatoes go months before showing new root growth on the outside, but I've had a new bag of potatoes have one or two turn moldy in a few days.

As a child my family would store potatoes in our cellar all winter into the next year where we would plant them again. Staying between 45-50°F, with high humidity, good ventilation, and no light will make them last 6 months or more.

wait. you want high humidity?
How did they store them? The only cellar I’ve ever been in was of the house we lived in when I was a little kid, and I remember it as so wet and filled with spiders, and maybe the average cellar isn’t quite like that.
We put our save potatoes in a burlap sack and buried them below the frost line. They came out in the spring almost exactly like they went in in the fall.

Depends on conditions.

Traditionally potatoes were harvested in fall (just before the first freeze) and stored in a root cellar with stable, cool temps (above about 45) and moderate humidity (IIRC, between 40-60%), and well stacked (good airflow between them, like with straw or even in bushel baskets. I've read storing them in sand is a great way to stabilize moisture loss.

Stored like this they last all winter. They tend to dry out some, get soft and wrinkly, but completely fine to eat.

My root cellar is low humidity and a little warmer, so at 3 months they're a little dry and wrinkly. I've never, ever had mold on potatoes. Mold is a result of high humidity and no air flow.

They do require attention while stored - like other fruits and veg, if one goes bad it'll affect the others.

Interesting. I’d read how vegetables “used to” go in root cellars for winter, but I would just imagine a hole dug in the cellar of the house where I lived as a kid, and vegetables dumped in. I had no idea of stacking or anything.

I live in a desert so extremely low humidity and the pantry area is often over 80. I've used potatoes over a month after buying them many times. I still use them for myself if they have small sprouts. I usually don't see mold until closer to two months in. If I'm cooking for others I'll buy fresh. Our local grocer has a very small selection of produce so I tend to buy a bunch of the nicer ones if I see they've restocked since the next grocery store is about an hour away. When I lived in the city though I'd only buy what I planned on using within the next couple days. More trips but always fresh.