I had always heard the same advice repeated everywhere: never store potatoes next to onions. The claim sounded confident and scientific enough that I never questioned it. Potatoes go bad. Onions are nearby. Case closed.
Then I noticed something odd. My potatoes spoiled even when the onions were nowhere near them. Other times, they lasted just fine sitting close together. That inconsistency pushed me to look past the rule and figure out what was actually happening.
What Potatoes Really Need to Last
Potatoes do not need tricks. They need conditions.
They last longest in a cool, dry place away from light. Heat speeds up spoilage. Moisture invites rot. Light triggers sprouting. Crowded storage traps humidity and stale air.
When I moved my potatoes into a paper bag, kept them away from sunlight, and gave them airflow, they stopped going bad as fast. No onion-related changes required.
Why Onions Got the Blame
The onion warning comes from confusion around ethylene gas. Ethylene is a natural gas produced by fruits and vegetables as they age. Some produce releases a lot of it. Some is very sensitive to it.
Potatoes are sensitive to ethylene, but onions do not produce much of it. That means onions are not accelerating potato spoilage in any meaningful way.
What does happen is simpler. In a closed, poorly ventilated space, potatoes can absorb odors from onions. The potato does not rot faster. It just smells off.
That smell gets mistaken for spoilage.
What Actually Makes Potatoes Go Bad
The real problems show up when potatoes are stored in warm kitchens, near appliances, or sealed in plastic. Heat raises respiration. Plastic traps moisture. Both shorten shelf life.
Light exposure causes sprouting. Tight storage limits air movement. None of these issues involve onions.
Once I focused on environment instead of pairing rules, the pattern became obvious.
How I Store Them Now
I keep potatoes in a paper bag in a dark cabinet or pantry, away from heat sources. I do not seal the bag. I leave room for air to move.
Onions stay nearby but not pressed together. Not because they cause spoilage, but because I do not want shared smells.
The difference in how long potatoes last has been consistent.
The Takeaway
Potatoes do not go bad because onions are nearby. They go bad because of heat, moisture, light, and poor airflow.
Separating onions helps with smell, not spoilage. The internet simplified the advice. The science tells a quieter story.
Once I stopped blaming onions and fixed the storage, the problem stopped repeating.
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