Onions

Whole onions keep 1–2 months in a cool, dark, well-ventilated place — not in the refrigerator and not in a sealed bag.

Ventilation is the priority. A mesh bag, a wire basket, or an open bowl in a cupboard all work; plastic traps the moisture onions naturally give off and turns them soft and moldy. The original mesh sack is well designed for this.

Keep them away from potatoes. The two accelerate each other's decline — onions release moisture and gases that make potatoes sprout, and potato humidity softens onions.

Once you cut an onion, it goes in the fridge in a sealed container and keeps about 7–10 days. Cut onions absorb refrigerator odors and give off their own aggressively, so the container matters.

Sweet onions such as Vidalia have higher water and sugar content and keep only a few weeks, not months. Refrigerate them if you want the longest life.

An onion is a bulb — a dormant storage organ built by the plant to survive months underground. Its dry papery outer skins are a natural moisture barrier, and its high sulfur compounds are genuinely antimicrobial. That is why onions keep for months while most vegetables keep for days.

Its enemies are therefore moisture and warmth, which signal the bulb that it is time to grow. Damp storage causes soft rot; warmth triggers sprouting, as the bulb sends up a green shoot using its own stored sugars. A sprouted onion is safe to eat — cut out the shoot — but it will taste increasingly bitter as the bulb is cannibalized.

The tear-inducing compound is syn-propanethial-S-oxide, released when cutting ruptures cells and allows enzymes to meet sulfur compounds. Chilling the onion first slows that reaction, which is the one genuinely effective anti-tears trick.

Cut onions should be refrigerated, not left out. The persistent claim that a cut onion "absorbs bacteria" and becomes poisonous is a myth with no evidence behind it — but a cut onion is a moist, exposed vegetable like any other and belongs in the fridge.

Discard onions that are soft and squishy throughout, leaking, black with mold at the neck, or smelling sharply rotten rather than pungent.