To store onions properly and keep them fresh for as long as possible, follow these expert guidelines:
- Keep onions in a cool, dry, well-ventilated place. Ideal temperatures are around 45 to 55°F (7 to 13°C), or even cooler (35 to 40°F) for long-term storage, such as in a basement, cellar, garage, or pantry
- Ensure good airflow around onions. Store them in mesh bags, netting, wire baskets, wooden crates, or even old nylon stockings with knots tied between onions. This prevents moisture buildup and spoilage
- Avoid direct sunlight and heat sources. Light can cause onions to sprout and heat can accelerate spoilage
- Do not store onions in plastic bags or sealed containers at room temperature. Lack of ventilation causes mold and rotting
- Keep onions separate from potatoes and other produce that emit ethylene gas, as this can cause onions to sprout and decay faster
- For cut onions, refrigeration is recommended. Wrap them tightly in plastic wrap, aluminum foil, or store in an airtight container before refrigerating. Use cut onions within a few days to avoid odor spreading and spoilage
- Sweet onions can be stored similarly but may have a shorter shelf life. Hanging them in pantyhose or stocking legs in a cool, dry place with airflow is a traditional and effective method
- Regularly check stored onions and remove any that are soft or starting to rot to prevent spoilage of others
In summary, the key to storing onions well is cool temperatures, dryness, good ventilation, and separation from ethylene-producing produce. Refrigerate only after cutting. This approach will keep onions fresh for weeks to months depending on the variety
