Sticking a nail into an onion may sound odd, but it’s an old household trick with practical roots. Traditionally, a rusty iron nail was inserted to release small amounts of iron, helping boost iron intake when the onion was used in soups or broths. It was a simple, natural way our grandparents addressed iron deficiency using everyday items.
The trick also appears in gardening and folk remedies. Iron-enriched onions were believed to support plant growth when planted, improve soil health, and even enhance the onion’s antibacterial properties. In cooking, the method was sometimes used in pickling to deepen color and improve texture. What seems strange today was once a clever, multi-purpose solution passed down through generations.