Sow Ailsa Craig sweet onion seeds for huge, straw-yellow globes up to 20cm (8") in diameter! Firm, with mild, sweet flesh, Ailsa has fairly good short-term storage potential, certainly better than Walla Walla. Ailsa Craig Spanish onions are fine textured, and excellent for salads and sandwiches. It is tolerant of cold weather, so it can be ready for harvest before some other Spanish storage onions. Ailsa Craig was not a person, but rather a place. It is a stony island in the Firth of Clyde in Scotland. While the onion is not from there, it would certainly grow there, as it is adapted for growing between the 38th and 60th parallels, and that makes it an even better onion for northern growers.