Choose autumn onions and shallots for growing through winter. Wait to sow your onion seeds outdoors until May or sow them earlier undercover where they can develop free of frost. The underrated pink and white Onion 'Isobel Rose' is bred in Lincolnshire, UK, so it is well used to performing in our cool climate. Just shy of being a red onion and too blush to be called a white variety, this attractive onion toes the line, managing to keep a mild flavour perfect for eating raw.