Sea kale is a brassica grown commercially by one Scottish grower, Sandy Pattullo at Eassie Farm in Angus, better known for his asparagus crop. Like forced rhubarb, the sea kale plants are grown in a dark, heated room in late winter, from January to March, so that early, tender shoots are forced upwards searching for light. These pale shoots are then harvested and sent to chefs around the UK who seek out its unique nutty flavour.

Sea kale used to be quite common, traditionally grown by fishermen's wives, who buried the plant as it grew so shoots were forced to come up to the light. In the 19th century it was grown in the same way in walled garden pits.

It then went out of fashion as more exotic vegetables became widely available during the winter months. But as the tide turns back towards seasonal, home-grown vegetables, Sandy Pattullo says its popularity is returning. 'People are becoming more selective in their tastes and they appreciate a special, local flavour,' he says. He began growing sea kale in the 1980s, and he expects demand to continue to grow.