Wiltshire farmer Dr Steve Rothwell claims to have harvested the country's earliest ever crop of pea shoots.
The shoots form part of the Vitacress-owned Steve's Leaves range, which are washed in spring water and bagged in Hampshire.
Rothwell said he was in no hurry to harvest because the leaves are only taken when they have attained their distinctive fresh-pea flavour.
"We grow them slowly and naturally to ensure great quality. But the recent warm weather means that we can supply our customers with British pea shoots right through to the autumn."
Steve's Leaves Pea Shoots and Baby Leaves bags are available from Tesco, Sainsbury's, Waitrose, Ocado and Wholefoods with an RRP of £1.35 for a 60g bag.
Meanwhile, British asparagus, grown under polythene, has also hit supermarket shelves well ahead of the season's traditional 23 April start date.
Asparagus Growers' Association chairman and Norfolk grower Andy Allen told Grower: "We have begun to cut spears. The crop as a whole is slightly earlier than usual, although the cold nights have stopped it getting too far ahead."
He declined to predict likely volumes this season. "It completely depends on the weather," he said.
Dr Steve Rothwell is also a food scientist who maintains that pea shoots are the healthiest of all salad leaves because of their high content of vitamins A, B and C.
Steve's Leaves growers also claim to be the only fresh produce farms to have been awarded Nature Friendly Farming status by Conservation Grade.