The promotion, which was introduced in 2003 with three stores taking part, sees potatoes grown within each store's local area lifted - by hand - and delivered on the same day. The potatoes are supplied through Greenvale.
Greenvale said it had developed a growing process to meet the campaign's timings, which included a specific fertiliser and irrigation regime. In some cases, the food had travelled fewer than 10 miles (16km) and the time taken from lifting to being on the shop shelf was as little as 15 minutes.
Greenvale key account manager Charlotte Manwaring said sales increased on average by 80 per cent during the promotion. "We have the infrastructure in place to be able to implement this kind of scheme," she said.