As a result of global food sourcing and advances in packaging and preserving technologies, the Western world has grown used to the availability of a wide range of food produce throughout the year. In particular, advances in 'modified-atmosphere packaging' have increased the shelf life of prepared salad product by over 50% enabling supermarkets to sell washed and bagged salad from around the world.

In late October, when the UK salad season comes to an end, much of the production moves over to Spain. Several English producers have bought farms in the Andalucia and Murcia regions in order to keep...