However, three years ago a study by Exeter University left Riverford, the Peterborough based veg box suppliers, with a difficult ethical problem: squaring customer demand with environmental costs and English weather. The study showed the cost of maintaining a 20C temperature to produce tomatoes, cucumbers and peppers in a single glazed British greenhouse in January was in environmental terms "insane."
Instead the organisation decided to buy in these crops in winter from two growers in Andalucia in Spain. The transport costs by lorry to England are far less damaging to the environment than the heating, and with more natural growing conditions and a change in varieties the crops taste much better. The greater problem has been finding British growers prepared to provide the same crops for the summer without heated greenhouses. With just a 12-week harvesting season, suppliers said they could not make the system economically viable.
As a result Riverford staff decided to do it themselves and build three acres of sophisticated plastic skinned greenhouses. These will grow tomatoes and cucumbers in the summer and salad leaves in the winter. The company believes this will be the best way to grow low impact salads.