The Sustainability Consortium has produced a number of "category sustainability profiles" for individual lines including tomatoes, identifying measurable goals to improve sustainability in the production of each. "It gives rigour to the things they ask for," said Lambie.
The method employs a life-cycle analysis of all inputs and outputs to yield an overall score per tonne of production. When this analysis was conducted at a tomato grower in the Netherlands, more than 90 per cent of the score was found to be accounted for by energy use.
"By comparison, growing-medium and crop-protection products are insignificant," said Lambie. But fertiliser and water use would have an impact, he added.
The grower concerned managed to lower his score per tonne by 40 per cent over 10 years through measures such as energy screens, Lambie explained.