The two have used Biotechnology and Biological Sciences Research Council (BBSRC) funding to work out the genetics of processable salad leaves, which has fed into a US breeder's salad crop breeding.
They found that smaller, tougher leaves with tightly packed cells lasted longer, then worked out which regions of the lettuce genome were responsible for this.
But the researchers also made the unexpected discovery that using less water when growing salad also improves its shelf-life.
Lead researcher Professor Gail Taylor said: "If you reduce water use in intensive salad production by about 20 percent, you actually develop smaller, tougher leaves with stiff cells walls, which is what we're interested in, and at the same time, the company can reduce their water footprint."
Vitacress has since adapted its growing in light of this finding.
Its production & technical director Dr Steve Rothwell said: "The results open the door to exciting further studies across a wider range of crops and geographies aimed at driving down the use of water whilst improving crop quality and shelf life."