Tesco is stocking British-grown watermelons for the first time following a successful crop nurtured by a student.
Joe De Pascalis, 19, convinced his boss at S&A Produce, based in Marden, Hereford, that he could grow the crop.
Tesco, which has put them on sale, said it did not think people would be able to tell the difference between them and imported ones from Spain and Brazil.
Mr De Pascalis said he had “personally tended” to them three times a day.
The agriculture student from Leominster, Herefordshire, said the watermelons only needed artificial heating at the germination stage from a biomass woodchip burner.
Once planted, they received no additional heating, but were aided by the hot and humid summer.
Mr De Pascalis grew more than 150 watermelons for the supermarket chain as a first year trial.
He said: “I’m studying production horticulture and, as part of my apprenticeship, I have to demonstrate that I can grow produce from start to finish – overseeing every part of the process.
“The watermelons have been like babies to me throughout the 90-day growing programme and I’ve personally tended to them three times a day to make sure they were getting just the right amount of feed.”
Tesco produce manager James Cackett said the sweetness level was “very good”.
He said: “They are standard size, weighing between about one and three kilos each. We have chosen the varieties that are popular with shoppers.
“This is just a trial to see what shoppers think of them but, if the reaction is good, we will work with the growers to get more for next year.
“Joe has clearly done a very good job growing them and in doing so made a mark on British agriculture.”
The watermelons have gone on sale in Hereford and in Royston, Hertfordshire, priced at ?2 each.