But after a process of trial and error, and with the help of grafting specialists, Thompson & Morgan hit upon a method using a variety of potato that produces the right size shoot.
Careful variations in the temperature at which the tomato and potato are initially grown are also made to ensure the two plants are a perfect match before being joined together.
‘At the start, we thought it’d just be a novelty thing to do. But as the trials developed we realised what we had produced was really high yield, had fantastic flavour and could be done commercially for the first time,’ said Mr Paul Hansord horticultural director of mail order gardening company Thompson & Morgan.
It can be planted from late April and produces trusses full of tomatoes which have a traditional tangy, sweet flavour from July to October and a good hearty crop of potatoes of a versatile variety, which can be boiled, mashed, roasted or made into chips, for late in the season.
Mr Hansord added: Each TomTato plant is specially grafted by hand to create this unique double cropping feature. There’s no genetic modification – it’s an all-natural, and safe process.
Production begins in a specialist laboratory in Holland, where the delicate grafting process takes place. The plants are then shipped back to the UK and grown on in greenhouses until they are big enough to be sold.