The treatment could lend young plants in-built protection against key pests such as red spider mite.
Its potential was first discovered by British researchers at Lancaster University in work funded by HDC and the Natural Environment Research Council.
Nigel Paul, of the university's Department of Biological Sciences, said the chemical, jasmonic acid (JA), somehow switches on plants' natural defence mechanisms. Previous work had tried spraying JA onto plants, which also had the effect of controlling growth.
"We wanted to see if we would get the same benefit by treating the seed," Paul said.
Tomato plants raised from seed soaked in JA were protected from attack by red spider mite for at least eight to 10 weeks.
"It could be longer," said Paul. "That's what crop-scale trials will find out."
The trials are being conducted by Plant Bioscience, which holds the licence for the technology.
In a new project funded by Defra, Lancaster University researchers want to understand the biological mechanism behind JA, as well as seeing if it could have a role in preventing disease.