Peter Hines claims he lost orchids worth pounds 93,980 when the gas supply at Wide-Gate Nursery, Elburton, near Plymouth, broke down in freezing weather in November 1989.
Mr Hines, of Torpoint, Cornwall, alleges Calor Gas, of Slough, Berskshire, which installed gas at the nursery the previous September, was to blame. The company denies liability. It says the supply must have been interfered with.
Mr Hines's counsel, Adrian Hughes, attributed the failure of the heating system to the lack of an automatic changeover valve between the two fuel tanks, or the incorrect setting of regulators on the tanks, or the incorrect specification or installation of pipework.
Mr Hines, 67, said he had been growing orchids since his schooldays and had received gold awards at the Chelsea Flower Show and internationally. In the past he had favoured oil heating, but had heard that Calor Gas was making a push into horticulture. Before he ordered his system, he talked to staff at the company's Plymouth showroom. 'I explained in detail what I wanted in relation to reliability and temperature lift.'
The cold snap in November 1989 which ruined 3,000 of his plants - many of them rare - was a 'freak occasion'.
He denied that he had switched off a valve on the system. 'That's not true. I never touched a valve on either tank at any time in my life. There would have been no reason for me to.'
Mr Hines said orchid growing was his 'first love'. He was 'devastated' by the loss of his plants and his dreams for the future were ruined, he said.
The hearing continues.