The broadcaster and gardening expert reveals on Radio 4’s Gardeners’ Question Time on Friday that a constant diet of Black Sabbath worked wonders on a greenhouse full of plants, but exposure to Sir Cliff Richard killed every plant in a horticultural experiment.

Black Sabbath, led by singer Ozzy Osbourne, are seen as pioneers of heavy metal with tracks such as Iron Man and Paranoid. Beardshaw says using rock music as a nutrient appears to create larger flowers and they are more disease-resistant.

The test came about because one of his horticultural students wanted to write a dissertation based on the effects of music on plants.

“We set up four glasshouses with different sorts of music in to see what happened to the plants.

“We had one that was silent – that was a control house – and we had one that was played classical music, we had one that was played Cliff Richard and we had one that was played Black Sabbath.

“It was alstroemerias we were growing and we bombarded these glasshouses with sound for the life of the plant.”

He tells listeners, in the show to be broadcast at 3pm: “We were measuring incidence of pest and disease, we were measuring inter-nodal distance, we were measuring the floriferous nature of them and that sort of thing and so the one that was grown as a control house grew really well as you’d expect.

“The one that was grown with classical music — a soft, almost a caressing of the plant when it is hit with that sort of soundwave — those grew slightly shorter because of the soundwaves bombarding them and were slightly more floriferous and there was slightly less pest and disease.

“And the ones with Black Sabbath — great big, thumping noise, rowdy music — they were the shortest, but they had the best flowers and the best resistance to pest and disease.

“The alstroemerias in the Cliff Richard house all died. Sabotage was suspected but we couldn’t prove it.”