The Prince of Wales was right all along. Plants really do like it if you talk to them.

What he did not know is that they prefer to hear a woman’s voice. And what really encourages them to grow is a direct descendant of Charles Darwin.

These are the conclusions of a month-long study by the Royal Horticultural Society (RHS) into the effect of the human voice on tomato plants.

More than two decades after the Prince exposed himself to ridicule for saying it was “very important” to talk to plants and that “they respond”, horticulturalists at Wisley believe his hunch was correct.

After a classified advertisement was placed in The Times inviting members of the public to audition for roles as plant whisperers, ten different voices were chosen.

Recordings were made of the volunteers reading passages from Shakespeare’s A Midsummer Night’s Dream, John Wyndham’s The Day of the Triffids and Darwin’s On the Origin of Species.

Each plant “listened” to a different recording through the headphones of an MP3 player attached to its pot at root level.

The plants were kept in the same greenhouse and measured before, during and after the experiment. Control plants were not exposed to the sound of a human voice.

The plant that grew the most had been listening to Sarah Darwin, great-great-granddaughter of Charles, reading his revolutionary work. Her plant grew 1.6cm (almost two thirds of an inch) higher than the most successful of the two control plants.

Ms Darwin: “I think it is an honour to have a voice that can make tomatoes grow, and especially fitting because for a number of years I have been studying wild tomatoes from the Galápagos Islands at the Natural History Museum in London.

“I’m not sure if it’s my dulcet tones or the text that I read from On the Origin of Species that made the plant sit up and listen, but either way I think it is great fun and I’m proud of my new title [as The Voice of Wisley].”

Colin Crosbie, garden superintendent and curator for The Voice of Wisley experiment, said that there was “something wonderfully pleasing about a plant responding to a story about how its kind came into being”. He said: “We can’t explain exactly what the magical property in Sarah’s voice is but it could have something to do with the pitch and tone of her voice.

“Our experiment also found that female voices had the edge over male voices in helping plants grow.”

Mr Crosbie has long been convinced that plants respond to human vocal encouragement. “I’m a great believer. I definitely talk to plants. Most gardeners are quite tactile and we do talk to them. Sometimes we talk kindly, sometimes we threaten them.”

On the whole the five women volunteers outperformed the men.

Indeed, I am sorry to report that my own efforts, as representative of The Times, were dismal. The poor plant that had to endure my rendering of A Midsummer Night’s Dream and The Day of the Triffids on a continuous loop for a month grew less than both control plants.

Previous research has looked at the relationship between plants and music.

In 2007 Mi Jeong Jeong, a South Korean scientist, discovered that playing Beethoven’s Moonlight sonata to rice plants led to faster growth and earlier blossom.

Now that the RHS is convinced that plants do respond to voices, researchers just need to figure out why they prefer women over men.

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