The former host of Gardeners Question Time has accused Facebook of using the Chelsea Flower show to improve its “tarnished reputation”.

Next month the 'Beyond The Screen' garden by award-winning designer Joe Perkins and sponsored by Facebook will be shown at the horticultural event.

Facebook says its £75,000 coastal-themed landscape garden will highlight how social media is a "powerful force for positive change in the real world".

However Professor Stefan Buczacki, former chairman of Gardener's Question Time, said: "It is a backhanded compliment to the influence of gardening that Facebook wants to improve that tarnished reputation by associating with what is the most healthy, wholesome outdoor activity,” he said.

"The idea that Facebook will get young people away from their screens and into gardening is pretty bizarre. BBC producers had the same mantra for years that we must get young people gardening.

"But the reality is that young people will not be interested in gardening until they have their own garden and that is further away than ever these days because they cannot afford their own homes."

Matthew Appleby, of magazine Horticulture Week, added that it was “ironic” Facebook had a garden because “too much screen time is the biggest barrier to getting kids outdoors and into healthy activities like gardening”.

Mr Perkins, 42, of Hove, East Sussex, added: "Social media is not going away. We all use it. I have a lot of gardening books at home but I have not looked at them for over five years. If I want some inspiration or to find something out I go online."