Television gardening celebrity David Domoney says that as children spend more time on the internet and watching television they are becoming increasingly alienated from nature and gardening.
Mr Domoney, who co-presents with Alan Titchmarsh Britain's most-watched gardening television show, Love Your Garden, says he is alarmed at the decline of traditional outdoor activities once enjoyed by children. "We are fighting an uphill battle with the internet, and gardening is the loser," he states.
"Where has the simplicity of a garden tree house for children gone? Where they can climb a tree and connect with nature? A simple tree for kids to climb. A connection with the outdoors.
"When schools started banning leap frog and conkers on health and safety grounds in 2012 I became highly concerned.
"We need a fundamental shift in how children connect with the outdoors and not take the easy option of linking them up to smartphones, iPads and videogames consoles to educate and entertain them."
He goes on: "Young people spend too much time in front of a screen. It's highly addictive and unfortunately the virtual world seems more real than the real world for a lot of youngsters. We need to do everything in our power to get youngsters to reconnect with nature".
According to communication regulator Ofgem, teenagers today spend over 32 hours each week either watching television or on the internet, an increase of two hours per week in terms of online usage year on year.
And the Royal Horticultural Society says gardening is facing a skills crisis because of an ageing workforce and a lack of young people coming through.
Mr Domoney founded Cultivation Street and the Young Gardeners competition in association with Prince Charles, and is campaigning to encourage parents to engage their children in the pleasures of the garden.
At this week's Hampton Court Palace Flower Show he is also showing his Quiet Mark Tree House and Garden by John Lewis.