Gardening guru Alan Titchmarsh has said children must get out of the classroom and spend more time outdoors.
The former Chelsea Flower Show and Gardeners' World presenter said more time should be set aside in the school curriculum.
Titchmarsh, 70, who is back on TV fronting a new series of behind-the-scenes documentary Secrets Of The National Trust, said gardening is "therapy".
He told PA: "The curriculum should cater for, at least, several periods each week, outdoors.
"Even in inner city schools you can do it. There are green spaces. We know it's good for them, they let off steam.
"I don't need to spout Latin names at my grandchildren but they adore being outside, whether it's collecting eggs from chickens or picking raspberries or just running around.
"They are the future custodians of the landscape. We need to get them familiar with it."
The novelist and former chat show host said it was not enough to grow up knowing about global warming.
"We can't keep bringing them up just telling them disaster stories and what's going wrong," he said.
"They will all grow up knowing about global warming and climate change."
He added: "It makes me smile when I see something that says GPs are saying that gardening is good for you.
"Oh really? Tell me something else I don't know! ... Gardening is therapy."
Secrets Of The National Trust With Alan Titchmarsh starts tonight (Tuesday 23 July) at 9.15pm on Channel Five.
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