A picture book afternoon at the very end of summer. The Year 5 children who squat beside two rows of French beans have just made a discovery. Word travels fast along the lines. “Hey, you can eat them!” “Just pick them off and eat them?” “Yeah. They’re lovely!” So now they are torn - between stuffing the crunchy green sticks straight into their mouths, or cramming as many as possible into their plastic bags. It’s a dilemma that’s as old as the human race. But for this generation, perhaps more than for any previous one, harvesting is an absolute novelty. For too many children raised under the bright lights of a convenience culture, food has become a freezer-to-fryer affair - something plucked from a supermarket shelf to be unwrapped and microwaved, or served up fast and fatty in a polystyrene box.

Not for them the uncertainty of germination, the marvel of fertilisation, or the joy of ripening.

Small wonder, then, if their enthusiasm for eating vegetables and fruit is strictly limited. But for the children who now chomp at French beans as if they were chocolate-coated honeycomb, and who will soon be crushing cherry tomatoes between their back teeth like so many cream eggs, the future may be a little greener. With around 300 other pupils from schools near Selby in North Yorkshire, they have this past year been taking part in a pilot project aimed at reconnecting them with the growing process. The hope is that having a hand in the production of healthy food will make them feel more positive about eating it.

Fruit and vegetables are cocktails of more than 100 beneficial compounds including antioxidants, vitamins and minerals. Yet one in 10 young children eats no fruit at all, and three-fifths will not touch a leafy green vegetable, according to the most recent National Diet and Nutrition Survey.

Half do not even drink fruit juice. Only about one in 25 is consuming enough of these natural cocktails to protect themselves against many cancers, heart disease and strokes, not to mention asthma.

On three and a half acres of land at the Stockbridge Technology Transfer Centre, a horticultural research facility just north of Selby, a dozen primary schools have each been given a plot. And four times throughout the year - at Easter, at the end of May, in early July and now in the last days of summer - parties of children have visited their plots, to sow seeds, pull weeds and generally nurture their crops of potatoes, carrots, beans, onions, courgettes, lettuces and tomatoes in readiness for the harvest.

They are given outdoor lessons by three primary teachers who work there part-time, dealing with such topics as pollination, fertilisation and seed dispersal in a way that links closely with the national curriculum.

The Outdoor Classroom project at Stockbridge is jointly funded by the European Union, the Department for Environment, Food and Rural Affairs, and the private sector. It is just one of many schemes up and down the country that share a common aim: namely, finding new and effective ways of persuading children that fruit and vegetables are not only good for their health but can also be good to eat.

Children and their parents are key targets of the 5 A DAY campaign which was kick-started with pound;52 million of Lottery cash from the New Opportunities Fund. This scheme, which urges people to eat five portions of fruit or vegetables every day, pulls together a wide range of national and local projects. The largest of these is the Department of Health’s ambitious National School Fruit Scheme, which is on target to deliver free fruit daily to all four to six-year-olds in England this year.

What is behind the explosion in public spending on “healthy eating” initiatives? Graham Ward, chief executive at Stockbridge and the man behind the Outdoor Classroom project, puts it bluntly. “The Government thinks it’s worth spending pound;50m a year trying to persuade people to eat fruit and vegetables now rather than buy pills in the future to cope with obesity, diabetes and heart conditions,” he says. “In my mind, it’s probably the biggest social interference since the last war, and it’s about trying to avoid the National Health Service going bust in 30 or 40 years’ time.”

Many of the children at Stockbridge, particularly those from urban schools, come from homes where food is rarely cooked. They have had next to no contact with fruit and vegetables in their natural state.

“More than half of one class had never seen beans before,” says Pat Kay, one of the teachers at the centre. “I asked if they had any idea where potatoes came from and only one hand went up. They were quite ecstatic when they got the forks and these things started coming out of the ground.”

Her words are echoed by Richard Siddall of Sustain, an alliance of organisations campaigning for “better food and farming”. In 2001, Sustain launched Grab 5! to promote fruit and vegetable consumption among children aged seven to 11 from low-income families in Lambeth, Leeds and Plymouth.

“When we organised tastings in schools,” he says, “it was surprising the number of children who had never tasted melon or kiwi fruit, or even different varieties of apples.”

Children harvesting vegetables at Stockbridge this summer have been encouraged to take bags of produce home with them. Vegetables from their plots have been sent to schools and served for lunch. Parents have also been involved and families encouraged to grow tomatoes in hanging baskets at home. (“If kids grow something, they’re going to love it no matter how awful it might be,” says Richard Siddall.) The Stockbridge project is set to double in size next year, taking children from twice as many schools and drawing in other farmers and growers. There are plans to invite chefs to the centre, to show the children that there can be more to cooking vegetables than boiling them, and to design a tool kit that will enable other schools to run similar programmes in their own backyards.

And alongside all this activity, there is the serious business of assessing the impact the project has on participants’ eating habits. Already a research team from the University of York has made a start, doing what Graham Ward calls “some proper science on social behaviour and skills”.

“They will be looking at what the lasting effect is on the kids and on their parents,” says Mr Ward. “That will take the whole thing from being ‘nice’ to actually achieving something.”

Rosie Denison, co-ordinator for the national 5 A DAY programme in the Yorkshire and Humber region, believes that the Stockbridge strategy will work because it involves the active participation of the children. “They are the ones who are planting and growing. That way, they don’t feel like they’ve been told.”

A large component of 5 A DAY, says Ms Denison, is working with parents and training health professionals about how to work in communities. But it’s clear that anyone expecting instant results will be disappointed. “There are a lot of problems and everybody knows it’s a huge task because we’ve missed a few generations. But these children are the future parents, and even if we can’t do much about the immediate problem, we can at least do something about breaking the cycle of deprivation.

“They might not start eating fruit and vegetables there and then,” she says, “but the evidence shows that it can happen later in life, when they are disentangling their hormones and readjusting to adulthood.” As any nine-year-old who has visited Stockbridge knows, the first job is to sow the seeds. As for harvesting, that comes later.