Jan Turner is used to welcoming guests. “Would you like a drink?” she asks, and returns with a cup of orange juice. Like almost everything else on the menu at Mapledene early years centre in the London borough of Hackney, it’s organic and, as the kids here all agree, yummy.

Eighty children come to Mapledene every day, and with parents and carers welcome to drop in at any time, there’s a constant flow of visitors to this bright and colourful nursery. Now it’s also attracting interest for its pioneering approach to a subject that is on the fringes of the curriculum but a central part of the school day - food.

Mapledene claims to be the first state-run nursery in Britain to go organic. As such, it has become a showpiece for the natural food movement, hosting press conferences for organic food watchdog the Soil Association, and visits from educational and nutritional experts, all keen to see how something so desirable in theory works in practice.

“When we opened, three-and-a-half years ago, it was part of our vision to look at the health and well-being of all the people who use the centre,” Jan Turner, head of centre, explains. Organic food was top of the shopping list, but finding a supplier was not easy; companies that deliver organic fruit and veg couldn’t cope with the nursery’s requirement for 50kg of potatoes a week.

Finding a reliable and relatively cheap source was starting to look like an impossible task when Ms Turner had a eureka moment while out shopping. Maybe the answer was right under her nose - if she could only persuade her local supermarket to help. She asked to see the manager of Waitrose on Holloway Road in nearby Islington. He contacted head office, which agreed to supply the school’s food at a 10 per cent discount. That discount, together with bulk orders from wholesalers, has helped Mapledene keep the daily cost of feeding 80 children below pound;2 a head.

The centre is open five days a week, 48 weeks of the year, serving five small meals a day to children aged from six months to five years and with a range of dietary requirements. Keeping so many youngsters fed and watered is a full-time job - one that belongs to cook Sylvia Peters. A typical menu might include home-made pizza, fish and rice, with scones or biscuits as snacks, and plenty of fresh fruit and vegetables.

“Waitrose has been brilliant, so supportive in lots of ways,” says Jan Turner. Apart from providing recipe booklets and cookery workshops for parents, the company bought a food mixer for the kitchen and even paid for Sylvia Peters’s assistant to go to college on day release.

Jan Turner doesn’t know if the diet improves the children’s abilities, but she insists that eating wholesome food can’t do them any harm. “We have the children for the first five years of their lives. We give them five small meals a day. So we are giving them the majority of their food for the first five years of their life. I don’t think it necessarily makes them brighter or better behaved, but it’s part of giving them a better start in life.”

The menu is about 70 per cent organic, Jan reckons. Catering-size packs aren’t available for many organic ingredients, organic fish is hard to find, and the centre is stuck with European Union subsidised supplies of non-organic milk. And not everything organic is appetising - organic crisps got the thumbs-down in tests.

“Some heads have told me, ‘We haven’t got time to do all this - as long as there’s food on the table that’s all that matters’,” says Jan Turner. But with so much so-called fresh food containing pesticide residues - up to a third of cereals, fruit and vegetables, according to research in Europe last year - going organic seems like the wise option.

But the organic message isn’t just something served up on a plate. Children are encouraged to go into the kitchen to see food being prepared and help to take it into the classroom areas - rooms suitably named after seedlings and apples, palms, maples and mangoes - at mealtimes.

Outside, vegetables and herbs grow profusely in between the play areas. Taking inspiration and advice from the renowned medieval herb garden at the nearby Geffrye Museum, Mapledene has recreated a smaller version in its own backyard. Sorrel and tansy, fleabane, feverfew and sweet woodruff have sprung up among the tomatoes, beans and flowers. A couple of hundred years ago, when Hackney was a village outside London, such herbs would have been grown commercially in the area.

Today, Hackney is a very different place and the Mapledene centre is hemmed in between newly built houses and flats. Greenery is thin on the ground. But Jan Turner is anxious that the children and families who come here - many of whom have no garden - shouldn’t lose sight of the natural world. Using the same powers of persuasion that sealed the Waitrose deal, she got the council to agree to release a derelict plot of land next door to the school. She plans to transform it into a garden that will be sensory and educational - and organic.

All the children old enough to wield a spade will be getting involved. “They love that physical thing of going out in the garden and digging,” says Jan Turner. “It’s about understanding that there’s a link between what we put in the earth and what we get out of it.”

Ideas from Mapledene nursery and 20 other schools around Britain featured in the prizewinning Growing Schools garden (see ‘Friday’ magazine, June 28) at the Hampton Court Flower Show last month. The garden is being recreated at the Environmental Curriculum Centre, Eltham, in the London borough of Greenwich. The centre is a nine-acre wildlife site with a rich range of habitats. The charity Learning through Landscapes has its London office at the centre and the garden will be open to schools by appointment. Further information: www.schoolsgarden.org.uk; www.ltl.org.uk. Jan Turner: jturner@mapledene.hackney-lea.org.uk