Monday morning rituals don't come much better. As their classmates are shepherded into assembly, a handful of pupils at Woodingdean Primary School are given leave to potter around the garden, dousing parched plants with water after one of the hottest weekends of the summer. In her blue dress and dainty shoes, Elizabeth Aloof, 10, resembles a latter-day Alice in Wonderland as she tips a watering can over roses and Bugs Bunny carrots in a courtyard groaning with vegetables. Nearby, Alfie Saunders, also 10, is tending some florid cabbage tops. He breaks off to check on the pots lining a window-sill in an adjacent classroom, where tomatoes and aubergines jostle for the sun's rays.
Blessed with generous grounds and sweeping views over the point where the Sussex Downs taper into Brighton, Woodingdean occupies a rare location. But what it shares with thousands of primaries, from rural Scotland to inner London, is a growing enthusiasm for including gardening in its timetable – and using outside spaces for lessons across the National Curriculum.
This renaissance in outdoor teaching has been fostered by the Campaign for School Gardening, launched by the Royal Horticultural Society two years ago this September. In recent months, the scheme has secured sponsorship from Waitrose, a media partnership with The Independent on Sunday, and the support of television gardener Alan Titchmarsh, who this spring pledged 100 annual grants of £500 to schools that move beyond seed-sowing and fruit-picking to integrate horticulture into learning. The RHS's original ambition was to reach 18,000 of Britain's 23,000 primaries by 2012, but it has already enlisted 9,000 and now expects to hit its target next year. Ruth Taylor, the RHS head of education, says: "It's our aim to get the Government to recognise that growing plants is as much a key skill as cooking."
The society concedes the unprecedented uptake of its scheme has been encouraged by recent changes to the primary school curriculum, which have seen the creative learning principles underpinning early-years foundation-stage extended to older age groups. New nutritional standards for primary school lunches, following Jamie Oliver's campaign, have also focused minds.
Despite this, a survey of 500 primaries carried out by the RHS in 2007 indicated an alarming under-use of school gardens: of the 300 that had them, nearly half admitted using theirs less than once a month.
Today the picture is very different. Taylor says: "Initially schools used their gardens for science and promoting healthy eating, but now they're more creative, using them for everything from storytelling to yoga." There's no shortage of creativity at Woodingdean. As Alfie and Elizabeth wander through a trail of flowerbeds designed by a local landscape gardener, they meet a group of reception children arranging chunks of tree bark into images of giants. Surveying the spectacle from an "outdoor classroom" of log stools are Lauren Johnson, a Year One teacher and personal social and health education (PSHE) co-ordinator, and Mark Griffiths, who teaches Year Five and doubles as expert on all things green. "Teachers inspired by the outdoors can make loads of links to the curriculum, says Johnson. "I took mine out to do observational drawings last week."
Every inch the gardener, with his windswept hair and mud-spattered shorts, Griffiths has even been known to find uses for courgettes in maths. "Rather than sitting in a classroom, you can look at a raised bed and say, 'A courgette plant needs this much space to grow: let's measure the area'."
Educational outcomes can be found throughout the school: reception class walls are festooned with vegetable-print paintings and leaves and twigs pupils collected on a recent Explorer's Day. On a table lies a portfolio chronicling the garden's transformation, from bulldozer to harvest. But what do the pupils make of the moves to replace electronic whiteboards and computers with the materials of nature?
"I like getting dirty in all the mud!" grins an immaculate Elizabeth, adding that attending Tuesday night's allotment club has inspired her to convert her family to the joys of horticulture. "I dug up my patio to make vegetable patches. We always did a bit of gardening but now we've got purple-spiked broccoli and a cherry tree coming through the decking."
Alfie, loud red sunglasses slung around his neck, says what he most enjoys about gardening (besides "digging things up") is tasting the fruits of his labours. At school, produce is distributed in one of two ways: at end-of-term Big Pulls, when allotment club members take home their share of the harvest, and weekly lottery-style draws. "I won a pepper on Friday!" Alfie announces.
Not all schools are as equipped for gardening as Woodingdean. Set in a rolling landscape of fields and allotments, it serves a relatively well-heeled catchment area. Whenever Griffiths needs £100 for seeds or trowels he can rely on the parents, teachers and friends association to raise it ("they sold ice-creams in the playground on Friday").
But what has the campaign done for poorer communities? Pirton Hill Primary School in Luton draws three-quarters of its 530 pupils from Hockwell Ring, a multi-ethnic district which is one of the 20 per cent most socially deprived areas in England and Wales. The deputy head, Emma Woollon, started a basic garden three years ago, before stumbling on the RHS scheme via its website. The school is now racing to qualify for a £500 Alan Titchmarsh Award so it can replace the ageing second-hand tools donated by staff.
Woollon says the process of nurturing their own crops has given some children their first insight into basic dietary issues. "Many of them eat junk food and have no understanding of where food comes from, apart from packets," she adds. "At our last Ofsted inspection, some pupils didn't know milk came from cows."
Gardening has also helped with behaviour. "One child used to walk out of class the whole time," adds Woollon. "He went out one day to lay compost with the gardener. He hasn't got an adult male role model in his life and he responded well."
The issues with which Pirton Hill is wrestling mirror concerns that moved Alan Titchmarsh and his wife, Alison, to set up their Titchmarsh Gardens for Schools Trust in 2002. "I get angry when people put gardening in a little box," says Titchmarsh. "Gardening is a good thing socially, spiritually, and physically. It ticks so many boxes in terms of educational development, and it's wonderfully benign."
Does he think governments should do more to promote school gardening? "I do. School is about the three Rs but also about preparing you for the world outside. Children are evangelical about being green, but often on the negative side – 'don't do this, don't do that'. What about things you can do?"
A fertile campaign
* The RHS Campaign for School Gardening began in September 2007 to promote the use of gardens to teach the National Curriculum
* Schools are given free seeds, teacher training and rewards for progressing through five stages – from setting up their gardens to sharing them locally
* Up to 100 Alan Titchmarsh Awards of £500 are given each year to the first schools to reach benchmark four