A garden of earthly delights

ADAM and Eve were expelled from the Garden of Paradise for eating the forbidden fruit of the Tree of Knowledge. Could we, their descendants, get back to paradise by doing the same thing; seeking knowledge? If we are to make the Earth healthy and wholesome again, we need to know how to do it.

So reasoned a group of enthusiasts in 1994 when they dreamed of building an enormous garden, the likes of which had never been seen before. A series of model ecosystems would explore the relationship between people and plants, worldwide. “Cynicism does not seem to have made the world a better place, so we thought we would try innocence,” declared Tim Smit, re-discoverer of the Lost Gardens of Heligan and the driving force behind the aptly-named Eden Project.

The site chosen for the new paradise was a gigantic china clay-pit, 5km northeast of St Austell in Cornwall. This huge hole in the ground resembles a steep-sided meteor crater and encloses an area sufficient for 35 football pitches. Deep within it, and along its sides, a series of ‘biomes’ have been created, each featuring the plants of a particular type of climate. Architect Nicolas Grimshaw’s design was inspired by phyllotaxis, the arrangement of leaves on the stem of a plant. The focus is on plants of value to humans for food, building materials, clothing or medicine.

The biome for the temperate regions of the Earth, which includes most of Europe and North America, is outdoors on the south-facing slopes. All the familiar vegetables grow here. Plaques give interesting insights into the ecology and uses of the plants. Cotton growing, for example, consumes a quarter of the world’s pesticides. The average family house produces 4.2 tonnes of CO2 annually. An average-sized car generates about 4.4 tonnes while food production processing and transport account for eight tonnes. There would be huge savings on emissions, Eden tells us, if people grew their own food. The rainforest and Mediterranean biomes are in glasshouses, which resemble giant golf-balls. The domes are geodesic, which means they are spheres made of flat hexagonal plates. The plates used at Eden are of tough plastic; glass would have been fragile and dangerous. Geodesic structures, even when made of light material, are extraordinarily robust. The dome of the tropical rainforest biome encloses 1.6 hectares of sloping ground and is 55 metres high. It is the largest glasshouse in the world but such is the depth of the quarry that the sphere is invisible from the surrounding countryside.

Specimens of the some of the world’s most useful plants, including bamboo palms and coffee, grow in the tropical biome. Rice, cultivated for 15,000 years, feeds more than half of the world’s population. Despite extensive precautions to exclude them, some exotic creepy-crawlies got into the facility, so insect-eating birds and reptiles have been introduced to control them. The sulawesi white-eye is a particularly endearing little bird. The water requirements of this enclosed rainforest are enormous but here the site comes into its own. It is 15m below the water table and would flood if left to its own devices. On a typical wet day, about 200 million litres of rainwater flow into the crater. The run-off from the giant spheres is captured and pumped into the biomes. Rainwater is used for cleaning and to flush toilets. Only windmill-generated electricity is consumed and the courtesy buses, ferrying people between the crater and the car-parks, run on bio-fuel. The plants of the Mediterranean, South Africa and California feature in the third biome. Here, plants must cope with dry soils and hot sun. Shrubs are more common than trees, whereas in the tropics, the reverse is the case. This is also the realm of the olive and the vine, citrus fruits and peppers.

Eden draws more than a million visitors each year. During the two days I spent there, the numbers were not excessive but in high summer traffic jams and queues can be expected. This extraordinary institution must be visited.

* www.edenproject.com.