Our story

The Eden Project was built in a 160-year-old exhausted china clay quarry near St Austell, in Cornwall. It was established as one of the Landmark Millennium Projects to mark the year 2000.

Interior of Eden Biome before plants were planted

From the beginning...

While restoring the Lost Gardens of Heligan in the early '90s, Tim Smit became fascinated with stories that connected plants to people and brought them alive. He enlisted the help of Philip McMillan Browse (former Director of RHS Wisley and Horticultural Director of the Lost Gardens of Heligan) and Peter Thoday (former President of the Institute of Horticulture), to put together a team of expert horticulturalists.

Let it rain...

In the first two months of construction it rained every day; 43 million gallons of rainwater drained into the pit. This prompted the engineers to come up with a magnificent subterranean drainage system that now collects all the water coming on to the site. We use it to irrigate our plants and flush our loos, while rainwater that falls on the Biomes is used to maintain the humidity inside the Rainforest Biome. Today almost half of our water needs are provided from water harvested on site.

A bit about the Biomes...

You could fit the Tower of London in the Rainforest Biome. The Guinness Book of Records heralds the Biomes as the biggest conservatories in the world. Building these ‘lean-to greenhouses’ on an uneven surface that changed shape was tricky: ‘bubbles’ were used because they can settle on any shaped surface – the architect got the idea while washing up!

Soil and climate...

With help from Reading University we made over 83,000 tonnes of soil, because we didn’t want to deprive anyone else of theirs and because we wanted to get the recipes right. The mineral component came from local mine wastes: sand from IMERYS china clay works and clay from WBB Devon Clays Ltd. In the Biomes, composted bark provided the organic matter component because it needed to be long lived. The rapid growers in the Rainforest Biome needed a rich organic soil capable of holding lots of water and nutrients while the slower growers in the drier Mediterranean Biome used a sandy mix which held less of both. A specialist nutrient-free mix was used in the South African Fynbos, where fertile soil is toxic to some of the plants. Outdoors, we went for composted domestic green wastes. The ingredients were mixed with a JCB in a nearby clay pit, and Wiggly Wigglers worms helped dig and fertilise the new earth. Our soils help to show that environmental regeneration is possible.

The covered Biome climates are constantly monitored and are controlled automatically. In the Rainforest Biome automated misters moisten the air (90% relative humidity at night, and down to 60% in the day) and ground-level pipes irrigate the soil so you don’t have to put up with the rainforest’s 1,500 mm (60 inches) of rain a year. Our huge waterfall uses recycled water and keeps humidity high. In the Mediterranean we keep it drier. Vents are often open, even during cool periods, to reduce humidity and therefore fungal problems. The main heating source for both Biomes is the sun. The back wall acts as a heat bank, releasing warmth at night. The two layers of air in the triple-glazed windows provide insulation. Extra heating comes from the big grey air-handling units which also help circulate the air on hot days.

Plants and wildlife...

We’ve planted around 1 million plants of just under 4,000 taxa (species and cultivars). Most are not rare, except for the few that tell stories of the need for conservation, neither were they taken from the wild. Many were grown from seed in our nursery, others came from botanic gardens, research stations and supporters, mostly in Europe and the UK. Once established, the big ’uns in the Rainforest Biome are pruned by abseilers or from a cherry picker. Our green team are ‘extreme gardeners’; planting on near-vertical banks presents something of a challenge.

Some of our plants are insect-pollinated, others wind-pollinated. In an emergency we use a paintbrush! We only have to pollinate the flowers if we want them to produce seeds. Our rigorous healthcare programme, using isolation houses at Eden’s nursery, catches pest and disease problems before they reach the pit. In the pit our integrated pest management system uses cultural methods (removal of infested plant parts), ‘soft’ chemicals (soaps and oils) and 33 different types of biological control (bugs that eat bugs). We give some of them a lift up to the canopy in the Rainforest Biome in little bamboo pots on string pulley systems. We also have some birds and lizards in the Biomes which not only look good but also eat their fill of pests. UV lightboxes catch pests and monitor their numbers so we can keep an eye on everything.

Eden staff landscaping with soil


Builder in hard hat and high-vis vest in front of Biome at night

How we built Eden

Watch our timelapse video


Key milestones

Helium balloon flying in Rainforest Biome

From clay pit to world-famous visitor attraction and charity, see how our story unfolds.

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Our charitable work

People with tattooed arms planting trays of green, grassy plants

Find out how we work to empower people, regenerate places and look after the environment

See what we do