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Millennium Seed Bank Turns 25: King Charles III joins podcast series host, Cate Blanchett, for the launch of Kew’s fourth Unearthed series
King Charles III joins podcast series host, Cate Blanchett, for the launch of Kew’s fourth Unearthed series, Image credit: Royal Botanic Gardens
- King Charles III joins Cate Blanchett to launch the Fourth Season of the Royal Botanic Gardens, Kew podcast ‘Unearthed: The Need For Seeds’, marking 25 years of the Millennium Seed Bank.
- The Millennium Seed Bank keeps more than 2.5 billion seeds from 40,000 types of wild plants.
- Its goal is to preserve plants from extinction and to help scientists study plants, support the recovery of damaged environments, and even help discover new medicines.
His Majesty The King, Patron of the Royal Botanic Gardens, Kew, joins podcast series host Cate Blanchett, Kew’s Ambassador for Wakehurst, for a special podcast ‘Unearthed: The Need For Seeds’, episode launching Kew’s fourth Unearthed series. The podcast was released on 20 October 2025 by the BBC and the Royal Botanic Gardens to mark the bank’s 25th anniversary.
Their conversation with Dr Elinor Breman establishes why it is important to protect wild plant diversity. Millennium Seed Bank holds over 2.5 billion seeds from about 40,000 wild species at –20 °C.
The Millennium Seed Bank
The Millennium Seed Bank (MSB) is a global project for plant conservation run by the Royal Botanic Gardens, Kew. It is located at Wakehurst Botanic Garden in Sussex, England. King Charles III, then the Prince of Wales, officially established the seed bank in 2000.
According to Kew’s State of the World’s Plants and Fungi report, up to 45% of plant species are at risk of extinction. Habitat destruction, climate change, pollution, and invasive species have accelerated the decline of ecosystems that humans depend upon for food, air, and medicine.
The seed bank aims to collect, conserve, and protect the world’s wild plant species for future generations. It currently holds over 2.5 billion seeds from about 40,000 wild plant species, stored at -20 °C in underground vaults. These seeds come from all continents except Antarctica and serve as a safeguard against plant extinction.
The MSB’s work supports restoring ecosystems, ensuring food security, conducting scientific research, and discovering potential medicinal compounds. The bank collaborates with more than 270 organisations in nearly 100 countries to improve seed conservation worldwide. Its collections have helped restore habitats like the chalk grasslands of southern England and areas affected by fires in Australia. The project also supports research on germination, drought tolerance, and biodiversity resilience.
The MSB aims to secure 75% of the world’s threatened plant species by 2030. Cate Blanchett became Wakehurst’s first ambassador in 2024, promoting public awareness of the initiative.
In the past 25 years, the MSB has transformed from a “doomsday vault” into a proactive force for restoration and environmental sustainability. Its mission remains crucial as nearly half of the world’s plant species face extinction due to climate change, habitat loss, and human activity.
‘Unearthed: The Need for Seeds’ podcast
‘Unearthed: The Need for Seeds’, podcast produced by the Royal Botanic Gardens, Kew in partnership with the BBC. It aims to bring listeners closer to the hidden world of plant conservation and seed science. The host, Cate Blanchett, who is the Ambassador for Wakehurst, guides the audience through the important work of Kew’s Millennium Seed Bank (MSB).
This is the largest wild-plant seed collection in the world, located at Wakehurst in Sussex, England. Each episode of Unearthed: The Need for Seeds focuses on a different aspect of seed conservation. It covers topics from collecting wild seeds in tough environments to the latest science used to preserve them for centuries. Listeners meet the dedicated scientists, researchers, and conservationists working at Kew, including Dr. Elinor Breman, Senior Research Leader in Seed Conservation.
The discussions emphasise the scientific significance of seed banking and its cultural, social, and environmental importance in today’s world of climate change and ecological decline.
“I know how absolutely critical it all is, and the destruction of rainforests, the extinction of endless species, which have very likely remarkable properties,” King Charles said.
He also emphasises the urgency of accelerating conservation work, remarking: “I think it’s wonderful what the seed bank is doing, but we’ve got to speed up the process.”
A special highlight of the series is the episode titled “Special Episode: With His Majesty the King,” released on 20 October 2025 to celebrate the 25th anniversary of the Millennium Seed Bank. Recorded at Windsor Castle, this episode includes King Charles III in conversation with Cate Blanchett and Dr Elinor Breman.
For Cate Blanchett, her connection with the seed bank was deeply personal and began by chance.
“I literally had my mind blown by the work that goes on here… and I thought, anything I can do to be connected to it — I found it so inspiring”.
She also expressed her growing awareness of the fragility of natural landscapes:
“There’s an urgency to the work that the seed bank does here in this country. I was shocked to learn that 97% of the wildflower meadows have been decimated. I don’t think it’s something that we quite understand because we look around us and we see so much natural beauty. But we don’t think how fragile it is.”
They reflect on the origins of the MSB, which the King opened when he was the Prince of Wales in 2000, and they discuss how it has grown into a global centre for biodiversity preservation and habitat restoration.
The world’s largest Wild Seed Vault
Hidden beneath the rolling landscapes of Sussex, the Millennium Seed Bank is a modern ark for plant life.
The seed bank holds over 2.5 billion seeds from around 40,000 wild plant species, sourced from every continent except Antarctica. Each specimen is meticulously cleaned, dried, and stored at –20 °C to ensure it remains viable for centuries.
The mission is straightforward yet monumental: to prevent the extinction of plant species and ensure that they can be reintroduced into the wild when needed. What began as a “doomsday vault”, a global backup to safeguard the world’s flora, has evolved into a dynamic hub of restoration and scientific collaboration.
The MSB’s work extends well beyond the vault. Its seeds have already been instrumental in reviving damaged ecosystems, from the chalk grasslands of southern England to the fire-ravaged landscapes of Australia.
The technology behind the MSB vault
MSB is an underground temperature-controlled vault, situated more than eight metres below the surface to protect it from environmental fluctuations, natural disasters, and human interference. The entire facility is constructed with reinforced concrete and insulated chambers to maintain constant low temperatures and humidity levels.
Every seed that enters the Millennium Seed Bank follows a precise process rooted in decades of botanical science. Field teams collect specimens from habitats ranging from tropical rainforests and arid deserts to alpine slopes.
Once at Wakehurst, the seeds are stored at -20°C, which is a great temperature that slows down metabolic activity and delays ageing. Before reaching the vault, the seeds go through a careful preparation process. They are cleaned, dried in a controlled environment at 15°C and 15% relative humidity, and packed in airtight, moisture-proof containers made of aluminium foil.
The MSB uses cryogenic and low-temperature storage methods to extend the life of seeds that don't survive traditional freezing. Some tropical and recalcitrant seeds, which are sensitive to drying out, are preserved using cryopreservation. This technique cools biological samples to extremely low temperatures (below -150°C) with liquid nitrogen.
Beyond the physical setup, the MSB uses advanced genetic and viability testing methods. Scientists regularly run germination tests to check the health and fertility of stored seeds. They also use DNA sequencing and molecular profiling to study genetic diversity and evolutionary traits.
However, the MSB’s mission goes beyond storage. Its scientists collaborate with over 270 partner institutions across nearly 100 countries, sharing expertise and training local botanists to establish satellite seed banks.
The MSB Impact
The implications of seed preservation extend far beyond conservation. Many modern medicines, from cancer treatments to pain relief, originate from plant compounds. Each species lost to extinction could represent a missed medical or agricultural breakthrough.
Dr Breman and her colleagues at Kew view the MSB as both a scientific archive and a source of future innovation. By maintaining genetic diversity, researchers ensure that plants may one day provide solutions to challenges such as climate resilience, food security, and disease treatment.
The MSB’s collections have already contributed to research in ecology, genetics, and pharmacology. In some cases, stored seeds have been used to study resistance to drought and disease, offering insights that could support sustainable agriculture in developing regions.
Global partnerships
The Millennium Seed Bank is the cornerstone of an international network spanning almost a hundred countries. Through the Millennium Seed Bank Partnership, Kew works with more than 275 organisations, including universities, botanical gardens, and conservation groups, to collect and protect the world’s most threatened plant species.
Together, they have safeguarded seeds from ecosystems ranging from the rainforests of South America to the savannas of Africa. The aim is not only to preserve what exists but to prepare for the future.
By 2030, the MSB hopes to cover 75% of the world’s threatened flora, expanding both its physical collection and its digital catalogue. This requires continuous international collaboration, funding, and public awareness.
King Charles and Blanchett’s public advocacy plays a crucial role in achieving that. By drawing global attention to the quiet, meticulous work of Kew’s scientists, they help ensure that the value of biodiversity remains visible, not hidden away in underground vaults.
