“There’s not many jobs where you get to be a sea gardener,” says Dr Oliver Thomas, senior science officer at Project Seagrass. He’s looking for flashes of eel grass that have survived the winter in the wide golden sand of Penrhyn beach on Ynys Môn (Anglesey), in north Wales.
But growing a meadow in the sea is not an easy job. Vast swathes of the gorgeous underwater swards, vital nurseries for fish such as cod, have been wiped out around the UK in the past century. Up to 92% have been lost. Restoring them – and their water-cleaning, carbon-storing, coast-protecting benefits – is a colossal challenge.
“Last October, this was looking great,” says Thomas. “But this winter’s obviously hit it harder than we’d anticipated. It’s rained a lot and it’s been very dark. But I am hopeful it will bounce back. There are roots there.” The mahogany rhizomes poking out are packed with sugars, ready to sprout green shoots as the sun returns.
The goal over several years is to plant 10 hectares, meaning millions of seeds, all collected by hand from the remaining healthy meadows. Getting them in the sand is a lot of work; one volunteer getting her wellies wet is Annabelle Campbell-Priest, 12, who is meticulously squirting the seeds into marked plots using a caulking gun and recycled sealant tubes.
She twists the seed gun carefully after each squirt to seal the seeds in the gloopy sand, repeating the operation hundreds of times and leaving 320 of the pine nut-like seeds in each square metre. “It can be hard work – my back is a bit sore – but it’s always worth it when you know you are doing something good for the environment,” says Campbell-Priest, a seagrass ocean rescue champion from a local school. “The seagrass was really beautiful in October – there was so much of it.”
There is also a hand-pushed seeding machine, which injects multiple squirts as its drum rotates. It’s faster, but less precise, and strenuous work. Rhun ap Iorwerth, the leader of Plaid Cymru and member of the Senedd for Ynys Môn, is one of the volunteers putting his back into it.
“The engagement with young people is particularly important here because these seagrass beds will be theirs to look after in years to come,” he says. “Getting them up close and literally pumping the seed into the sand hopefully will plant something in them too about the importance of what they’re doing.”
Those who have seen a pristine seagrass meadow don’t forget it. “They are amazing,” says Bridget Patterson, a research assistant from Project Seagrass. “There’s lots of fish, crabs, cat sharks, dog whelk eggs … just about everything spends a little bit of its time in seagrass.” Cuttlefish spawn there too, and in some, seahorses hide among the blades.
Crab within an Orcadian seagrass meadow. Photo credit Lewis M Jefferies
“Seagrass is a pretty hardy and resilient plant if changes are slow, but sudden changes are a big threat,” Patterson says. There have been a lot of the latter: new ports and harbours, land reclamation, influxes of pollution, wasting disease outbreaks and the anchor chains of boats scything through the grass have all contributed to the decimation of UK seagrasses.
Restoring the meadows also faces challenges: a summer heatwave coinciding with particularly low tides wiped out one on the Llŷn peninsula in 2025 after exposing the grass to 30C heat. Storms Babet and Ciarán in 2023 wiped out new meadows in the Firth of Forth. Young meadows are also vulnerable. “We have lost a whole plot to Brent geese,” says Thomas. “They love the grass – which would be fine if there was a lot of it.”
Lugworms can also gobble up the seeds before they get established. “Little bastards!” laughs Prof Richard Unsworth, chief scientist to Project Seagrass, looking at the proliferation of worm casts across the beach.
The charity is now planting at sites around the UK. “We’re getting there,” he says. “We’re expanding and we’ve got sites on the Isle of Wight that are full of fish, with birds diving into them for the fish. That’s just lovely to see.” Dale in south Wales also has successful meadows, with cuttlefish using them as nurseries, he says. Other groups are reviving meadows from Plymouth Sound to the Humber to Loch Craignish in Scotland.
The plots that fail are part of the process of learning how to restore the meadows, Unsworth says. “People have been planting crops for thousands of years: that’s why we’re good at it. But we’ve only been planting seagrass for 30-40 years.”
Unsworth’s group alone have carried out more than 70 experiments, testing every variable. Are seeds harvested from subtidal grasses better than those from intertidal varieties? How are they best stored and then revived? What’s the perfect depth and density for the seeds? Does dropping seeds in the water in little hessian bags stop crabs devouring them?
Then there’s the sites. Do locals say there used to be seagrass? How strong are the currents? Centimetre-accurate GPS, drones and temperature-light-salinity loggers are all deployed to find the answers.
“We’ve now got very good knowledge of some factors, some we still haven’t got a clue about, but we’re getting a lot better,” says Unsworth. “However, there is no silver bullet.”
Seagrass breathes oxygen back into the sediment, leading to a flourishing of life under the surface as well as above. Eden Jefferson, a master’s student from Swansea University, is on the beach taking cores to examine back in the laboratory. “There can be worms, shrimps, gastropods – all sorts of weird and wonderful things.”
Getting the first patches of seagrass established is the key, as these engineer the environment by slowing currents and clearing the water so that more can grow. One experiment being tried, dubbed “seagrass hugs” by the researchers, involves planting a protective ring of fully adult seagrasses around a new seedbed.
The restoration in the Wadden Sea in the Netherlands is an inspiration for the team. There it took five to six years of concerted planting before a big win, says Unsworth. There was a commercial seagrass industry there a century ago, with the dried grass used for pillows, insulation and packing. Seagrass in fact has been used by people across the world for thousands of years, from eating the seeds to using the dried blades as clothing and roofing.
Restoration in Wales will benefit people too, says ap Iorwerth: “The sea we’re celebrating here today and the part it can play in literally cleaning up our planet is the same sea that can create real economic benefits, such as fishing and tourism. To me it’s all intertwined.”
Wales is already the first country in the world to have a national action plan to restore seagrass, with a goal of 250 hectares restored by 2030. With Plaid Cymru polling well ahead of Senedd elections in May, ap Iorwerth could be Wales’s next first minister.
“If we succeed in this election, we’ll always be a government right behind our environment and our coastal communities,” he says. “This project is something that we have to see through.”
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