Sponsor the sea.
Feed the land.
One payment. A seaweed farm grows a metre of rope for a season. The harvest goes free to a land farm down the coast. Both are measured, both are paid, and you see exactly where your money went.
Three parties. One payment.
We are better at connecting farms and proving what happened than at running them ourselves, so that is the part we do.
You sponsor metres of rope
Pick a farm. Pick how many metres. From a single metre as a gift to twenty kilometres across six countries for a corporate programme.
A seaweed farm grows it
A licensed grower seeds, tends and harvests your rope through the season. They are paid their own price - which they set, and which we publish.
A land farm nearby puts it to work
Wet seaweed goes straight from harbour to field. Soil conditioner, structure, trace minerals, or trial feed. No drying, no pyrolysis, no freight across Europe. That is a large part of why the numbers work.
We measure it and tell you
Yield, habitat, soil and farm income - assessed against The Holdfast Standard and signed off by an independent academic partner, not by us.
Seeded in October. On a field by June.
Your rope has one season and three stages. You see all three, filmed at the farm that grew it.
Seeded twine goes out on longlines between October and December, once the water drops below fifteen degrees. Your metres sit on a named line at a named site.
Six to eight months in the water. Around four kilograms of fresh weight per metre, and a habitat that fish, crustaceans and invertebrates find on their own.
Lifted between April and June and spread wet on a land farm within forty-eight hours. No drying, no long freight. Soil sampled before and after.
Every farm sets its own price. We add ours on top, in the open.
There is no single national rate, because there is no single national cost. A croft-scale operation on Loch Erisort and a hundred-hectare site in Bideford Bay do not have the same economics, and pretending otherwise is how you end up subsidising one farm with another. So each farm publishes its own rate per metre. Our network fee sits on top of it and covers verification, haulage coordination, reporting and the platform. If a farm prices itself out, little sells there and nobody has committed anything.
What we already know works.
Everything below is measured from our own operations in Mulroy Bay, Donegal. It is a small base, and we would rather show a measured one than a large estimated one.
Sea temperatures at the Mulroy site averaged 17.5°C against a 12.9°C long-run norm during the 2024 season, which suppressed yield. We publish that too.
Choose the coast you care about.
Sixty-four licensed seaweed operations exist across the UK and Ireland. We are building relationships with the ones that can take sponsorship money and turn it into rope in the water this season.
Mulroy Bay Kelp
Our original site and the one every number on this website comes from. Five seasons of sugar kelp on a sheltered Atlantic inlet, with harvest going to dairy and tillage farms within thirty miles.
Kelp Crofting
Founded by a marine scientist, run at croft scale on the south coast of Skye. Already publishes its own biodiversity and soil data, which makes it the easiest farm in the network to verify.
Câr-y-Môr
Wales' first commercial-scale seaweed and shellfish farm, owned by more than three hundred local members. The clearest example of a coastline sponsoring itself.
The coasts we can put a rope on.
Sixteen sites shown here, from the farm we run ourselves to the ones still being assessed. Each pin carries its Holdfast score. Select one and the dashed line shows the land farm that takes its harvest.
The map needs an internet connection to load its tiles. The farm list beside it still works.
Teal pins score 8.0 or above, cyan pins between 5.5 and 8.0. Outlined pins are still in assessment and are not open for sponsorship. Locations are indicative in this concept build.
A certificate, then the evidence behind it.
Every sponsor gets a named certificate with the farm, the metres, the serial and the season on it. It is the front page of something longer: the verified report that lands the following summer with the yield, the habitat count, the soil results and the farm income.
The serial resolves to a public record of that rope, so a recipient can check it themselves rather than taking our word for it.
See a full certificate
CK-24-MUL-08412
Season 2024/25
50 metres of rope, Mulroy Bay
Standard
2025
The Holdfast Standard
Sponsorship without proof is a donation with better photography. The Holdfast Standard is how a farm earns its place in this network, and how it can lose it.
Each farm is scored across three pillars on evidence we collect on site, not on a self-assessment form. Scores are reviewed annually and signed off by an independent academic partner. A farm scoring below 5.5 out of 10 does not go on the website.
How scoring works
Ocean
What the rope does for the water it hangs in.
- Species recruitment on and around the line
- eDNA sampling, start and end of season
- Habitat area created per metre
- Licence compliance and site condition
Land
What happens after the harvest comes ashore.
- Tonnage delivered and distance travelled
- Soil organic matter, before and after
- Yield or input-substitution effect
- Methane trials where feed is the end use
People
Whether the money actually reaches the coast.
- Share of sponsorship paid to the farm
- Jobs and seasonal hours supported
- Ownership structure and local control
- Land farm benefit, valued and stated
Sponsor where you actually operate.
Beyond value chain mitigation tends to land better when it is near something. A distribution hub in Rotterdam and a data centre in Dublin are not obviously helped by a tree in Peru.
Pair a Farm
Match a farm to a site, a region or a market you operate in. You get the farm, its farmer, its land partner and its annual Holdfast Standard report, named and yours for the term.
Employee schemes
Metres as a joining gift, a long-service marker or a team allocation staff choose themselves. We handle the fulfilment and the certificates; you get one invoice.
Biodiversity bundles
Ropes left in the water rather than harvested, monitored as habitat across a full cycle. For funders whose interest is the ecosystem rather than the tonnage.
Research partnerships
Co-funded trials with Bournemouth, UCL, Graz and ATU on methane reduction, soil carbon and biohybrid monitoring. Grant-eligible, and how the Standard keeps improving.
“We have raised more than a quarter of a million pounds through sponsorship alone. No credit sales, no investment rounds, no permanent operations team. The demand was never the problem.”Carbon KaptureAnnual Report 2024
The honest answers.
Is this a carbon credit?
No. Sponsoring a metre of rope is not a verified carbon credit and cannot be used against a science-based target. It sits in beyond value chain mitigation: real, measured, local good that happens outside your own footprint.
The carbon science on cultivated kelp is genuinely unsettled. What is clear is that the seaweed grows, the habitat forms and the land farm gets a delivery.
When do I get my report?
There is one growing season a year and the kelp decides when it runs. Orders close on 31 August because a hatchery needs six to twelve weeks to grow seeded twine before it can go to sea, and the season starts when the water drops below fifteen degrees, around September to November.
So: you sponsor by August, lines are deployed in October, the harvest is lifted between April and June and goes to a land farm within forty-eight hours, and your verified report lands the following summer. It is a slow product, and it seemed better to say so.
Why do prices differ between farms?
Because costs differ between farms. Boat time, licence area, labour, distance to the land partner and exposure all move the number. Each farm sets its own rate and we add a transparent network fee on top. We would rather show you a £24 metre in Skye and an £18.50 metre in Donegal than average them into a fiction.
What happens if the crop fails?
It sometimes will. Storms, fouling, warm water. Every sponsored metre is covered by crop insurance and redeployed at the same farm the following season at no further cost to you. You get told what happened and why, in plain language, in the annual report.
What does the land farmer pay?
Nothing. The harvest is delivered free. That is deliberate: the biggest barrier to seaweed as a soil amendment is that farmers will not pay for an input they have not seen work on their own ground. Sponsorship removes that barrier, and the before-and-after soil data is what eventually creates a market that does not need sponsors at all.
Who checks any of this?
Not us alone, which was a weakness in the earlier version. Holdfast Standard scores are compiled by us and reviewed annually by an independent academic partner. We publish the methodology, the data points and the farms that did not make the cut.
Do you still grow seaweed yourselves?
Only at Mulroy Bay, and mainly as a research and demonstration site. Running farms and running a network are different businesses, and the first one is not our strength. The growers in this network are.
Pick a coast. Put a rope in it.
One metre as a gift, or twenty thousand across the regions your business touches. Same model either way. Practical, decentralised and values-led - rooted in action, not abstraction.