September 2026

LENs West Wales collaborates with WWF Cymru for seaweed fertiliser trial

For centuries Welsh coastal farmers and gardeners used seaweed as a fertiliser to help grow plants and vegetables, but its use diminished as modern, synthetic fertilisers took over.

Trials now taking place on LENs-funded farms in Carmarthenshire and Pembrokeshire are looking at how seaweed biostimulant may support farmers to move away from costly, imported nitrogen fertilisers. Seaweed biostimulant can help regenerate soil health by supporting nutrient uptake as part of an integrated programme to support plant health and yield. Using locally farmed and processed seaweed, the trials hope to show that farmers could have a lower emission option that can mitigate against the effects of more frequent global shortages, extreme weather and climate change.

WWF-UK is working with local farmers to trial the effectiveness of farmed seaweed as a biostimulant, with the product being provided by Wales’s first shellfish and seaweed farm, Câr-y-Môr. The trial has been designed in collaboration with WWF-UK by Puffin Produce and Pembrokeshire Creamery, working with farms from both supply chains to understand how artificial nitrogen fertiliser can be reduced in dairy and potato farming.

The farms are all currently part of LENs West Wales, which brings organisations together to co-fund and implement regenerative agriculture and nature-based solutions to drive landscape resilience. LENs West Wales is funded by Puffin Produce and Pembrokeshire Creamery.

This biostimulant product, made in Pembrokeshire and derived from native seaweeds (sugar kelp, oarweed and furbellows), draws on both modern innovation and ancient practices.

“The long history of using seaweed as a sustainable, natural product in multiple ways continues in Wales, and we’re proud to be part of innovative work in Pembrokeshire and Carmarthenshire. Nature offers the solutions to some of the challenges facing our farmers, such as becoming more resilient in the face of climate change, as well as reducing agriculture’s impact on our rivers and seas. We look forward to exploring the evidence and supporting the development of a sustainable, home-grown seaweed industry in Wales.”

Ollie Parker, Regenerative Ocean Farming Project Manager, WWF UK

Unlocking the power of seaweed

Seaweed is natural, sustainable, versatile and resilient.

It grows without input – no fertiliser or feed – and its multiple applications include food, textiles, cosmetics, supplements and animal feed. These have contributed to a growing global seaweed industry and to inspirational initiatives like this one in Wales.

How will the trials be evaluated?

LENs will carry out the monitoring, reporting and verification of the trials by taking soil samples for broad nutrient analysis. This will help us understand how the farmed seaweed biostimulant has impacted soil health. Crop quality and yield will be measured against an untreated control parcel of the field to assess effectiveness.