Catalyst Farming is contributing to a new, large-scale trial to test a growing but still uncertain idea in sustainable agriculture: can seaweed-based biostimulants help reduce the need for synthetic fertiliser, without compromising crop yield or quality?
The project, coordinated by WWF and involving a consortium of farming and research partners, builds on a pilot study from 2024. Its aim is not to replace fertiliser entirely, but to explore whether biostimulants derived from UK-farmed seaweed could make fertiliser use more efficient and thereby support both cost savings for farmers and a lower environmental footprint for food production.
While the concept is promising, evidence from commercial-scale field trials in UK conditions is still limited. This project aims to change that.
What Are Biostimulants and Why Seaweed?
Seaweed biostimulants are products made from macroalgae that contain a mix of micronutrients, organic compounds, and small amounts of NPK. These aren’t fertilisers in the conventional sense, but are believed to improve plant health, boost root development, and help crops take up nutrients more efficiently.
If that’s true, it might allow farmers to apply less synthetic NPK while maintaining yields. That’s the theory this trial sets out to test.
The project will compare biostimulants from three sources:
- Sugar kelp (Saccharina latissima) – farmed in Norfolk
- Winged kelp (Alaria esculenta) – farmed in Scotland
- Ascophyllum nodosum – a commonly used wild-harvested seaweed
Each will be trialled in combination with different fertiliser rates on spring barley and potatoes at the Holkham Estate in North Norfolk.
Trialling Under Real Farm Conditions
Catalyst Farming’s role is to lead the practical implementation of the trial, ensuring it reflects commercial farm realities. Over two years, the trial will include 96 spring barley plots and 48 potato plots, with multiple fertiliser and biostimulant combinations replicated and randomised for statistical robustness.
“Our aim is to take a hard look at how seaweed biostimulants behave in real-world settings,” said Dominic Swan from Catalyst Farming. “There’s a lot of buzz about their potential, but we want to understand whether that translates into tangible results in terms of reduced fertiliser needs, economic viability, and soil health.”
Scientific Rigor, Open Results
The project is also funding two PhD students at the University of East Anglia to study both the mechanisms behind biostimulant function and the sustainability of production methods. Cefas will lead life cycle assessments to measure carbon and nutrient impacts.
Importantly, all findings will be made open access—available to farmers, agronomists, and policy makers—regardless of whether the results support or challenge the current enthusiasm around seaweed.
There’s real potential here, but we’re not here to promote a product, we’re here to test a hypothesis. If seaweed can reliably support even modest reductions in fertiliser use, that’s a meaningful step in the right direction for both farm resilience and environmental impact, but we need good data before drawing conclusions.
Looking Ahead
Results from the first growing season will begin to emerge later this year, with full conclusions expected by 2027. In the meantime, the project forms part of Catalyst Farming’s wider exploration of regenerative practices that combine economic viability with long-term soil and ecosystem health.
