Meet cotton’s replacement: Sphagnum moss

Three hundred years ago a walk across Cambridgeshire would mean crossing a large area of marsh lands known as The Fens. Before industrialisation, high sea levels and the deposition of marine sediments had the effect of slowing the movement of water off the land, leading the rivers to flood and laying the deep peat soils of what was known as the “Black Fens”. 

Today, more than 99% of the original, ancient wild fen has disappeared. Extensive drainage projects in the 17th century emptied the wetlands, converting over 1,500 square miles into agricultural land for commercial crops. The drainage isn’t just a loss for biodiversity and wildlife, but also for carbon sequestration. 

Peat, the rich organic soil formed of decomposed plant material found in fens, is one of the world’s most powerful carbon sinks. Although peatland covers less than 3% of the earth’s surface, it stores roughly 30% of all land-based carbon. Over the past 300 years, what was once fenland has been transformed into giant fields of monoculture for the cultivation of commercial crops like potatoes and wheat. Much of the wheat sold doesn’t go to human consumption, but to feed livestock. The result is an unsustainable farming practice that increases carbon output and depletes the peat soil. 

That is, until now. 

In 2000, five organisations came together for an ambitious 100-year project to restore and connect 14 square miles of wild fen between Peterborough and Huntingdon known as The Great Fen. Twenty years into the project and over half the territory has been rewilded. The area now supports threatened wildlife such as otters and bitterns and has connected local communities through new miles of footpath. The wetlands also act as a natural flood defence, soaking up water after heavy rainfall to protect surrounding towns and farmland. 

Credit: Kerry Case

One of the greatest contributions is the reduction of peat loss, which is now saving hundreds of thousands of tonnes of CO2 from being released each year. While this is a step forward, the UK continues to lose peat soil at an alarming rate of 2cm per year. In East Anglia, most of the fens have been drained for agriculture to produce salad crops. Convincing farmers to rewet lands to turn them back into fens will require the cultivation of lucrative crops using “wet farming” techniques. 

On the Great Fen scientists are researching plants that can be grown in water. Paludiculture, as wet farming is known, is the productive use of wet peatlands for the cultivation of commercially successful crops grown in conditions that maintain the peat soil. The Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire (BCN) has created the UK’s first field-scale trials of wet farming to test new crops for food, healthcare and industry. Brian Eversham, Chief Executive of The Wildlife Trust BCN, says the most successful candidate is probably one of England’s oldest plants: sphagnum moss. 

Some of the strands of the sphagnum moss could be 8,000 years old. The moss has immense potential as a renewable substitute for horticulture peat due to its high-water retention and acidity level. When restored to damaged moorlands, sphagnum can reduce peak streamflow by 65%, acting as a natural buffer against flooding. It is also a natural sponge for soaking up carbon, responsible for roughly 50% of carbon accumulation in peatlands. The trick is finding a commercial use for it. 

“Sphagnum moss has historically been used as a wound dressing,” explains Eversham. “It grows in water-saturated areas and, when dried, becomes highly absorbent with natural antiseptic properties. Since the 1960s, the pharmaceutical company Johnson & Johnson has held a patent for its use in sanitary products but cannot exercise it due to a lack of supply. Whoever cracks large-scale cultivation stands to make significant profits.” 

He adds that one of its greatest opportunities lies in replacing cotton in bandages, a crop with a heavy environmental footprint. “Sphagnum would be more lucrative and could replace cotton, which is very damaging to the planet. If you can switch to a carbon positive crop, that would be an amazing transition.” 

Beyond its environmental and commercial promise, sphagnum moss also carries significant medicinal potential, much of which remains underexplored in modern healthcare. Its historical use in wound care, noted by Eversham, was not incidental. During the First World War, when cotton supplies were scarce, sphagnum moss was harvested in large quantities and used to pack wounds. Its structure allows it to absorb many times its weight in liquid, helping to keep wounds dry, while its natural acidity creates an environment that inhibits the growth of harmful bacteria. 

This combination of absorbency and antiseptic quality is rare in natural materials. Unlike synthetic dressings, sphagnum is biodegradable and does not rely on intensive industrial processing. Researchers today are revisiting these properties with renewed interest, particularly as the medical field looks for more sustainable and effective biomaterials. There is growing curiosity about whether sphagnum could be adapted for modern wound care, including dressings for burns, chronic ulcers and post-surgical recovery. 

The moss also contains compounds such as sphagnan, a naturally occurring carbohydrate polymer that has been shown to have antimicrobial effects. Early studies suggest that these compounds can disrupt bacterial cell function, reducing infection risk. This opens the door to applications not only in dressings but also in coatings for medical devices or even as a component in new types of antibiotics, at a time when antimicrobial resistance is a growing global concern. 

Credit: Brian Eversham

The challenge, as Eversham notes, is supply. Without a reliable system to cultivate sphagnum at scale, its commercial and medicinal potential cannot be fully realised. This is where wet farming becomes critical. By growing sphagnum on rewetted peatlands, farmers could produce a high value crop while simultaneously restoring ecosystems and locking carbon into the soil. 

If successful, this approach could reshape not only agriculture in regions like East Anglia but also supply chains in industries ranging from healthcare to textiles. A material once gathered by hand from wild bogs in the Medieval era could become a cornerstone of sustainable production in modern times.