Fibre Flax Variety Trials in Scotland: Assessing Performance for Sustainable Textiles

Intro

Flax was once a thriving agricultural crop in Scotland, grown to produce linen. But with the dawn of the industrial revolution, textile production was outsourced overseas, and the industry declined. Today, a growing demand for sustainable textiles, along with flax's minimal need for chemicals and water, is driving a renewed interest in the crop. However, growers lack sufficient information on growing and selling flax for fibre in a modern UK context.

The Challenge

The UK currently relies on imports for most of its flax, with 80% of the world's flax being grown in Belgium, France, and the Netherlands.
There is little recent research on how modern varieties perform in the country’s soil types and climate. To re-establish domestic production, it is essential to test these new varieties under UK conditions.
Flax provides a range of benefits for soil structure, and there is a growing market for regenerative textiles, but without sufficient information growers cannot access these benefits.
Flax processing is currently outsourced, which is expensive and only possible in large quantities. To make flax-fibre production viable for small to medium-scale growers, local processing capabilities need to be developed.

The Solution

A group of growers formed a network aiming to re-establish a regenerative textile industry in the UK, with a particular focus on Scotland. They wanted to establish which varieties of flax were most suitable for their soils and climate, so they teamed up with James Hutton Institute, Edinburgh College of Art, Fantasy Fibre Mill, and Heriot Watt University to conduct on-farm research through an Innovative Farmers field lab.

Working with Soil Association Senior Farming Manager Colleen McCulloch, they established three trial sites across central Scotland, covering a range of soil types, altitudes, and enterprise types to assess the performance of three flax varieties. Support from researchers at the James Hutton Institute enabled robust and comprehensive data collection on height and yield.

One of the growers, Rosie Bristow, also lead research into the development of open-source flax-fibre processing machinery, through the project Fantasy Fibre Mill. This enabled testing and innovation across the regenerative textile supply chain.

Image

A yellow combine harvester, harvesting a cereal crop.

The Trial

Three new Dutch varieties of fibre flax (Linum usitatissimum) – Avian, Delta and Tango – were trialled at three Scottish sites to compare their straw height (cm) and yield (t/ha). Each site grew three replicates of each variety in 10m² strips, sown in rows (8 rows per metre) either by hand or with a Jang seeder.
The crop was harvested before it was fully ripe to obtain the best fibre quality, at which point crop density, height, and weight were measured.
The retted straw was then sent to Fantasy Fibre Mill for processing into yarn, and the fibre quality and strength of both the retted straw and finished yarn will be tested by Heriot Watt University.

The Results

When compared by variety, both the average height (cm) and average weight (t/ha) were similar for the Avian and Delta varieties, and lower for Tango. However, variation between sites was high, particularly for yield (weight).
Weed pressure will account for some of this variation; Site 1 was weed-free and recorded consistently taller crop heights, and most of the biggest weights.
Harvesting was done by hand with teams of volunteers due to lack of access to specialist machinery – fibre flax needs to be pulled rather than cut. This worked well on a small scale, but harvesting on a commercial scale would require specialist equipment.

Farmer Insights

“The trial demonstrates that modern fibre flax varieties can grow well in Scotland, and we know there is growing appetite among farmers, crofters and growers to produce flax as a fibre crop. The next step is to scale up the processing capacity to allow flax to be grown on a bigger scale and harvested mechanically.” - Rosie Bristow, Flax grower and co-founder of Fantasy Fibre Mill