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Forestry and fibre

Growing flax for regenerative textiles

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The research

This field lab involves growers who are part of an emerging network aiming to re-establish a regenerative textile (particularly linen) supply chain in the UK, with a particular focus in Scotland.

The trial’s main objectives are to ascertain how well flax grows in a range of soil types, measured by crop establishment and yield; and to compare the performance of 3 varieties in a range of soil types.

The secondary objectives are to explore factors which may influence the retting process (e.g. time retted, number of turnings, weather); and to compare the fibre quality of 3 varieties.

The benefits

  • 80% of the world’s flax crop is grown in Belgium, France, and the Netherlands
  • There is little contemporary research available on growing modern varieties in UK soil types and climates.
  • This trial is the first small step in exploring a resurgence in flax production and processing in Scotland.
  • If successful, it is hoped that it will lead to further trials on a larger scale, with a longer-term aim is of making a case for industry investment in specialist harvest and processing equipment. 

Trial design

There will be three main trial sites.  Each site will grow 3 replicates of each variety (Avian, Delta, Tango) on 10sqm plots, totalling 9 plots per site. Plots will be randomised in three reps. Seed will be sown in rows 125mm apart at a rate of ~10g/sqm.

None of these varieties are commercially available in the UK yet.

Other community growers will also be encouraged to take part in a wider, support trial. 

The field lab will follow the production process from seed to harvested crop; measuring establishment & yield and comparing these across varieties and sites.

The seeds for the trial are being provided by Elsoms Seeds.


Latest updates

The Scottish flax fibre field lab has learned a lot this year, testing three fibre varieties to see which works best in Scottish soils and climate. Watch the post-harvest video here.

The flax crop was harvested in August (see previous update for details), and has now been retted, dried, and transported to project partners at Edinburgh College of Art Textiles Department and Fantasy Fibre Mill for extracting the fibre, spinning, weaving and experimenting over the winter months. Some will also stay at one of the trial sites, Lauriston Farm, for on-site processing workshops. 


Jossie collecting retted flax for drying at Lauriston Farm
Jossie collecting retted flax for drying at Lauriston Farm

What is retting?

Retting is the process by which bacteria and water break down the woody stem (lignins and pectins) of the plant by laying it out in the field and turned for several weeks, and is a bit of a fine art. We are confident that most of the crop looks well retted but, with the changeable and often wet weather in September, it is quite possible that some of the flax has been over-retted. When this is the case, the over-retted bits will be brittle, and break into short fibres during processing rather than staying long and flexible. These short fibres can still be utilised in other ways (e.g. as animal bedding), but are not suitable for textile production. The fibre quality will become apparent during the processing (and be tested by project partners Heriot Watt University), and we will be able to refine our processes for next year. 


Weighing the dried, retted flax
Weighing the dried, retted flax

Crop yield 

A range of yields between 8–12t/ha was recorded across varieties and sites which, by all accounts, is pretty good; and one variety consistently measured shorter in height at all three sites. The harvest data is awaiting statistical analysis, which will show whether the differences in height and yield between varieties are significant.  

Niki Taylor of ECA Textiles Dept collecting some of the retted flax from Lauriston Farm
Niki Taylor of ECA Textiles Dept collecting some of the retted flax from Lauriston Farm

Next steps 

Plans are also underway to expand the field lab in 2024 by trialling the same three varieties – Avian, Delta and Tango – at more sites; refining the parameters based on what we learned this year and making the initial results more robust. Any reliable information we can share with the wider farming community on the performance of these new varieties, will be useful in supporting potential growers as well as the emerging flax and linen processing and supply chain. 

View the time lapse harvest video here: Time lapse video of harvest

How to harvest flax in Scotland

The flax has now been hand harvested on the three trial farms and took slightly longer than the recommended 100 days to mature. It is possible that drought in the spring/early summer and cooler temperatures in July may have affected growth and ripening.

Flax at Balruddery pre-harvest

The crop is ready to pull around 40 days after flowering, when the seed pods have changed from pale to brown and the stem has started to yellow. At this stage, the seed heads are not yet ripe but the flexible fibre in the stem is at its strongest for being processed into textiles. If over-ripe, the inner fibres break easily and become more difficult to process.


Harvested flax at Balruddery

Plants are pulled by hand to ensure maximum fibre length, as the fibre extends down into the root. It is then laid out on the ground with roots at one end and seed pods at the other, in a process known as retting (old Scots word for rotting) – where soil microbes and moisture in the damp ground break down the lignins and pectins in the woody stem, allowing the flexible fibres to be extracted for processing.

Bundling and labelling flax at Balruddery

After 10 to 20 days the crop is turned to allow the top layer to become damp and ret. The whole process is weather dependent and can take from two weeks to two months depending on conditions. When the crop is fully retted it needs to be dried and stored, ready to be processed and spun into yarn for weaving.


What was measured?

The main factors assessed were yield, crop height (which informs the fibre length), crop density (number of plants per plot) and crop weight (thicker stems might imply better quality fibre). A good crop would have tall, thick stems growing densely together.

We also wanted to know what factors may influence germination and growth (and whether this has a bearing to final yield), so recorded soil type, measured soil health and compared weed pressure.

Soil testing at the trial site

Observations were also made of differing root structure – ideally as little soil as possible will come up with the roots.

Some initial observations from the harvest

Of the three varieties, one appears to have performed less well than the other two, growing consistently shorter and less dense across all three sites

  • Weed pressures had a noticeable effect on crop yield
  • In plots with heavy weed pressure, crop density and height were lower than weed-free plots
  • Plots which previously had compost added produced taller and thicker plants
  • Further patterns may emerge once the data is analysed.

Next steps in this field lab

  • Retting and drying the crops for processing over the winter by Fantasy Fibre Mill and ECA textiles team/students
  • Lab testing by Heriot Watt University
  • Analysing data for results and recommendations
  • Recruiting growers and planning for 2024
  • Wider flax-growing/agronomy/industry/history research over winter
Balruddery processed flax

Aspirations for 2024

  • Recruit more farm sites into a scaled-up trial
  • Continue the community flax network and knowledge exchange on growing and processing flax into fibre
  • Continue to collaborate to support the development of a Scottish processing and supply network
Shirley McLauchlan demonstrating processing retted flax

Aspirations beyond 2024

This Innovative Farmers field lab is the first small step in a process that project participants and collaborators hope will be the start of the development and re-establishment of a thriving sustainable textile economy in Scotland (and the UK). There is a growing network of actors contributing to this work (e.g. the newly-established Fibreshed Scotland, Fantasy Fibre Mill, farmers who are interested in growing flax on a commercial scale, Journeys in Design/Flax Futures); and we hope that by working together we can develop a sustainable Scottish textile industry which empowers everyone in the processing and supply network.

If you want to get involved in the future – contact info@innovativefarmers.org to find out the latest.

Who is involved in the field lab?

The initial core group of three farmers, researchers from James Hutton Institute and Edinburgh College of Art has grown throughout the project and now also includes 30 community growers and a growing network of collaborators including a flax to yarn processing mill start-up – Fantasy Fibre Mill, spinners, weavers, dyers, educators, crafters and textile researchers.

The flax is now in the ground: three varieties across the three trial sites. There are also 30 community plots across Scotland taking part in the trials. The next stage will be in July / August when the flax will flower and then it will be harvest time.

Trial plot being sown - photo from Lauriston Farm

Seeds sown

May 2023


August 2023

Retting complete

September 2023

Crop collected

October 2023

Crop processed into yarn

December 2023

Linen products made

March 2024

Group Coordinator

A portrait of Colleen McCulloch.
Colleen McCulloch

Colleen McCulloch


Colleen McCulloch is an independent facilitator, consultant and project manager, specialising in agroecological food & farming systems. Formerly Soil Association Scotland’s senior farming programmes manager, she has spent the last 10 years building, supporting and mobilising farmer-led innovation groups and networks across Scotland and the UK. This has involved many inspiring projects, including leadership of Scotland’s Rural Innovation Support Service - a national collaboration which ‘connected farmers and supply chain actors to develop innovative projects, that delivered sustainable solutions to real world challenges’. Colleen has a mixed background in organic farming, research and ecology; and combines these to support the transition towards more organic and agroecological food production.


A portrait of James Hutton Institute.
James Hutton Institute