Kelp Crofting

Kelp Crofting

Three hundred years on from the collapse of the island kelp industry, marine scientist, Dr Kyla Orr, and her two colleagues, Alex Glasgow and Martin Welch, are bringing KelpCrofting back to the west coast with a proposal for a 11.5 hectare kelp farm in the waters south of Pabay, Isle of Skye.

(Photos courtesy of KelpCrofting)


Kelp formed the basis of a booming industry in the coastal Highlands and Islands in the 18th and 19th century. From Mull to Orkney, kelp was harvested, dried and burned in kelp kilns to form an alkali substance (kelp ash) that was used to bleach linen and also in the manufacture of glass and soap.

The rise in the demand for chemicals, coupled with the loss of competitive imports due to the Napoleonic wars, meant that the Scottish production of kelp ash became very lucrative indeed. At its peak, kelp ash production employed around 10,000 families in the west of Scotland. The population of South Uist, for example, increased by more than 200% between 1755 and 1831 with kelp production taking precedence over cattle, horses and even fishing as the main trade of the islands.

Unsurprisingly, it was the land-owning gentry who profited from the hard labours of their crofting tenants. Moreover, seaweed had previously been used to fertilise the islanders’ crops which now suffered due to landlord and industry demands for kelp.

The bubble burst after the Napoleonic wars ended and high duties on imported chemicals were dropped. The backlash of having been dependent on a single inflated commodity was dire. Severe poverty followed adding to the island clearances as people became economic migrants.

Kelp Crofting Today

In bringing KelpCrofting back to Scotland, Kyla and her team hope to create a sustainable, affordable community model that can be replicated around the coast of Scotland stimulating coastal economies and highlighting the many benefits of this versatile crop.

Having done her PhD on the impacts of wild harvesting kelp, Kyla knew that harvesting it from the wild was not an option. Kelp forms the base of coastal food webs providing important ecosystem services to a myriad of marine life. When growing on rocks, kelp provides habitat for invertebrates, fish, and the seabirds that dive down for food. Rotting on the beaches, kelp supports invertebrates and migratory birds.

Environmentally, kelp cleans the ocean as it grows by absorbing damaging excesses of nutrients from fish farms and agricultural runoff.

Kelp is also an important carbon sink. Considered a tree, rather than a plant, kelp performs the same functions as trees but in a different environment. Kelp absorbs dissolved carbon dioxide into its biomass and continues to fix carbon while it grows. In this way, kelp helps to mitigate climate change.

For all of these reasons, the best option is to grow kelp from seed and to leave the wild population alone.

Loch Linnhe sugar kelp |
(Photo: Keith Hiscock)

A Replicable and Affordable Model

The KelpCrofting team has cut costs by culturing the kelp seed themselves in a lab on one of their crofts using recycled fish tanks bought on ebay! At six weeks, the kelp will be transferred from the hatchery to lines installed on the seabed.

Scottish legislation regarding seaweed farming is strict. The chosen seabed must be carefully surveyed to make sure there are no sensitive or endangered species present. Being well connected to the local diving community, KelpCrofting were able to secure surveys at a reasonable cost.

Once the site is chosen and approved, tight ropes are anchored to the seabed with gaps about eight metres apart and floats at the surface. The ropes must be tight and checked regularly as loose ropes are a hazard to marine mammals such as dolphins and wales. The team were able to procure recycled anchors from the fishing industry to hold the ropes to the seabed.

Kelp takes 9 months to be ready for harvest. The harvest will take place over a 4 to 6 week period around the end of May and June. Harvesting at this time in the year, before other marine life that has migrated into the farm begin to really cover the fronds, is a measure to protect these other species. The kelp is harvested by hand. As it comes over the boat, the kelp is washed down with seawater which causes any attached species to fall back into the sea..

For markets that require the kelp to be dried, the team has polytunnels on one of their crofts with room to do this.


Unlike its historical production, the destination of KelpCrofting’s harvest will not be kelp ash, rather a range of innovative, sustainable and healthy markets.

  • Biodegradable Packaging

    For the first two years, KelpCrofting will provide seaweed in wet weight to an innovative company, Oceanium, who, amongst other things, are making biodegradable, home-compostable packaging as a replacement for plastics. The biomass KelpCrofting provides will permit Oceanium to test the technology and process with a goal of getting “proof of concept”.

    Thereafter, KelpCrofting will look to partner with local health practitioners, breweries, and possibly other food outlets as well as the fertiliser and cosmetic industries.
  • Fertiliser

    This is an exciting use of kelp as it provides a sustainable, organic alternative to damaging artificial fertilisers and farmyard manure. The islanders used to drag kelp up from the beach and put it directly onto their crops (something Kyla does today on her croft!). Currently, in the western isles, beach class kelp is piled up on the beaches and left to rot over winter where the rain washes the salts out. Then, it is put in the crop-sprayer and sprayed all over the crops. The RSPB have done studies to show that this natural alternative is much better for birdlife than artificial fertilisers.
  • Food, Health and Beauty

    From fresh kelp noodles to seaweed pesto the demand for this nutrient-rich food is rising in the plant-based food sector. Kelp contains the highest natural concentration of calcium in any food – ten times higher than milk. It is also a rich source of vitamins, proteins, fibre, and nutrients, most notably iodine, potassium, magnesium, iron and zinc.

    As a supplement, kelp can help to maintain healthy thyroid function; prevent the growth of certain cancers; improve bone density; and aid in the production of red blood cells

    Alginate – the fibre found in kelp – has been found to reduce fat absorption in the gut and therefore assist with weight-loss.

    Kelp is widely used in the beauty industry for, amongst other things, enriching the skin and promoting hair growth.
  • Beer & Spirits

    In days gone by, coastal breweries made beer from malted barley that had grown in fields fertilised by seaweed. Today, several Scottish breweries are recreating that distinct flavour by adding fresh seaweed into their mash.

(Photo: Isle of Harris Gin)

Guidance and Support

In North America, kelp farming is government subsidised and well supported by universities. As a result, many US fisherman have diversified to kelp farming. There are open-sourced, “how to” manuals available in the US which Kyla and the team found to be very helpful. They recommend Ocean Approved’s Kelp Farming Manual as a comprehensive guide for anyone interested in kelp farming.

Although setting up a kelp farm can be costly, KelpCrofting have found ways to cut costs. They hope to see a return from their investment in around two years. Their vision is for a network of small to medium kelp farms around the cost of Scotland. This could help to boost coastal economies and create employment.

The KelpCrofting team are willing to share their knowledge and experience with other would-be kelp farmers. So … get in touch! or visit their website for more information:

Cover photo: Young sugar kelp | Ocean Approved farm, Maine (Photo: Brittney)

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