The Kelp Boom: Burnt Seaweed and the Fate of the Highlands

Each major claim carries one of three labels. established means supported by primary records, official bodies or several independent reliable sources. shared means the core fact is sound but sources disagree on details, dates or interpretation. traditional means widely repeated but not traceable to a primary or independent source.

Production and price figures vary between estates and sources, so this card avoids exact tonnages and prices. The relationship between kelp and later clearances is debated, and the card presents it as such.

Burning seaweed

established Kelp-making began in Scotland in Orkney in the early eighteenth century and spread through the Hebrides and along the west coast. Seaweed was cut from rocks at low tide or gathered after storms, dried on the shore and burned slowly in shallow, stone-lined pits for many hours. The molten residue cooled into hard, dark lumps of kelp, which were broken up and shipped to glassworks and soap-makers in Glasgow, Liverpool, Newcastle and elsewhere.

The boom

established Industrial Britain needed alkali for glass and soap. The best source was barilla, made from plants burned in Spain, but during the French Revolutionary and Napoleonic Wars imports were disrupted and taxed. Kelp prices rose dramatically, and landowners in the Hebrides, where seaweed was abundant, earned large incomes. On some estates kelp brought in more than rents.

Crofts for kelpers

shared Kelping needed many hands for a few months each summer. Many landlords, notably in the Outer Hebrides, divided land into small coastal crofts, too small to support a family by farming alone, so that tenants would need to work the kelp. Landlords set the wages and kept most of the profits. Some also opposed emigration in this period because they wanted to keep their labour force. Historians see this reorganisation as one origin of the crofting system.

The collapse

established After 1815 the price of kelp fell. In the early 1820s the government reduced duties on imported barilla and on salt, making salt-based chemical alkali cheaper, and the Leblanc process for making soda from salt was soon adopted on a large scale. Within a few years kelp lost most of its value.

Aftermath

shared The collapse left estates in debt and a large population crowded on small crofts with no cash income. Many landowners, now facing losses, turned to sheep farming and encouraged or forced emigration. When the potato blight struck in the 1840s, the result was famine and further clearances. Historians such as Eric Richards and T. M. Devine have shown the importance of kelp in this story, though they weigh it differently against other causes such as population growth and the economics of sheep.

Kelp and emigration

established Kelp turned landlords against emigration and then, after the collapse, in favour of it. The historian Marjory Harper, in Adventurers and Exiles (2003), notes that Highland proprietors, "particularly those on kelping estates", stayed solidly opposed to emigration until 1800, arguing that only a large tenantry could make their estates profitable. Through the Highland Society, the landlord lobby steered the Passenger Vessels Act of 1803 on to the statute book. Harper describes it as legislation "masquerading" as humanitarian whose real aim was to make emigration too expensive, prompted by inflated fears of how many the emigration agents would take. In Orkney, ministers of the 1790s complained that men leaving for the Hudson's Bay Company depleted the farming, fishing and kelping labour force.

shared After 1815 the same landlords reversed course and began encouraging, and sometimes paying for, emigration. In 1827 Duncan Shaw, factor of the Clanranald estates, warned that unless proprietors chose who went, "the most wealthy and industrious of our population will emigrate, and we will be left with the dregs". Having failed to get state funding, Maclean of Coll paid in 1826 for 300 of the 350 people on Rum to go to Cape Breton, then let the island to a single sheep farmer for nearly three times the old rent. Harper counts that episode as forced clearance rather than voluntary relocation. How far the kelp collapse, rather than population growth or sheep prices, drove these decisions remains debated.

After the boom

established Small-scale kelping continued through the nineteenth century for the extraction of iodine and other chemicals, and seaweed remains a resource for fertiliser, food and alginates today.

Kelp and the making of the crofting townships

shared The geographer Robert Dodgshon shows how kelp shaped the Highland landscape. During the Napoleonic Wars a sharp rise in kelp prices, and the labour that kelp-making demanded, gave landlords a direct interest in packing people into their coastal townships, while high sheep prices encouraged them to clear the inland grazings. Kelp, fishing and the potato together lowered the threshold of what counted as a viable croft, and some estates distinguished "full" crofts from "half-crofts" that depended on income from kelp or fishing.

established When kelp prices collapsed after 1815, along with cattle and grain prices, the townships built around it were plunged into crisis. Landlords who had encouraged crowded coastal communities now saw them as a burden, and many estates were sold to new owners from commerce and banking with fewer ties to their tenants. The island of Ulva shows the turn: an 1825 sale advertisement said its crofters made "a very handsome profit" from kelp, but by the late 1840s the new owner was clearing them for sheep.

• The naturalist John Walker won the Highland Society's top gold medal in 1788 for an essay on kelp. He proposed planting seaweed on rocks set along beaches, but admitted that Scottish kelp could survive only behind high duties on foreign alkali. The chemist Joseph Black declined to help, having already judged it inferior to Spanish barilla (Jonsson, 2013).
• An 1825 sale advertisement for Ulva boasted that its crofters made "a very handsome profit" from kelp; within about 25 years the new owner was clearing them for sheep.
• Kelp is both the name of the seaweed and the ash made from it.
• Kelp ash was used to make glass and soap.
• Prices peaked during the Napoleonic Wars.
• Some landlords created small crofts to keep kelp workers on the land.
• The collapse of kelp prices in the 1820s helped cause destitution and emigration.

• Disputed: How much kelp was made and what it sold for. Production and price figures vary between estates and sources, so exact tonnages and prices are uncertain.
• Myth: Kelp was the single cause of the Clearances. Historians such as Eric Richards and T. M. Devine show its importance, but weigh it differently against other causes such as population growth, the economics of sheep and the potato famine of the 1840s.
• Myth: The Passenger Vessels Act of 1803 was a humanitarian measure. Marjory Harper describes it as legislation "masquerading" as humanitarian, steered through by the landlord lobby to make emigration too expensive.