The Rise and Fall of the Kelp Industry on the Isle of Mull

A William Daniel painting of kelp burning at Gribun, Isle of Mull

For much of the early 19th century, the Isle of Mull was shaped not only by crofting and cattle but by something far more surprising: seaweed. Long before the potato famine transformed life in the Hebrides, Mull’s coastline was the centre of a thriving kelp industry—an industry that promised prosperity, altered the island’s economy, and ultimately left communities more vulnerable than they had ever been.

This is the story of Mull’s kelp boom, the people who worked it, and the collapse that helped set the stage for the crises that followed.

What Was the Kelp Industry?

The “kelp industry” refers to the harvesting and burning of seaweed—specifically species like kelp and wrack—to create soda ash, a substance used in the production of glass, soap, bleach, and ceramics. In the late 18th and early 19th centuries, before chemical alternatives existed, coastal communities across Scotland became major producers of this valuable ash.

Mull, with its long, rugged coastline and sheltered bays, was in a prime position to benefit. Many crofting families supplemented their modest agricultural income with kelping, which became essential for paying rent and maintaining their tenancy.

A Booming Industry on Mull’s Shores

The kelp boom began during the Napoleonic Wars (1803–1815), when foreign soda imports were blocked and prices skyrocketed. On Mull, the industry expanded rapidly:

• Entire communities devoted summers to kelping.

• Landlords invested in new facilities and shoreline organisation.

• Women and children took part, making it a truly communal enterprise.

• Some estates relied on kelp revenue as their primary source of income.

At its peak, kelp ash could fetch over £20 per ton—an enormous sum for the time.

For many on Mull, kelp offered something rare: stability. It kept tenants on the land, allowed rents to be paid, and gave a measure of independence to communities that had few other economic options.

The Labour and Rhythm of Kelp Harvesting

Harvesting kelp on Mull was hard, dirty, physical work. Coastal families spent long tidal days:

1. Cutting seaweed from rocks with sickles

2. Stacking it to dry on shorelines

3. Burning it in stone-lined pits for hours

4. Breaking up the hardened ash blocks

5. Transporting them for sale by boat

Smoke hung along the coast through midsummer, and the smell of burning kelp was unmistakable. It was demanding labour, but it was also one of the few ways crofters could bridge the gap between what the land produced and what the landlord demanded.

Landlords and the Kelp Fortune

Many Mull estates—such as those on the Ross of Mull, Tobermory Bay, and Ulva—relied heavily on kelp revenues. During the boom, kelp wealth allowed landlords to avoid evictions, maintain estate infrastructure, and support growing populations. In some cases, it even delayed early phases of the Highland Clearances on Mull.

But this reliance came at a cost: when the kelp market collapsed, so did the financial foundation of many estates.

The Sudden Collapse

After the end of the Napoleonic Wars, European trade routes reopened, and cheap chemically produced soda ash flooded the market. Prices plummeted. By the 1830s, the once-thriving kelp industry had become almost worthless.

For Mull, the consequences were severe:

• Crofters lost a crucial source of income.

• Landlords were suddenly in financial crisis.

• Rents remained high even as earnings fell.

• Families were pushed into poverty or forced to migrate.

Some estates began to restructure, consolidating crofts into large sheep farms—a trend that would accelerate later during clearance periods. Others increased pressure on tenants or sought ways to downsize their populations.

The collapse of the kelp industry weakened Mull’s social and economic fabric at precisely the moment population was rising. When the potato blight reached Mull in the 1840s, the island was already on unstable ground.

Kelp’s Legacy on the Isle of Mull

Today, traces of the kelp industry still dot the coastline:

• Stone-lined burning pits - a good example is on Ulva, where there is a ruined kiln on the south shore

• Ruins of storage huts

• Abandoned coastal settlements

To the casual visitor, these remnants blend into the landscape—but to historians, they speak of an era when seaweed underpinned the island’s entire economy.

The kelp boom and bust reshaped Mull’s population, economy, and relationship with the land. It offered hope before turning to hardship, leaving communities more vulnerable to the disasters of the late 1840s.

Why the Kelp Industry Matters in Mull’s Famine Story

The collapse of kelp revenue didn’t cause the potato famine—but it multiplied its effects. Without kelp income, crofting families had little financial buffer. Landlords, struggling with debt, were less equipped to support tenants. Many who might have weathered a bad harvest in earlier years found themselves with no safety net at all.

Understanding the kelp industry is essential to understanding the fragility of life on Mull in the pre-famine era.

Coming Next in the Series

In the next article, we’ll explore how the potato blight reached Mull, how it spread across the island, and why the first year of failure proved so devastating.