Known as feannagan in Gaelic, but common in the Hebrides, Highlands and western Ireland, they were formed by digging parallel ditches and piling the soil towards the centre. The ditches helped to drain what might otherwise be cold land and, by drying it, encourage it to warm in the spring sunshine. The practice also served to deepen the soil for planting. The beds were then fertilized with manure from cows and seaweed from the beach.
Potatoes were a crop which suited the climate and this form of cultivation. Typically, potatoes were planted in May, with the first ready in 100 days, though the main crop would take 130. One acre of good cultivation was sufficient to feed a family of six for a year. However, over-dependence on the potato led to the catastrophic famine that followed the arrival of blight in Scotland in 1846. Some 1.7 million people left Scotland between 1846 and 1852.