The Potato, for many years the staple of the Irish peasant diet, contains a large quantity of starch, a small amount of protein, vitamins C, B1, and riboflavin and provides many of the daily essential nutrients. It is a member of the nightshade family which includes other "New World" crops like tomatoes, peppers and tobacco. The potato was first brought from the Americas to Europe in 1573 and introduced to Ireland about 1590. By 1780 it was the staple of the Irish diet. When the potato-crop failed in Ireland in 1845-1851 due to blight, 1 million people died from starvation and disease, 1 million emigrated and the population of the island fell by about 25%. This period is known as the Great Famine. In Irish it's call 'An Gorta Mór' meaning "the Great Hunger". The famine was a watershed in the history of Ireland. Its effects permanently changed the island's demographic, political and cultural landscape.
The traditional Irish method of planting the potato was in "lazy beds". Shallow trenches were dug at about three foot intervals. The sod and dirt were piled in between the trenches. The beds were enriched with manure, rotted straw, and/or sea weed. Whole potatoes were cut into pieces so that each piece contained an eye. These seed potatoes were usually put in the ground in May.
Reference: http://www.maggieblanck.com/Mayopages/Potato.html
Reference: http://en.wikipedia.org/wiki/Great_Famine_(Ireland)