SNIPPET: Potatoes (Solanum tuberosum) originated in the South American Andes. Wild potatoes were brought into cultivation some 2,000 years before the Spanish conquest. They reached Europe in the late 16th century and were cultivated in English gardens a few years later. Their arrival in Ireland is obscure ... There is no certain evidence about the date or means of arrival, although tradition gives Sir Walter RALEIGH the credit. The earliest documentary reference to potato cultivation in Ireland is in a lease dated 1606 granting Scottish immigrants land in Co. Down. Potatoes were initially grown as a garden crop. In the 1640s and 1650s they were common in the gardens of the provinces of Munster and Leinster. The most plausible explanation for transition from gardens to fields is that potatoes were an excellent clearing crop on newly tilled land and valuable as a rotational crop to restore the fertility of land used for cereals. As the demand for Irish cereals increased, potatoes entered cultivation regimes. The process accelerated from the mid-18th century under the stimulus of rising cereal prices. Potatoes in Ireland served similar functions to those of turnips in England, but they were better suited to Ireland's cool climate and wet soils. To cultivate, ridges, called 'lazy beds', were dug in which the sprouting tubers were placed. Several varieties were grown (black, cup and apple varieties) and were highly prized. The poor cultivated the high-yielding though watery 'lumper.' By the early 19th century over two million acres were under potatoes, yielding from 6-8 tons per acre ... Until cultivated as field crops on a large scale, potatoes were never more than a dietary supplement. However, by the early 19th century they were the staple food, assuring the poor of a highly nutritious diet. The most common method of cooking was boiling. Consumption was 10-15 pounds daily ... Between 1845 and 1849 the potato crop was ruined three times by 'Phytophthora infestans' - potato blight. Since over three million people were totally dependent upon potatoes for food, famine was inevitable ... E. Margaret Crawford, Senior Research Fellow, Centre for Social Research, Queen's University, Belfast.