As sweet potato is a major cash crop in Central Luzon, the Philippines, demand for planting material is always high. Differences in the agro-climatic conditions in Central Luzon have resulted in different yet complementary growing seasons. Sweet potato is grown from May to July in the uplands of Bataan province, and from September to December in the vast lowlands of the Tarlac province. This means that the harvest time in Bataan happens at just about the time that farmers from Tarlac are in need of planting material. This has given rise to a flow of sweet potato planting materials across Central Luzon.
