In 1763, Jo Eom, a senior Joseon official, traveled to Japan as an envoy and brought back sweet potato seed stock upon his return. Cultivation began first in Dongnae, near Busan, and on Jeju Island, and from there the crop is understood to have gradually spread along the coastline, eventually reaching and taking root in Haenam. A crop that entered Korea from an external source, Japan, thus took considerable time working its way through various points along the southern coast before finally settling in Haenam's soil.
There are clear reasons why Haenam became an ideal region for growing sweet potatoes. The area's relatively mild winters make it well suited for storing the harvested crop, and its mineral-rich ochre soil combined with abundant sunlight produces sweet potatoes with high starch and sugar content. Since 2005, the Haenam County Agricultural Technology Center has been supplying virus-free, tissue-cultured sweet potato seedlings to local farmers. As of 2018, Haenam alone was producing 21,492 tons of sweet potatoes across 1,554 hectares of farmland. A single crop brought home by one envoy has, 260 years later, become the specialty product that most readily brings the very name "Haenam" to mind.