Weed control is by cultivation or low rates of paraquat. Climate is very important because sweetpotato is a tropical crop. High temperatures are required to achieve good yields, while cool, wet conditions prior to harvest may cause rotting. Harvesting is performed using a modified potato digger. Care must be taken not to damage roots with moving parts or by dropping them from a height.
High humidity helps to reduce shrinkage caused by water loss.
Access to planting stock Limited plants of these cultivars are available for research purposes. If commercial interest is expressed by individuals or groups the plant numbers may be bulked up to match the requirements. Current cultivars Owairaka Red is the traditional cultivar with its red skin and cream flesh. In the 1850s an American whaling ship introduced a sweetpotato variety that was named Waina by the Maori. Owairaka Red's strengths are its traditional image, high sprout production, acceptable yield and early maturity.