Researchers show sweet potatoes can grow in Finnish fields

A four-year University of Helsinki study has found that sweet potatoes can be grown in Finland, although the crop needs suitable varieties and growing methods to cope with the country’s cool climate and short season, Yle reports.

Researchers tested eight varieties at a field in Viikki, Helsinki, where this autumn’s harvest marks the end of the field trials. The results are promising, said doctoral researcher Anuruddi Halvitigala, who said further work is needed to identify varieties and cultivation practices suited to Finnish conditions.

Sweet potatoes need warmth and enough time to grow. At the Viikki field, they have been grown outdoors under plastic mulch, which helps warm the soil and retain moisture. The plants have also needed irrigation. Frost limits planting in spring, while the roots must be harvested soon after autumn night frosts damage the leaves.

White and Early Orange have performed best at the field from year to year. The study also tested varieties with white, yellow and purple flesh, as well as the familiar orange kind.

Sweet potato cultivation in Finland is currently very limited, and shop-bought supplies are imported, mainly from the United States and Egypt. Finland imported more than four million kilograms of fresh sweet potatoes last year, according to Customs. The researchers say growing the crop domestically could diversify Finnish agriculture and reduce the need for long-distance transport. The research will continue, including work to assess the sweet potatoes’ nutritional values.