ABSTRACT
During the 1900’s fiber hemp was commercially grown in Scandinavia at latitudes as far north as 65°N and 66°N. Hemp is sensitive to temperature and day length with a quantitative short-day requirement, though long days can be beneficial for fiber production in late varieties, provided that other growing conditions are optimal. The response of fiber hemp varieties to photo period and low temperatures at northern latitudes was studied in Finland in 2003 and 2004. The article also reports on risks and prerequisites of hemp growing at high latitudes showing that if a suitable variety is used, stem yields of more than 10 t ha−1 are possible. If a variety adapted to southern European climates should be grown, however, the short growing season and the frosts in the beginning and at the end of the summer can restrict the plant growth. The northern limit for hemp production in Europe is currently at 64 to 65°N.
The authors wish to thank Mr. Kauko Kyläsorri and Miss Johanna Andersson for their diligent field and laboratory work. This study is based on data collected during the project Hemp Sys (QLK5-CT-2002-01363) funded by European Union (EU). We kindly acknowledge the project organization and the EU.
Notes
de Meijer, E. 1994. Diversity in cannabis. Thesis, Wageningen, The Netherlands.
Nordstedt, O. 1920. Prima loca plantarum suecicarum. Första litteraturuppgift om de i Sverige funna vilda eller förvildade kärlväxterna. The first reference to wild and cultivation escapes of vascular plants in Sweden. Bilaga till Botaniska Notiser 1920: 1–95.
Pasila, A. 2004. The dry-line method in bast fibre production. Dissertation, University of Helsinki, Faculty of Agriculture and Forestry.
Sankari, H. 2000a. Towards bast fibre production in Finland: stem and fibre yields and mechanical fibre properties of selected fibre hemp and linseed genotypes. Dissertation, University of Helsinki, Faculty of Agriculture and Forestry.
Sauli, J.O. 1946. Tärkeimmät peltokasvijalosteemme. Our most important field crop cultivars. Eripainos Pellervon vihoista 2–11.
Sundberg, M., Westlin, H. 2005. Hampa som bränsleråvara. Förstudie. Hemp as a fuel. Preliminary study. JTI-rapport. Lantbruk & Industri 341.