I have read this article: Cannabis found in Viking grave
The article are about the Oseberg boat Grave in Tørnsberg, Norway. The article seems to be quite accurate, except for the wording. It is true that Cannabis was found in a leather purse found with the elder lady (the word sack seems to imply something larger). What the article doesn’t tell are that the cannabis are in the form of seeds and that seem to be forgotten in the article.
to be no doubt that cannabis was farmed in Norway during the Vikinge Age. Beside
the purse with the seeds found in The Oseberg Mound and other places, we also
have found hemp pollen in a bog in Vest-Agder in Norway. Hemp pollen doesn’t move
very long, but a bog would be a bad place to grow hemp. This seem to indicate that
the hemp was placed there to loosen the fibers so that it would be possible to
make rope or clothes from the fibers. (From Norwegian Vikings grew hemp)
I’m not aware of which kind of hemp was found in Viking-age Norway, not all strains have high percentage of THC which gives it the psychoactive effects and as said its likely that the hemp pollen found in Vest-Agder was grown to make fibers, but that doesn’t mean, that they didn’t also use hemp for its psychoactive effects. We just don’t know.