World War II provided a new opportunity and the 1942 Japanese invasion of the Philippines cut the U.S. off from their major source of imported hemp. To meet the demand for war production, the U.S. and Canadian governments lifted the restrictions. Until the end of the war, farmers with special permits grew hemp to supply the war effort. To encourage farmers to grow hemp during this period, the United States Department of Agriculture released the film “Hemp for Victory”.
It stated, “In 1942, patriotic farmers at the government’s request planted 36,000 acres of seed hemp, an increase of several thousand per cent. The goal for 1943 is 50,000 acres of seed hemp.” This lead to over 400,000 acres of hemp planted throughout the Midwest and Southeast.
From <https://www.totalhemp.co.uk/history-of-hemp/>