During the 16th Century, in Great Britain, Henry VIII encouraged farmers to plant the crop extensively to provide materials for the British Naval fleet. It took a steady supply of hemp for the construction of battleships and their components. Other items such as maps and Bibles were also made with hemp paper.
During the 17th century, farmers in America were encouraged to grow hemp. The United States census of 1850 states that there were a total of 8,327 hemp plantations, with each being a minimum of 2,000 acres. For years, farmers harvested hemp by hand. Finally a machine was built that would take care of the entire harvesting process and by 1920 the hemp crop was entirely harvested by machinery.
As time went on, competitors started viewing hemp as a threat. As a result a smear campaign against hemp was started, associating hemp with marijuana. To follow, propaganda films were released to assure hemp’s demise. When Congress passed the Marijuana Tax Act in 1937, the decline of hemp effectively began. The tax and licensing regulations of the act made hemp cultivation nearly impossible for American farmers.
However, during World War II, the Japanese attack on Pearl Harbor halted the importation of Manila hemp from the Philippines. Although American farmers were still prohibited by law from growing hemp, this situation did cause the USDA to reconsider their agenda. They created a call to action with the release of Hemp for Victory, encouraging farmers to grow hemp for the war effort. War Hemp Industries was created by the government to subsidize hemp cultivation. Over a million acres were grown across the Midwest as part of the program. As you could already guess, once the war was over the processing plants were shut down and the industry disappeared again.
From 1937 until the late 1960s the United States government recognized that Industrial Hemp and marijuana were two distinct varieties of the cannabis plant. After the Controlled Substances Act was passed in 1970, hemp was no longer recognized as being distinct from marijuana.