<P> After the collapse of the Soviet Union, the commercial cultivation of hemp declined sharply . However, it is estimated that at least 2.5 million acres of hemp grows wild in the Russian Far East and Black Sea regions . </P> <P> In the United Kingdom, cultivation licences are issued by the Home Office under the Misuse of Drugs Act 1971 . When grown for non-drug purposes, hemp is referred to as industrial hemp, and a common product is fibre for use in a wide variety of products, as well as the seed for nutritional aspects and for the oil . Feral hemp or ditch weed is usually a naturalized fibre or oilseed strain of Cannabis that has escaped from cultivation and is self - seeding . </P> <P> Hemp was made illegal to grow without a permit in the U.S. under the Controlled Substances Act passed in 1970 because of its relation to marijuana, and any imported hemp products must meet a zero tolerance level . Some states have made the cultivation of industrial hemp legal, but farmers in many states have not yet begun to grow it because of resistance from the federal Drug Enforcement Administration, making "large - scale hemp growing" in the United States "not viable" as late as 2013 . In 2013, after the legalization of cannabis in the state, several farmers in Colorado planted and harvested several acres of hemp, bringing in the first hemp crop in the United States in over half a century . Colorado, Vermont, California, and North Dakota have passed laws enabling hemp licensure . All four states are waiting for permission to grow hemp from the DEA . Currently, Oregon has licensed industrial hemp as of August 2009 . Congress included a provision in the Agricultural Act of 2014 that allowed colleges and state agencies to grow and conduct research on hemp in states where it is legal . Hemp production in Kentucky, formerly the United States' leading producer, resumed in 2014 . </P> <P> As of 2015 the hemp industry estimated that annual sales of hemp products were around US $580 million annually; hemp seeds have been the major force driving this growth . </P>

When did hemp become illegal in the us