$452 million: That's the value of retail products containing imported hemp that were sold in the United States in 2011. While a cousin of marijuana, the plant can't get you high. Instead, it can be used to make clothes, horse bedding, auto parts, soap and even concrete. But thanks to it being classified like all cannabis plants as a Schedule I substance - the same as heroin - the U.S. hemp crop is precisely zero. If you want to grow hemp and avoid a jail sentence, you need a permit from the Drug Enforcement Administration.