There is a wide misconception that hemp is just another word for cannabis, or at the least there is no difference between the two words. However, that is wrong. Hemp and cannabis are used for totally different reasons, and hemp is not completely illegal in the governments eyes. In fact, 32 states have industrial legalization laws for hemp due to the Farm Bill passed in 2014.
Cannabis and hemp both stem from the same plant species Cannabis Sativa L, which was grown by George Washington at Mount Vernon. Years of breeding have caused two varieties within this plant species. Cannabis plants tend to be shorter, and wider than hemp plants. Farmers try to give the plant as much room to grow, because the more light, water, and air the plant gets the more buds it will produce. These buds will turn into the flowers which produces cannabis. Cannabis is the flower and the leaves of Cannabis Sativa L, which are the parts that produce THC. Cannabis is used primarily for medical and recreational purposes to relax, treat ailments, etc... through ingestion of some kind. It is the most widely known part of Cannabis Sativa L, and the focus of public policy attention throughout the country. However, due to its psychoactive effects, it is frowned upon by the federal government and placed as a Schedule I drug.
Hemp is the other variety of Cannabis Sativa L. There are distinct physical differences between the two. Hemp is raised by farmers to be tall and skinny. Farmers cultivating hemp focus more on the stalk and seeds, and ignore the rest. This is because hemp is made for the seeds and fiber to create industrial products like canvas, rope, etc... In fact the name "canvas" is derived from the dutch word for cannabis. Scientists are looking for ways to make a hemp-based plastic, which really shows the versatility of this plant. Currently 32 states have industrial legalization laws in place for the use of hemp, but it seems this is because hemp is associated with cannabis. Thereby, it is still considered illegal at the federal level still.
Hemp should have no restrictions as it is used for purposes completely different from its counterpart, and has many applicable industrial uses. In fact, hemp is not allowed over 0.3 percent THC or it gets classified as a cannabis plant. With this restriction I do not see a reason why hemp is not allowed to be cultivated freely.