Maybe you have heard of hemp in recent years, as momentum behind a movement to legalize the agricultural crop has grown with federal legislation and some states supporting it.

Even Kansas considered legalizing production of hemp in pilot research programs in early 2016. Hemp production in the U.S. faces big obstacles, though, including overcoming the stigma of its close relative marijuana and competing in an already competitive world market for hemp and hemp products.

Biologically, hemp and marijuana are variations of the same plant species, Cannabis sativa, but are considered to be separate and distinct subspecies. The major difference in the two plants is the concentration of tetrahydrocannabinol (THC) found in the plant.

Federal law now defines the difference between hemp and marijuana at 0.3 percent THC, with plants containing less than that amount classified as hemp and plants containing more than 0.3 percent THC classified as marijuana. Despite what sounds like an insignificant difference, most hemp is far below the limit and marijuana is much higher, containing 20 or even 30 percent THC.

Hemp got its bad reputation when federal legislation outlawed marijuana and failed to distinguish between the two plants.

Advocates for hemp claim the crop is useful for more than 25,000 products including fiber, paper, cosmetics, animal feed, biofuels, seed, oil and many more. From a simpler agricultural standpoint, the crop is grown for fiber or for seed (rarely for both), with the value of fiber being less than half that of seed and seed oil. China and Europe control the global hemp market, with Canada, Russia, Australia and about 30 countries worldwide growing hemp.

Besides the basic challenges of breaking into the market, little is known about how to grow and cultivate hemp for maximum production in relation to U.S. soils, weather, water, fertilizer, and pest control needs. Pilot programs in the 20 states that have passed legislation allowing research are working to assess these needs but have yet to provide conclusions.

Researchers are especially challenged with finding quality seed sources, as federal law still prohibits interstate movement and foreign-produced seed lacks guarantee of germination rates. They are also struggling with pest control, since there are no pesticides (especially for insects, diseases or weed control) labeled for use in hemp production in the U.S.

Hemp requires special harvesting and processing equipment, which producers will have to import until manufacturing develops. The processing chain will also take some time.

The Federal Farm Bill of 2013 gave authority to states to allow certain educational and government institutions to grow hemp for research or pilot programs. At least 20 states have passed legislation to allow these programs.

Hemp is native to central Asia and the Middle East. It was brought to the U.S. for cultivation by early colonists who were growing it for the British Empire.

Birds love hemp and are very effective at carrying the seeds, resulting in the stands of wild hemp that pop up across much of the Midwest.

— Jennifer Smith is a former horticulture extension agent for K-State Research and Extension and horticulturist for Lawrence Parks and Recreation. She is the host of “The Garden Show.”