Hemp Variety Trials

Organic Hemp Variety Trials


HempIndustrial hemp (Cannabis sativa) is a fiber, oil and seed crop with a 5,000 year history of cultivation. It was first planted in Kentucky in 1775, and Kentucky's Bluegrass region was the center of the US hemp industry through much of the 1800s.

Kentucky's hemp industry declined rapidly in the late 1800s, recovered briefly during the two world wars, and virtually disappeared by the late 1940s. Contributing factors to the decline included competition from cheaper imported fibers like jute, manila, and sisal; falling costs of domestic cotton production; and increased regulation.

Hemp production was restricted by the federal Marihuana Tax Act  of 1937, which required hemp growers, importers, and processors to be registered and taxed. The Controlled Substance Act of 1970 made hemp a controlled substance under Federal Law, with production regulated by the US Drug Enforcement Administration (DEA).

Kentucky is one of several states to have legalized the cultivation and research of industrial hemp. The 2014 Farm Bill allows State Agriculture Departments, colleges and universities to grow hemp for academic or agricultural research purposes in states such as Kentucky, where industrial hemp farming is legal under state law.

Although few Kentucky growers have experience with industrial hemp, it is widely grown in more than 30 other countries, including Canada, which supplies many of the hemp products sold in the USA. Canadian hemp growers have been able to obtain premium prices for certified organic seed: In 2003-04, conventional hemp seed sold for 50-60 cents per pound, while organic seed fetched 85 cents per pound. By 2012, conventional hemp seed prices had increased to 70-80 cents per pound, while organic sold for $1.10-$1.20 per pound.

Hemp is reputed to out-compete many weeds, which could make it a valuable component of organic crop rotations in Kentucky. A particular concern to Kentucky's organic growers is the perennial johnsongrass (Sorghum halepense), which spreads rapidly by seed and rhizome, diminishing yields of many crops. Hemp's tall canopy, deep roots, and dense, thick growth habit may enable it to smother johnsongrass when used as a component of organic rotations. According to The Western Agriculturist and Practical Farmer's Guide (1830), "Nothing cleanses and prepares the earth better for other crops (especially for small grains or grasses) than hemp. It eradicates all weeds and when it is taken off, leave the field not only clean, but smooth and even."

Kentucky State University is conducting hemp variety trials on certified organic land in 2014, to determine yield and competitiveness of hemp varieties that show promise for certified organic production on small farms in Kentucky.


    1. Compare yield and quality parameters of four hemp varieties grown on certified organic land.
    2. Evaluate hemp's ability to compete with johnsongrass (Sorghum halepense).


Variety Trial. The organic hemp variety trial will be conducted in 4' x 16' plots containing six rows each (8" row spacing). Sixteen plots will be divided into four randomized complete blocks, each containing four hemp varieties: (1) Finola FIN314; (2) Fedora cross; (3) Kompolti; or (4) a Kentucky heritage variety. Seed will be drilled into prepared soil in April. Aboveground biomass will be collected from subplots 50, 75, 100, and 125 days after planting, then dried to measure dry matter production. Seed will be collected and weighed at final harvest, and oil will be extracted and weighed.

Weed Competition Trial. In April, 2014, an area infested with johnsongrass (S. halepense) will be cultivated and divided into twenty 4'-wide strips, arranged in a randomized complete block design. Each block will be seeded to one of four crops thought to have potential for johnsongrass mitigation in organic crop rotations: (1) buckwheat (Fagopyrum esculentum); (2) kenaf (Hibiscus cannabinus); (3) cowpea (Vigna unguiculata) and hemp (C. sativa). A fifth strip in each block will be left uncultivated, and mowed periodically to prevent johnsongrass seed set. Aboveground biomass will be collected from subplots 50, 75, 100, and 125 days after planting. Biomass will be divided into cover crop, johnsongrass, and other weed components. Each component will be dried to measure dry matter production. The demonstration will be repeated in 2015, with half of each plot planted to the same cover crop as in 2014, and the other half planted to corn.


Thanks to:

  • Mike Lewis for providing hemp seed.
  • Mac Stone, Kirk Pomper, and Teferi Tsegaye for administrative support.
  • Kentucky Department of Agriculture, for arranging university hemp trials.

Updated 03/31/14

College of Agriculture, Food Science and Sustainable Systems