Babitha Jampala

Industrial hemp (Cannabis sativa L.) is a new crop for Louisiana. In 2019, the Louisiana industrial hemp plan was approved by the U.S. Department of Agriculture, and the Louisiana Department of Agriculture and Forestry (LDAF) started accepting applications for produce, transport and processing in December 2019. Many other states like New York, Colorado, Pennsylvania, Wisconsin and Kentucky had started hemp pilot projects with the help of universities and extension agencies in 2014. As these states started introducing hemp, the cultivars from Europe were introduced as conditions in the northern region of the U.S. are similar to those in Europe. There is no information on any of these cultivars’ suitability to the hot and humid conditions of the South.

At the LSU AgCenter, researchers evaluated some of the grain and fiber lines of industrial hemp at LSU AgCenter research stations in the summer of 2022. Sixteen cultivars of grain and fiber hemp were planted at Red River Research station in Bossier City and Macon Ridge Research Station in Winnsboro. These locations represent different soil types and climatic conditions. The field experiment at both the locations was laid out as a randomized complete block design with four replications. Table 1, which can be viewed at LSUAgCenter.com/AgMagFall2023, shows all the cultivars along with lab germination rates, which were evaluated in small plots of 5 feet by 20 feet each, and their seed sources. The seeding rate was adjusted based on the germination rate calculated in the laboratory conditions.

Plant stand data was collected from both locations. Figure 1, which also is available on the magazine website, shows the plant stand percentages for the hemp cultivars tested at Red River Research Station. Among the 16 cultivars, YuMa and NWG 2730 had the best plant stands. Figure 2, which also is available on the magazine website, displays the plant stand percentages for the same cultivars grown at Macon Ridge Research Station in summer 2022. YuMa and NWG 2730 had the highest plant stands, and Felina 32 and Bialobrzeskie have the lowest plant stand percentages.

Although the plant stands for some cultivars were good, extreme drought and weed pressure — especially pig weed — resulted in the failure of the crop at Red River Research Station. Testing the suitability of the hemp crop in the fall season for Louisiana will be useful. In Macon Ridge, the cultivars were performing better than Red River, but the heavy rainfall in the month of August in 2022 led to difficulty in harvesting the hemp crop.

Many cultivars had significantly lower germination percentages than those reported by the lab. The reason for lower germination rates in the field are high soil temperatures and drought during the planting season. Many of these cultivars are also being evaluated at the AgCenter Doyle Chambers Central Research Station in 2023 and had poor germination as observed in summer of 2022. A gibberellic acid (GA) treatment for enhancing seed germination percentages also was tested. Gibberellic acid is a naturally occurring hormone that can influence seed germination. According to a 2022 study by researchers at the Institute of Resource Plants at Yunnan University in Kunming, China, hemp seed pre-soaked in gibberellic acid at certain concentrations promoted seed germination under drought stress. But when used in our conditions the germination rate was better after 400 ppm of GA treatment for 24 hours, but the germinated seedlings were weak and tall. Another planting of the same cultivars was done in fall on Oct. 2, 2023, at the AgCenter Doyle Chambers Central Research Station. Germination rates of all the cultivars were significantly higher than the summer planting.

In conclusion, for two years in a row, poor germination of the cultivars was observed at all the tested locations with summer plantings. Planting hemp in the fall as a fall crop starting in October as the temperatures cools down seems to be a better option. More studies are required to establish suitable planting times for hemp in our state.

Babitha Jampala is an assistant professor in the LSU AgCenter School of Plant, Environmental and Soil Science.

This article appears in the fall 2023 edition of Louisiana Agriculture magazine.

Hemp grows in a research plot at the AgCenter Botanic Gardens at Burden in Baton Rouge. Photo by Randy LaBauve

Hemp grown for research purposes is identified with a sign to meet Louisiana Department of Agriculture and Forestry guidelines. Photo by Randy LaBauve