Semester of Graduation

Summer 2025

Degree

Master of Science (MS)

Department

Plant, Environmental Management and Soil Science

Document Type

Thesis

Abstract

Industrial hemp (Cannabis sativa) production in Louisiana began in 2020 with 932 acres cultivated for fiber and cannabidiol (CBD) extraction. By 2024, production had declined to just 58.4 acres (Louisiana Department of Agriculture and Forestry, personal communication). During the 2020–2021 season, over 40% of field-grown hemp was lost due to tropical storms, insect pressure, and diseases associated with warm, wet conditions. To mitigate these challenges, hemp was planted and harvested between November and January, a cooler period with reduced environmental stress.

‘Sour Citron’, a day-neutral cultivar, was selected for its insensitivity to photoperiod, enabling flowering during shorter days. It was planted on three dates and harvested 60–70 days post-seeding to optimize yield while remaining compliant with Louisiana’s legal tetrahydrocannabinol (THC) threshold of 0.3%. All plants remained compliant; however, fresh biomass yields were modest, averaging 47.5 grams per plant. Dry weight averaged 17.83 grams, and flower yield was 5.4 grams per plant. Despite low yields, disease pressure was minimal, allowing full plant maturation.

These results suggest that while off-season production reduces biotic stress, yield limitations persist. Further research should evaluate additional day-neutral cultivars and explore increased planting densities to enhance per-acre productivity. Temperature optimization during early growth may also be critical for successful hemp cultivation under Louisiana’s regulatory and climatic conditions.

In a complementary controlled environment study, plants grown at 12°C produced less biomass than those at 22°C, indicating temperature significantly influences growth. However, cooler temperatures were associated with favorable cannabinoid profiles, particularly reduced THC levels. Cultivar-specific responses to temperature were observed, highlighting the importance of genotype selection in optimizing off-season hemp production.

Date

7-9-2025

Committee Chair

Fontenot, Kathryn

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