How do pinching and plant density affect industrial hemp produced for cannabinoids in open field conditions?

Abstract

AbstractInformation regarding agronomic practices for field‐scale industrial hemp (IH) production for cannabinoids is extremely limited. The objective of this study was to investigate how pinching practice (i.e., removing the apical meristem) and varied plant density affect yield and cannabinoid production of IH in open field conditions. A field trial was performed in northern Florida in 2019 and 2020. The pinching study included pinch and non‐pinch treatments evaluated on two commercially available day‐length–sensitive IH cultivars Cherry Blossom (CBL) and Cherry Wine (CW). Four plant densities (3,000, 4,000, 6,000, and 12,000 plants ha–1) were evaluated on CW. The experimental design was a randomized complete block design with four blocks. Total flower yield in 2019 was two times greater than in 2020. In 2020, total tetrahydrocannabinol and cannabidiol (CBD) in CBL was significantly greater than in CW. Pinching did not significantly improve flower yield, cannabinoid concentration, or CBD production. Flower yield per plant decreased as plant density increased, but a reversed trend occurred for total flower yield per hectare. Cannabinoid concentration was not affected by plant density, but CBD production increased with increased plant density. Due to the high cost of IH plant material and labor, greater plant density does not always guarantee greater economic return. This study provides valuable information for field‐scale cultivation of IH for cannabinoids and supports the development of a large agricultural industry globally.