ASHS 2025 Conference

Cannabis (Cannabis sativa L.) is an annual herbaceous plant that belongs to the Cannabaceae family and produces economically important secondary metabolites called cannabinoids. According to the literature, controlled or induced water-deficit stress can increase secondary metabolite concentration in some essential oil-producing plants. Therefore, induced water-deficit stress (DS) may be an effective technique to maximize cannabinoid yield. This study investigated how different frequencies of induced water-deficit stress during the flowering stage affect cannabinoid yield and cannabis development compared to well-irrigated controls. By exploring the optimal stress conditions conducive to maximizing cannabinoid production, our study aims to offer strategic insights to inform cultivation practices and optimize cannabinoid production. This research contributes to advancing our understanding of cannabis cultivation techniques and may ultimately enhance the efficiency and efficacy of cannabinoid production on a commercial scale. Our hypothesis posits that induced water-deficit stress enhances plant secondary metabolism by modulating physiological responses. The treatments consisted of four frequencies of water-deficit stress periods during the cannabis flowering stage: WS0 – no stress, WS1 – one period of water-deficit stress, WS2 – two periods of water-deficit stress, and WS3 – three periods of water-deficit stress. The experiment was conducted using clones of the Heidi cultivar, which were randomly placed in the controlled-environment growth units. Weekly plant parameters included plant height, stem diameter, NDVI, chlorophyll content, photosynthetic efficiency, and stomatal conductance. After-harvest parameters included biomass partitioning, yield mass, bucked biomass, trichome density, and cannabinoid and terpenes levels. This is an ongoing study, but the preliminary data analysis shows interesting results regarding higher trichome density with no penalty for bucked biomass in the treatments under one period of water-deficit stress (WS1).