Effect of temperature, relative humidity and gibberellic acid on seed germination and early growth of industrial cannabis seedlings (Cannabis sativa L.)

The current study evaluated the effect of temperature, relative humidity and gibberellic acid on seed germination and early growth of the industrial hemp Cannabis sativa L. ‘Santhica 70’. The experiments were conducted into a fully automated growth chamber (16-h photoperiod). We examined the effect of temperature at 10, 15, 20, 25, and 30°C under relative humidity 65%, the effect of relative humidity levels (45, 55, 65, 75, and 85% RH) under 20°C and the impact of gibberellic acid (GA₃) at 0, 100, 300, 500, and 700 mg L^‑1 concentrations.
On the sixth day of experiments, germination percentage (GP), germination rate index (GRI), mean germination time (MGT), and coefficient of velocity of germination (CVG) were evaluated.
The present results show that the optimal conditions for seed germination are temperature of 20°C and relative humidity of 65% (93.3% germination percentage). GRI peaked at 20°C and 75% humidity (76.1% day^‑1), with a GA₃ concentration of 500 mg L^‑1. MGT decreased from 10 to 30°C (2.9 to 1.1 days), while CVG increased within the same temperature range (34.9 to 95.2), with no statistically significant variations observed in relative humidity and GA₃ effects.
This methodology provides vital insights to optimizing seed germination practices and seedling growth of Cannabis sativa L.

I International Symposium on Protected Cultivation, Nettings and Screens for Mild Climates

S. Chavalina, G. Zervoudakis, D. Bilalis, G. Salahas

hemp, germination percentage, germination rate index, mean germination time, coefficient velocity of germination

https://doi.org/10.17660/ActaHortic.2025.1437.53