Environmental Factors Humidity

Humidity management is a critical environmental variable in cannabis cultivation that influences plant physiology, disease pressure, and cannabinoid/terpene expression. Relative humidity (RH) levels during vegetative growth, flowering, and drying phases affect transpiration rates, nutrient uptake, and the development of secondary metabolites. High humidity environments increase susceptibility to powdery mildew, botrytis, and other fungal pathogens, while low humidity can stress plants and reduce yields. Breeders and cultivators document how different genetic lineages respond variably to humidity stress—some cultivars show enhanced resilience to high-moisture conditions, while others thrive in drier climates. Understanding humidity as an environmental factor helps explain phenotypic variation within a strain family and informs cultivation protocols across different geographic regions.

Cannabis breeders select for humidity tolerance and disease resistance by testing parent plants and offspring under controlled moisture conditions. Lineages commonly associated with outdoor cultivation in humid regions have been selected for powdery mildew resistance and faster bud maturation to reduce fungal pressure.