Greenhouse

Greenhouse cultivation is a hybrid modality in which cannabis is grown under a translucent enclosure — glass, polycarbonate, or polyethylene film — that admits solar PAR while providing structural protection from wind, precipitation, and many pests. Commercial cannabis greenhouses typically combine solar radiation with light deprivation (blackout systems that mechanically shorten photoperiod to force flowering outside the natural season), supplemental lighting (HPS or LED fixtures deployed when solar daily light integral falls below target), environmental control (heating, cooling, dehumidification, CO₂), and sometimes rolling benches (Eichhorn Bilodeau et al. 2019, Frontiers in Plant Science 10:296, "An update on plant photobiology and implications for cannabis production"). Greenhouse production reduces lighting energy by roughly 50% versus indoor and enables 3–5 harvests per year at appropriate latitudes, though cannabinoid potency and consistency are typically intermediate between indoor and outdoor. Etymology: English "green" + "house," 17th-century horticultural usage. Synonyms/slang: glasshouse, hoop house, light-dep, mixed-light. → See also: Indoor, Outdoor, Photoperiod.