Soil

Soil in cannabis horticulture denotes a particulate, pedogenic or engineered substrate composed of mineral fractions (sand, silt, clay), organic matter (peat, compost, leaf mold), and a biotic community of bacteria, archaea, fungi, and microfauna that mediate nutrient cycling. Unlike inert hydroponic media, soil provides cation exchange capacity (CEC), buffering of pH and nutrient availability, and symbiotic microbiology (mycorrhizae, rhizobacteria) (Backer et al. 2019). "Living soil" or no-till organic systems amend a base substrate with compost, worm castings (vermicompost), bat or seabird guano, kelp meal, alfalfa meal, rock dusts, and biochar, cycling nutrients via microbial mineralization rather than synthetic fertigation. Cannabis in soil typically requires lower fertigation frequency than in coco or hydroponic systems and may accumulate a distinct terpene profile, though peer-reviewed comparative data remain limited (Chandra et al. 2017; Caplan et al. 2017a). Etymology: Old French soille, Latin solum ("ground"). Synonyms/slang: dirt, medium, living soil, super-soil. → See also: Coco coir, Hydroponic, Outdoor.