Commercial cannabis requires extraordinary photosynthetic photon flux densities (PPFD >1000 µmol/m²/s) and tight VPD control across distinct phenological stages: vegetative (0.9–1.1 kPa), early flower (1.1–1.3 kPa), and late ripening (1.3–1.6 kPa) to prevent bud rot (Botrytis) while maximizing cannabinoid and terpene synthesis.
Maintaining a DIF of +6 to +8°C (Day Temperature minus Night Temperature) regulates internode length and crop balance. When vegetative vigor is excessive, reducing DIF steers the plant toward reproductive flowering; increasing DIF restores leaf expansion and canopy Light Extinction (Beer-Lambert k-factor).
Target root-zone drain fraction: 20 - 30% to avoid substrate EC accumulation and root hypoxia.
Primary Pathological Risks: Botrytis (Bud Rot), Powdery Mildew, Two-spotted Spider Mite, Root Aphids, Russet Mites.
Biological Predator Sizing & Release Strategy: Phytoseiulus persimilis, Amblyseius andersoni, Dalotia coriaria (Rove Beetle), Beauveria bassiana.
Use Inwoovation Lab's free, browser-based calculators to model exact thermodynamics for your Cannabis crop:
Raising VPD to 1.3–1.5 kPa lowers relative humidity (RH 45–55%), which dramatically suppresses conidial germination of Botrytis cinerea within dense floral clusters without stalling transpiration.