Stretch Ratio

Stretch ratio describes the vertical growth pattern of cannabis during the flowering phase, typically measured as the relationship between plant height at flowering initiation and final mature height. Cannabis plants commonly stretch 50-300% during early flower, driven by genetic programming and environmental factors including light intensity, photoperiod, and temperature. Stretch ratio varies significantly across strain families—sativas often exhibit extended stretch while indicas typically show more compact growth. Understanding stretch characteristics is essential for indoor cultivation planning, as inadequate ceiling height or miscalculation of final plant dimensions can compromise yields and canopy management. Breeders document stretch ratios when developing cultivars for specific growing environments and production systems.

Breeders working in controlled-environment agriculture prioritize stretch ratio as a key selection trait, particularly when developing cultivars for vertical farming, Sea of Green (SOG), or other space-constrained systems. Predictable, moderate stretch ratios enable more consistent crop planning and help optimize light distribution across canopy layers.