HST (High-Stress Training)

High-stress training (HST) encompasses any training technique that intentionally wounds, breaks, or removes plant tissue to manipulate growth patterns. The "stress" refers to the plant's wound response — when damaged, cannabis releases stress hormones that trigger compensatory growth, including new branching, denser node spacing, increased trichome production, and stronger cell wall development at injury sites. Common HST techniques: (1) Topping — cutting the apical tip to create two main colas; (2) Fimming — partially cutting the apical tip for 3-4 new colas; (3) Supercropping — pinching and bending branches until the internal fibers crack but the outer skin remains intact, creating knuckle-like swelling; (4) Mainlining — combining topping with strict symmetry to create 8-32 evenly sized colas; (5) Defoliation — strategically removing fan leaves to increase light penetration to lower bud sites; (6) Lollipopping — removing all lower branches and growth to focus energy on upper colas. HST is more aggressive than LST (low-stress training) but produces stronger yield gains and more compact plant structures when executed properly. Critical timing rules: HST should only be performed during vegetative growth, with at least 7-14 days of recovery before flipping to flowering. HST during flowering causes irreversible yield loss and stress-induced hermaphroditism. Autoflowers should generally avoid HST since their fixed lifecycle prevents adequate recovery. The skill requirement is also higher — a poorly executed supercropping move can snap a branch entirely, while improper defoliation can stunt plants for weeks.