Vegetative Stage

The vegetative stage begins when the cannabis seedling develops its first set of true leaves (typically 7-10 days after germination) and ends when the grower triggers flowering by switching to a 12/12 light cycle. During veg, the plant focuses entirely on building structural mass: stems thicken, branches multiply, leaves expand, and root systems extend through the growing medium. Standard indoor veg parameters: 18/6 or 24/0 light cycle (some growers prefer 20/4 to save electricity while maintaining vigor), temperature 70-85°F (21-29°C), humidity 55-70% RH, EC of 1.0-1.6 mS/cm with elevated nitrogen ratios (NPK 3-1-2 or similar), and CO2 levels 400-1200 ppm. Plant size at the end of veg determines final yield potential — flowering causes plants to roughly double in size during the "stretch," so a 30cm plant flipped to flower will finish around 60-90cm tall. Veg duration varies by goal: SOG (sea of green) growers veg for just 1-2 weeks before flipping to maximize plants per square meter; SCROG (screen of green) growers veg for 4-8 weeks to fill a horizontal screen; mother plants are vegged indefinitely under continuous 18/6 light to provide cuttings for cloning. Autoflowers do not have a true vegetative stage — they begin flowering automatically 21-35 days after germination based on internal genetic timers, so growers cannot extend veg to increase yield.