Flowering Stage
Part of the free Stevie Weedseed grow guide. No paywall, no account, written by a working grower.
Triggering Flower
Indoor: switch to 12 hours light, 12 hours UNINTERRUPTED darkness. The dark period must be complete. Light leaks cause stress, hermaphrodites, and reduced yields.
Outdoor: flowering begins naturally when daylight hours decrease (late summer). Autoflowers flower automatically regardless of light schedule.
Outdoor: flowering begins naturally when daylight hours decrease (late summer). Autoflowers flower automatically regardless of light schedule.
The Stretch
Weeks 1-3 of flower: plants can grow 50-100% taller. This is the "stretch." White pistils (hairs) appear at bud sites.
During stretch, the plant is still building structure. Some growers continue veg nutrients for the first week of flower, then transition to bloom.
During stretch, the plant is still building structure. Some growers continue veg nutrients for the first week of flower, then transition to bloom.
Flower Nutrients
Switch to a bloom or flower formula: higher phosphorus (P) and potassium (K), lower nitrogen (N).
NPK target: about 1-3-2 for early to mid flower, 0-3-3 for peak bloom.
CalMag is critical during flower. Calcium deficiency (brown spots) is common.
NPK Calculator for exact ratios →
NPK target: about 1-3-2 for early to mid flower, 0-3-3 for peak bloom.
CalMag is critical during flower. Calcium deficiency (brown spots) is common.
NPK Calculator for exact ratios →
Bud Development
Mid Flower (Weeks 4-6): Buds thicken, aroma intensifies, resin production ramps up. Humidity control becomes critical, keep it below 50%.
Late Flower (Weeks 7-10): Buds become dense and swollen, pistils darken and curl inward, trichomes mature. This is when you start checking trichomes daily with a loupe.
Late Flower (Weeks 7-10): Buds become dense and swollen, pistils darken and curl inward, trichomes mature. This is when you start checking trichomes daily with a loupe.
Preventing Bud Rot
Dense buds trap moisture. High humidity leads to mold and bud rot.
Prevention: Keep humidity 40-50% in flower, 30-40% in late flower. Constant airflow across the canopy. Do not water right before lights off. If you see gray or brown mold inside a bud, remove it immediately and check the surrounding buds.
Use the VPD Chart to prevent mold →
Prevention: Keep humidity 40-50% in flower, 30-40% in late flower. Constant airflow across the canopy. Do not water right before lights off. If you see gray or brown mold inside a bud, remove it immediately and check the surrounding buds.
Use the VPD Chart to prevent mold →