What is the cannabis flowering stage?
The cannabis flowering stage is the reproductive phase when a plant stops stretching upward and starts building buds. It starts when photoperiod plants get 12 hours of uninterrupted darkness per day, or about 3 to 4 weeks after an autoflower seed sprouts. Flowering lasts roughly 8 to 11 weeks and ends at harvest, when trichomes turn cloudy or amber.
Cannabis Flowering Stage: Humidity and Temperature Guide
How long does the cannabis flowering stage last?
Most photoperiod strains flower for 8 to 11 weeks after the light schedule flips to 12 hours on and 12 hours off. Autoflowers run on their own clock and usually finish 8 to 10 weeks from seed, with 5 to 7 of those weeks spent in flower.
cannabis flowering stage yellow leaves
- Indica-dominant: 7 to 9 weeks
- Balanced hybrids: 9 to 10 weeks
- Sativa-dominant: 10 to 14 weeks
Cannabis flowering stage week by week
- Weeks 1 to 2, transition: Vertical stretch peaks, pre-flowers show at the nodes, and the first white pistils appear. Nitrogen demand stays high.
- Weeks 3 to 4, early flower: Bud sites cluster into colas and phosphorus and potassium needs climb. Stretch slows and internodes stop spacing out.
- Weeks 5 to 7, mid flower: Buds swell and pack on weight, so support heavy branches before they bend. Keep humidity between 40 and 50 percent to limit bud rot.
- Weeks 8 to 10 and beyond, ripening: Pistils darken and curl inward, calyxes tighten, and trichomes shift from clear to cloudy. This is the window for flushing and a final harvest check.
What do cannabis plants need during flowering?
Light schedule
Photoperiod plants need 12 hours of dark and 12 hours of light with zero light leaks, since a single interruption can trigger hermaphrodites. Keep intensity high enough to drive bud density, but raise the light if leaf tips bleach.
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Nutrients and pH
Cut nitrogen and shift toward phosphorus and potassium as buds form. Most cannabis soils and reservoirs perform best between pH 6.0 and 6.5, and feeding strength should peak in mid flower then taper.
Outdoor Cannabis Flowering Month: When Plants Start to Bloom
Temperature and humidity
Aim for 68 to 78 degrees F with 40 to 50 percent relative humidity. Cooler nights in late flower help preserve terpenes, and steady airflow around every cola is the cheapest defense against mold.
How do you know when to harvest cannabis?
Judge ripeness with a magnifier on the calyxes, not the sugar leaves. Clear trichomes mean the plant is early, all-cloudy heads mark peak THC, and amber heads signal rising CBN and a heavier body effect. Most growers harvest when heads are cloudy with 10 to 20 percent amber and 60 to 70 percent of pistils have darkened.
Common flowering stage problems
- Nutrient burn: dark clawed tips that crisp and curl
- Bud rot: gray fuzz inside dense colas, usually from high humidity
- Light leaks: seeded buds and male flowers on female plants
- Heat stress: foxtailing, bleached tips, and thin aroma
FAQ
Can you flip cannabis to flower early?
Yes. Flipping at 12/12 from seed keeps plants short and speeds up the timeline, though yield drops. Most growers veg 4 to 8 weeks to balance size against total time.
Do autoflowers have a flowering stage?
Autoflowers flower automatically at about 3 to 4 weeks of age regardless of light schedule. They still pass through the same bud-building phases, just faster and without a photoperiod trigger.
Does the flowering stage change THC levels?
THC accumulates through mid and late flower and peaks near full trichome cloudiness. Harvesting early caps potency, while waiting too long converts THC toward CBN and dulls the high.
Flowering stage at a glance
Expect 8 to 11 weeks of bud development, peak feeding in mid flower, and a harvest decision based on trichome color. Licensed shops such as Eden Cannabis stock lab-tested flower that lists its strain, potency, and terpene profile, which makes it easier to match the finished buds to what you grew or plan to grow.