The cannabis life cycle has four stages: germination and seedling establishment, vegetative growth, flowering, and seed formation. Cannabis is an annual plant, so it completes all four in a single season, and the shift from vegetative growth to flowering is triggered mainly by the length of the night. Growers add a fifth step, harvest, which they time before the plant finishes setting seed.
Botanists describe cannabis as an annual, herbaceous plant that is predominantly outcrossing, meaning plants usually pollinate each other, and native to the Tibetan Plateau region (Betancourt et al., Plants, 2026). That four-stage cycle is the frame for everything growers do, from choosing a light schedule to deciding when to cut. This guide walks through each stage and what research says about it.
The Cannabis Life Cycle at a Glance
| Stage | What happens | What the research adds | Source |
|---|---|---|---|
| 1. Germination and seedling | The seed sprouts and the plant establishes its first roots and leaves | Seedlings and clones do best at the higher end of the humidity range, 65 to 75% | Betancourt et al., 2026; Corredor-Perilla et al., 2025 |
| 2. Vegetative growth | Stems, branches and fan leaves build the plant | Indoor schedule of 16 hours of light and 8 of dark; humidity 50 to 70% | Ijoma et al., 2025; Corredor-Perilla et al., 2025 |
| 3. Flowering | Flowers form on female plants; resin glands fill | Triggered when days drop below about 12 hours; humidity 40 to 60% | Backer et al., 2019; Corredor-Perilla et al., 2025 |
| 4. Seed formation | Pollinated flowers develop seeds | Pollination lowers cannabinoid content, so growers of flower remove males | Babaei and Torkamaneh, 2026 |
Stage 1: Germination and the Seedling
Everything starts with a seed. When it receives moisture and warmth, the seed splits and sends out a root, then pushes its first leaves up toward the light. This is the most fragile phase. The humidity literature recommends 65 to 75% relative humidity for the clone and seedling stage, higher than later stages, because young plants have small root systems and lose water through their leaves (Corredor-Perilla et al., 2025).
The seedling stage ends when the plant begins growing in earnest. If you want a closer look at the first days, our guide to germinating marijuana seeds covers the methods in depth.
Stage 2: Vegetative Growth
In the vegetative stage the plant builds leaves, stems and roots. It is the stage growers control most directly. Cannabis is a photoperiod-sensitive, short-day plant, so growers keep days long to keep it vegetative. A 2025 study notes that cultivators must extend the photoperiod to maintain vegetative growth long enough to grow a healthy, vigorous plant before the reproductive phase begins (Grover et al., Plants, 2025). One indoor protocol uses 16 hours of light and 8 of dark at this point (Ijoma et al., J Cannabis Research, 2025).
This is also when training takes place. Cannabis is apically dominant, meaning it favors one main stem. Topping and bending create a wider canopy, and growers typically do this early in vegetative growth, around five or six nodes, and stop before flowering (Ijoma et al., 2025). Details are in our guides to scrogging and trellising and trimming cannabis plants.
Stage 3: Flowering
Flowering is where the plant earns its reputation. A 2019 meta-analysis reports that flowering is induced when day length is shorter than 12 hours (Backer et al., Frontiers in Plant Science, 2019). A 2025 review is more precise: cannabis is a facultative short-day plant that starts flowering at day lengths of about 9 to 15 hours, and at least three days of short days are needed to start and sustain flower formation (Corredor-Perilla et al., 2025). Outdoors this happens as autumn nights lengthen. Indoors, growers switch to 12 hours of light and 12 of dark.
Female flowers are structurally simple. A pistillate flower has a reduced outer layer and a bract that wraps around the ovary and its two stigmas, and the resin glands called trichomes cluster on that bract (Betancourt et al., 2026). Gland density rises from the first week of flowering, and the most productive gland type, the capitate-stalked trichome, differentiates roughly 15 to 20 days after flowering begins. Glands reach maturity, defined by peak cannabinoid accumulation, around five weeks after they start forming, and later in flowering some gland heads open and release resin (Betancourt et al., 2026).
Conditions matter. In one 2025 experiment, a plant at 78 to 98% relative humidity flowered later and had lower cannabinoid levels than a plant at 37 to 58% (Corredor-Perilla et al., 2025). Flowering time also differs by strain: our guides list about 7 to 9 weeks for Northern Lights, 8 to 9 weeks for OG Kush and 9 to 10 weeks for Blue Dream.
Stage 4: Seed Formation, and Why Growers Harvest First
In nature the cycle finishes when pollinated female flowers form seed. For people growing for buds, that is the outcome to avoid: researchers separate males from females before flowering because pollination reduces cannabinoid content (Babaei and Torkamaneh, Plant Genome, 2026). Growers instead watch for maturity cues. The 2026 landrace study used browning stigmas and a change in trichome color from clear to amber or brown, and the 2025 review says harvest typically comes when about 60 to 70% of trichomes are amber, with the timing varying by cultivar and conditions (Babaei and Torkamaneh, 2026; Ijoma et al., 2025).
How Long Does the Whole Cycle Take?
No single figure applies. The vegetative stage lasts as long as the grower keeps long days, and flowering lasts as long as the cultivar needs. As a rough guide, add the vegetative time you choose to the flowering time listed for your cultivar. For one 2025 indoor protocol, the first topping came about two weeks into vegetative growth, which gives a sense of how fast young plants move (Ijoma et al., 2025).
The same research warns against over-generalizing. Outdoors in the same study, harvest came roughly 6 to 8 months after planting, and the authors stressed that this is not a universal timeline (Ijoma et al., 2025).
Growing at Home: Washington and Oregon Law
Home growing is legal for adults 21 and older in Oregon, up to 4 plants per household, kept out of public view; see the statute (ORS 475C.305) and our Oregon marijuana laws guide. In Washington, home growing is legal only for registered medical patients. Under RCW 69.51A.210, a patient entered in the state medical cannabis authorization database may grow up to six plants by default, or up to fifteen if a health care professional recommends it. Adults who buy only at retail stores may not grow. See our Washington marijuana laws guide. Cannabis remains illegal under federal law, and local rules and landlord or HOA restrictions can add limits.
Cannabis Plant Life Cycle FAQ
What are the stages of the cannabis life cycle?
Germination and seedling, vegetative growth, flowering and seed formation. Growers add harvest, which comes when flowers mature and before seed sets.
What triggers cannabis to flower?
Shorter days. Flowering is induced when day length falls below about 12 hours, and the plant needs at least three days of short photoperiod to start. Indoors, growers use a 12/12 light schedule.
Is cannabis an annual or perennial?
Annual. Cannabis completes its cycle in a single season and then dies.
Do male and female plants differ in the life cycle?
Yes. Cannabis is predominantly dioecious, with separate male and female plants. Only females make the resin-rich flowers, and males are removed from flower crops to prevent pollination.
When is cannabis ready to harvest?
When the stigmas have browned and about 60 to 70% of the trichomes have turned amber, per one 2025 review. Exact timing depends on the cultivar.
Are there strains that flower faster?
Flowering time varies by strain. See our indoor strain picks and the strain directory for typical times.
For adults 21+ in legal states. General information, not medical advice.
