How Long Weed Takes to Grow From Seed to Harvest

Written by Sipho Sam

September 30th, 2025

Cannabis takes 3 to 8 months total from seed to smokeable flower, not the 8-10 weeks printed on most seed packs.

That marketing number only describes the flowering phase after plants show pistils, completely ignoring the weeks of germination, seedling growth, and vegetative development that come first.

Plus another month for drying and curing, which makes the difference between harsh grass and smooth smoke.

Here's what happens: autoflowers typically need 85-110 days from seed to harvest, photoperiods run 4-6 months indoors, and outdoor grows follow the seasons for 5-8 months total.

This guide breaks down every stage with realistic timelines you can put on a calendar, visual cues to track progress, and the truth about when plants smell, stretch, and demand full resources.

Laws vary by US state, and this information is for educational purposes only - learn how weed is legal.

Table of Contents

• Cannabis takes 3 to 8 months total (here's the real timeline)

• Each growth stage and exactly how long it lasts

• Why your plants double in size after you flip them

• Reading trichomes to time your harvest perfectly

• The 4 to 6 weeks after harvest nobody mentions

• When smell kicks in and power use peaks

• Actually fast methods that aren't fantasies

• Indoor vs outdoor timing differences

• How genetics affect your total timeline

• Two complete calendars you can actually use

• Quick timing answers for common questions

• Skip the wait with ready-to-enjoy options

Cannabis takes 3 to 8 months total (here's the real timeline)

Forget everything the seed pack promises.

Autoflowering cannabis actually takes 85-110 days from seed to harvest, even when breeders claim 8-10 weeks.

Photoperiod plants need 4-6 months total for indoor grows, while outdoor cultivation runs 5-8 months following natural seasons.

Complete Timeline Breakdown:

• Germination: 1-7 days (seed cracks, taproot emerges)

• Seedling: 2-3 weeks (first leaves develop)

• Vegetative: 2-8+ weeks (rapid growth phase)

• Flowering: 6-12 weeks (buds form and mature)

• Drying: 7-14 days (moisture removal)

• Curing: 2-4+ weeks minimum (flavor development)

The confusion starts because "flowering time" on seed packets only counts from when pistils appear until harvest.

Breeders conveniently skip the 3-8 weeks before flowering and the month of post-harvest processing.

Community growers consistently report adding 1-2 weeks beyond breeder estimates for proper maturity.

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Each growth stage and exactly how long it lasts

The seedling stage spans 2-3 weeks from sprout until plants develop their first set of true fan leaves with 5-7 fingers.

During this phase, stems stay thin and fragile while plants establish root systems and grow 3-4 nodes tall.

Vegetative growth kicks in around week 3 and continues for 2-8+ weeks, depending on your chosen timeline.

Plants grow during veg, developing thick stems, multiple branches, and dense foliage.

New nodes appear every 3-5 days, and fan leaves reach full size.

The pre-flowering transition shows sex characteristics, with white pistils for females and pollen sacs for males.

This appears 1-2 weeks after switching photoperiods to 12/12 light or automatically in autos around week 3-5.

Early flowering (weeks 1-3 of bloom) brings the stretch period, where vertical growth accelerates.

Mid-flowering (weeks 4-6) sees bud sites filling out and trichome production beginning - advanced extractors turn these trichomes into products like liquid diamonds THCa.

Late flowering (weeks 7+) brings density, aroma intensification, and trichome maturation.

Why your plants double in size after you flip them

The flowering stretch hits the first 2-3 weeks after flipping to 12/12 light.

Plants can double or even triple their height during this explosive growth phase.

A 24-inch plant entering flower commonly reaches 48-72 inches by week 3 of bloom — quite different from plants that look like weeds but don't grow the same.

This catches new growers completely off guard when plants outgrow their tents.

Indoor growers must account for this stretch when planning their vegetative timeline.

If your tent is 6 feet high and your light needs 18 inches of clearance, you can only let plants reach about 20-24 inches before flipping.

Training techniques like topping, LST, and ScrOG help manage height during the stretch.

Some sativa-dominant strains stretch more aggressively than indica varieties.

Reading trichomes to time your harvest perfectly

Trichomes progress from clear to milky to amber, and this color change determines harvest timing - similar precision matters when comparing THCp vs THCa.

Clear trichomes mean compounds haven't fully developed, which results in different effects if harvested.

Milky or cloudy trichomes indicate peak potency and the prime harvest window for most growers.

Amber trichomes signal compounds are changing, creating different effects.

Most growers harvest when trichomes show 70-90% milky with 10-30% amber.

Pistils provide a secondary indicator where you harvest when 50-70% have darkened and curled inward.

The harvest window typically spans 2-3 weeks, and waiting toward the end often adds 10-20% more weight.

You'll need a jeweler's loupe or digital microscope (30-60x magnification) to examine trichomes properly.

The 4 to 6 weeks after harvest nobody mentions

Drying takes 7-14 days in a controlled environment at 60-65°F with 45-55% humidity.

Branches should snap cleanly rather than bend, and outer buds feel dry while stems retain slight moisture.

Rushing the dry ruins terpenes, creating harsh smoke that tastes like fresh-cut grass.

Curing requires at least 2-4 weeks in airtight jars, though 2-3 months brings out maximum flavor.

Open jars daily for the first week ("burping") to release moisture and prevent mold.

After week one, burp jars every few days, then weekly as the cure progresses.

The grassy smell fades around weeks 2-3 of curing as chlorophyll breaks down. Meanwhile, modern products like infused weed skip this wait entirely.

Proper drying and curing transform harsh, green-tasting flower into smooth, flavorful smoke.

Understanding this process helps you appreciate the best THCa flowers online.

Many new growers destroy months of work by rushing these final weeks.

When smell kicks in and power use peaks

Cannabis starts producing noticeable odor during late vegetative growth, around week 4-6 from seed.

The smell intensifies dramatically when flowering begins, becoming unmistakable by week 2-3 of bloom.

Carbon filter systems become essential from late veg through harvest.

Power consumption peaks during late veg and flowering when lights run at maximum intensity.

An average 4x4 tent setup continuously pulls 400-600 watts during peak growth.

Water and nutrient demands also spike during the flowering stretch and mid-bloom bud development.

Temperature control becomes critical during flowering, keeping it 68-78°F with 40-50% humidity.

These resource peaks typically hit weeks 6-14 of the total growth cycle.

Actually fast methods that aren't fantasies

The absolute fastest realistic timeline uses autoflowers harvested at the early end of their window, around 75-85 days.

This sacrifices some yield and potency but delivers results in under three months.

12/12 from seed photoperiods skip the extended veg phase, finishing in 3-4 months.

Plants stay small (1-2 ounces), but the timeline compresses significantly.

Deep water culture (DWC) and hydroponic systems accelerate growth by 20-30% versus soil.

Starting from clones eliminates 2-3 weeks of germination and early seedling time.

Sea of Green (SOG) methods pack many small plants for faster turnover.

The "8 weeks seed to harvest" claim remains pure fantasy since even the fastest methods need 10-12 weeks minimum.

Every speed technique trades something: yield, potency, or plant count.

Indoor vs outdoor timing differences

Indoor growing typically produces harvest-ready plants in 3-5 months from seed.

You control the vegetative period by maintaining 18/6 or 24/0 light schedules.

Flip to 12/12 whenever plants reach your desired size, usually after 3-8 weeks of veg.

Outdoor plants follow natural photoperiods, taking 5-8 months from spring planting to fall harvest.

Northern hemisphere outdoor growers plant in April-May and harvest in September-October.

Plants vegetate through the long summer days, then flower as daylight hours decrease.

Light-deprived greenhouses let outdoor growers force flowering early by blocking light.

This technique can shave 4-6 weeks off the outdoor timeline.

How genetics affect your total timeline

Indica-dominant strains typically flower for 7-9 weeks after showing pistils.

Similar timing differences exist between vape pens and flower highs.

Their compact structure and faster maturation make them popular for indoor growing.

Sativa-dominant varieties often need 10-14 weeks of flowering, sometimes longer.

Pure sativas can stretch the timeline to 6-7 months from seed.

Autoflowering genetics incorporate ruderalis traits that trigger flowering by age rather than light - learn what THCa is.

Despite "8-10 week" marketing, autos consistently need 85-110+ days in real grows - this reality explains why all weed starts as THCa.

Feminized seeds eliminate time spent identifying and removing male plants.

Regular seeds may produce 40-60% males that waste space and nutrients before removal.

Two complete calendars you can actually use

Autoflower Example Timeline:

• April 1: Germinate seeds

• April 3-7: Seedlings emerge

• April 7-28: Seedling/early veg phase

• May 1-5: Pre-flowers appear

• May 5 - June 20: Flowering phase

• June 20-25: Check trichomes, harvest when ready

• June 25 - July 5: Drying

• July 5 - August 1: Curing

• August 1: First quality smoke

Indoor Photoperiod Example:

• April 1: Germinate seeds

• April 3-7: Seedlings emerge

• April 7-28: Seedling phase (18/6 light)

• May 1-31: Vegetative growth (18/6 light)

• June 1: Flip to 12/12 flowering

• June 1-15: Flowering stretch

• June 15 - August 1: Bud development

• August 1-7: Harvest window

• August 7-20: Drying

• August 20 - September 20: Curing

Adjust these timelines based on your specific strain, growing medium, and environmental conditions.

Add 1-2 weeks buffer for slower phenotypes or unexpected issues.

Quick timing answers for common questions

When do I start counting flowering time? Count from when you see the first white pistils, not from flipping the lights.

How long do autoflowers really take? Expect 85-110 days from seed to harvest despite 8-10 week marketing claims.

When will my plants start to smell? Noticeable odor begins in late veg (week 4-6) and intensifies dramatically by week 2 of flowering.

Can I harvest based on the breeder timeline? Add 1-2 weeks minimum to any breeder estimate and check trichomes for actual readiness.

How long should I veg photoperiods? Most indoor growers veg for 4-8 weeks, but you can flip anytime after week 3.

When do plants stop growing taller? Vertical growth typically stops by week 3-4 of flowering after the stretch completes.

How long does the smell last after harvest? Properly dried and stored flower maintains aroma for 6-12 months.

Skip the wait with ready-to-enjoy options

Growing cannabis demands 3-8 months of consistent attention, space, and resources.

Not everyone has the time, space, or situation that allows for months of cultivation.

If you need effects sooner or prefer avoiding the growing process entirely, quality alternatives exist.

Mood's flower collection delivers the same compounds found in homegrown, ready to enjoy immediately.

Our Delta-8 gummies provide consistent effects without any cultivation time.

Both paths serve different needs and timelines, whether you grow your own or choose quality products.

Your grow timeline starts now

You now understand the timeline: 3-8 months total, not 8-10 weeks.

You know to watch trichomes instead of calendars, plan for the stretch, and never rush drying and curing.

Copy one of the sample calendars above and adjust it after your first run teaches you strain-specific timing.

Whether you commit to months of growing or choose ready-made options, you're making an informed decision.

The difference between success and disappointment often comes down to having realistic expectations from day one.

Start your timeline with truth, not marketing, and you'll avoid the frustration that comes from believing the 8-week fantasy.