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Why Autoflowers Take 8 Weeks and Photoperiods Take 6 Months
Autoflowers really take 10-12 weeks, not 60 days. Learn actual cannabis timelines, the 'add two weeks' rule, and how fast-flipped photos match auto timing.
Written by Sipho Sam
October 3rd, 2025
Here's the truth most seed banks won't tell you: those "8-week autoflowers" typically finish in 10-12 weeks, and sometimes stretch to 13-14.
Meanwhile, photoperiods don't have to take 6 months. We've seen growers match auto timing by flipping early and finishing in 11-13 weeks.
The cannabis community has a universal correction for breeder timelines: add two weeks, minimum.
We're breaking down the actual calendars you can trust, along with the handful of decisions that genuinely impact your harvest date.
Table of Contents
Real Autoflower and Photoperiod Timelines From Seed to Harvest
Where Every Week Goes in Your Growing Cycle
Why Autoflowers Bloom Automatically and Photoperiods Wait for You
Two Proven Ways to Harvest in 12 Weeks
Growing Mistakes That Secretly Add Weeks to Your Timeline
Potency and Electricity Costs per Harvest Timeline
When to Actually Harvest Based on What You See
Your Complete Growing Calendar Mapped Out
Quick Answers About Growing Timelines
Growing Laws and Final Timeline Tips
Real Autoflower and Photoperiod Timelines From Seed to Harvest
Autoflowers typically finish in 10-12 weeks from seed, with 13-14 week runs surprisingly common despite those optimistic "60-70 day" promises on the package.
Photoperiods usually take 12-20+ weeks with standard vegetative periods, but here's what changes everything: flip them early and they'll finish in 11-13 weeks.
These timelines only cover the seed-to-chop stage. Add 7-14 days for drying, followed by a minimum of 2-8 weeks for curing and proper storage before your jars are ready for use.
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Where Every Week Goes in Your Growing Cycle
Every cannabis plant moves through the same phases: seedling, vegetative, flowering, and then post-harvest processing. The difference lies in who controls the clock.
With photoperiods, vegetative time becomes your variable. Run it for two weeks or two months, your choice entirely.
Marketing conveniently skips those final 3-8 weeks of drying and curing that stand between harvest and smokable flower.
The Autoflower Timeline Breakdown
The seedling stage runs 1-2 weeks while your plant establishes its first true leaves. Vegetative growth lasts 2-4 weeks, regardless of the conditions - this phase is genetically predetermined.
Flowering kicks in automatically around week 3-5 and continues for 6-8 weeks. Your 10-12 week total assumes everything goes smoothly, which it rarely does on your first few runs.
The Photoperiod Timeline With Options
The seedling stage takes 2-3 weeks for the plants to establish strong roots. Vegetative phase runs anywhere from zero weeks (12/12 from seed) to 8+ weeks for massive plants. You control this completely.
Flowering begins when you switch to 12/12 lighting and runs 7-12+ weeks depending on genetics.
Sativa-dominant strains push toward the longer end while indica-heavy genetics finish faster.
Why Autoflowers Bloom Automatically and Photoperiods Wait for You
Autoflowers carry Ruderalis genetics that trigger flowering based on age, rather than light cycles.
Photoperiods require a 12-hour darkness signal to start blooming. They'll stay in vegetative growth forever under 18+ hours of light.
We see this confusion weekly: running autoflowers at 12/12 doesn't accelerate their growth.
You're simply cutting their daily energy intake by 30-40%, which results in smaller plants that finish on the same schedule.
One more planning note: photoperiods typically double in height after you flip to flower. That "flowering stretch" catches new growers off guard when their 2-foot plant suddenly pushes toward the tent ceiling.
If you're curious about how THCa flower is cultivated, professional growers follow similar principles during the flowering stage to maximize cannabinoid production.
How to Tell Autoflower From Photoperiod
Autoflowers exhibit sex and begin flowering around week 3-5, regardless of the light schedule.
Photoperiods only flower when you switch to 12/12 lighting or when outdoor daylight naturally shortens.
Understanding the differences between cannabis strains can help you choose the right genetics for your timeline goals.
Will 12/12 Stunt an Autoflower?
Yes, running 12/12 stunts autoflower growth by reducing their total light intake, but it won't change their harvest date. Stick with 18/6 or 20/4 for healthy auto development.
Watch: How To Use Cannabis Flower
Two Proven Ways to Harvest in 12 Weeks
The standard auto path uses 18/6 or 20/4 lighting throughout the entire 10-12 week cycle.
You have less control over plant shape and size, but the process remains simple - set your timer once and let genetics take care of the rest.
The fast-flip photo path starts with 12/12 lighting from seed or after just one week of vegetative growth.
This approach typically takes 11-13 weeks, allowing you to have more control over canopy development through training.
If timing certainty matters while you're learning the ropes, our THCa flower selection ships predictably.
Consider it a bridge between harvests or a backup when experiments run long. For even more convenience, check out our pre-rolls, no grinding or rolling required.
Is It Better to Grow Autoflower or Photoperiod?
Neither type is universally "better." It depends on your constraints. Choose autos for simplicity and predictable timing, or photos for maximum control and yield potential.
Growing Mistakes That Secretly Add Weeks to Your Timeline
Autoflower killers include transplant shock, which can permanently stunt growth since autos lack the recovery time before flowering starts.
Overfeeding during weeks 1-4 can burn delicate roots and slow everything down.
Heavy training techniques work great on photos, but cripple autos that can't bounce back. Never attempt cloning with autos. The clones inherit the mother's age and immediately flower at 2 inches tall.
Photoperiod delays result from light leaks that disrupt the flowering cycle, forcing plants back into vegetative growth.
Timer failures that accidentally switch back to 18/6 can trigger revegging, adding weeks to your timeline.
When growing feels overwhelming, exploring premium concentrates can offer a shortcut to quality experiences.
What Stunts Autoflower Growth?
Early stress stunts autos permanently. Transplanting, overwatering, using aggressive nutrients, or heavy defoliation in the first month creates problems they can't overcome.
Start in the final containers with gentle feeding.
What Is the Disadvantage of Autoflowers?
Autoflowers offer zero timeline flexibility once planted and can't recover from early mistakes. You also can't clone them or extend vegetative growth for bigger yields.
Potency and Electricity Costs per Harvest Timeline
Modern autoflowers typically test at 20-24% THC, while photoperiods can push 25-30% with optimal genetics and growing conditions. The gap has narrowed considerably as auto-breeding improves.
Energy costs tell a different story: autos need 18-20 hours of light daily throughout their cycle.
Photos use that same schedule during veg but drop to 12 hours during the longer flowering phase.
Flowering length varies by genetics, too. Indica-dominant strains typically finish flowering in 6-8 weeks while sativa-heavy varieties run 8- 12+ weeks.
Do Autoflowers Yield More?
Autoflowers typically yield less per plant than photoperiods due to their smaller size and fixed timeline. However, you can run multiple auto cycles in the time it takes for one photo harvest.
When to Actually Harvest Based on What You See
Trichome color beats any calendar for determining harvest time.
Clear trichomes mean wait, cloudy trichomes indicate peak potency, and amber trichomes signal more mature, relaxing effects.
Those printed flowering times are rough guides at best. Every phenotype varies, and environmental factors like temperature and humidity shift your harvest window by weeks.
You don't need an expensive microscope either. A basic jeweler's loupe or even your phone's macro mode reveals trichome development clearly enough to time your chop.
Your Complete Growing Calendar Mapped Out
Example autoflower timeline: Start seeds March 1, see flowers by late March, and harvest mid-May. After drying and a basic cure, your jars are ready by late June.
Example fast-flip photo timeline: Start seeds on March 1 under 12/12 lighting, watch the flowers develop through April, and harvest in late May. Same late June jar date after processing.
Remember, these are ideal scenarios.
Apply that "add two weeks" buffer to any timeline you're planning around, especially for your first few grows.
Once harvested, proper storage becomes critical. Even perfectly grown cannabis can degrade quickly without the right conditions.
How Long From Seed to Harvest?
Realistically expect 10-12 weeks for autoflowers and 12-20+ weeks for photoperiods with standard veg time. Fast-flip photos can match auto timing at 11-13 weeks total.
Quick Answers About Growing Timelines
Do Photoperiods Grow Slower Than Autos?
Only if you extend the vegetative phase, fast-flip photos running 12/12 from seed can match or beat autoflower timing. The choice to grow more slowly yields larger plants and bigger yields.
Does 12/12 Make Autos Finish Faster?
No, 12/12 lighting reduces autoflower energy intake and stunts growth without changing the harvest date. Autos flower based on age, not light cycles.
How Much Time Should I Add to Breeder Timelines
Add two weeks minimum to any breeder estimate, then watch trichomes instead of counting days. Most "8-week" strains run 10-11 weeks under real conditions.
Growing Laws and Final Timeline Tips
Check your state and local laws before starting any grow - possession limits and cultivation rules vary dramatically.
Some states allow home growing while others prohibit it entirely. If you're looking for legal alternatives, hemp-derived THCa products offer a federally compliant option, thanks to the 2018 Farm Bill, in many states.
We're not a medical or wellness authority here at Mood. These timelines reflect community experience for educational purposes only.
Final wisdom from countless grows: trust what you see through a loupe over what's printed on a package.
Build buffer time into any growing plan, and remember that our ready-to-enjoy products offer timing certainty when your harvest runs long.
