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Fast Flowering Marijuana Seeds

Fast flowering seeds are photoperiod strains bred to finish in about 6 to 8 weeks of bloom, often a week or two sooner than standard strains. You keep full control over plant size and can still take clones, but you harvest sooner. That helps indoors on a tight schedule and outdoors where fall weather arrives early. Shipping is free over $200, and our germination guarantee covers every seed.

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Quick answerFast flowering seeds grow photoperiod plants that finish flowering roughly 6 to 8 weeks after the switch to 12 hours of darkness. Unlike autoflowers, they still need that light change to bloom, so you decide how big they get. Outdoors in northern states, many finish in mid to late September.

What are fast flowering seeds?

Every photoperiod strain has a flowering time written into its genetics, and most finish in 8 to 10 weeks. Fast flowering strains come from short-season parents, usually indica-heavy lines, or from crosses that borrow early-finishing genetics while staying photoperiod.

They sit between standard photoperiods and autoflowers. You get a quicker turnaround than standard strains, plus the freedom to veg as long as you like, train hard and keep mother plants, which autoflowers don't allow.

Fast flowering vs standard vs autoflower

TraitFast floweringStandard photoperiodAutoflower
Flowering time6-8 weeks8-10+ weeksStarts on its own, 8-12 weeks seed to harvest
Needs 12/12 to flowerYesYesNo
Control over sizeFullFullLimited
ClonesYesYesNot practical
Typical outdoor finish, northern USMid to late SeptemberEarly to mid OctoberDepends on planting date

How to grow fast flowering strains

  • Plan the calendar indoors. With 4 weeks of veg and 7 weeks of bloom, a run takes about 12 to 13 weeks from germination. Our harvest date calculator does the math for you.
  • Don't fall behind on feeding. The bloom phase is short, so move to flowering nutrients as soon as you flip and keep feeding steady from week 1.
  • Use the early finish outdoors. In the Pacific Northwest, Northeast and Upper Midwest, fall rain and first frost often arrive by early October. A late-September harvest dodges most of that risk.
  • Stay on top of humidity. Many fast strains are indica-leaning with dense buds, so keep humidity near 40-50% late in flower and give plants strong airflow.

Related seeds and tools

Autoflower SeedsEven faster from seed, no light change.Indica SeedsCompact genetics behind many fast strains.Outdoor SeedsClimate-matched picks for every region.Marijuana Seeds in MichiganGreat Lakes weather, where an early finish helps.

Fast flowering seeds FAQ

How fast do fast flowering seeds finish?

Most fast flowering strains finish 6 to 8 weeks after you switch to 12/12, compared with 8 to 10 weeks for many standard strains. Total time from seed depends on how long you veg. With a 4-week veg, expect about 12 to 13 weeks from germination to harvest.

Are fast flowering seeds the same as autoflowers?

No. Fast flowering strains are photoperiod plants and need 12 hours of uninterrupted darkness to bloom. Autoflowers flower on their own based on age. Fast flowering strains give you more control over size and allow cloning, while autos are usually quicker from seed to harvest.

Do fast flowering strains yield less?

Sometimes slightly less per plant, since buds have fewer weeks to fill out. But you can run more harvests per year, and outdoors you avoid the losses late-season mold or frost can cause. Indoors, a slightly longer veg makes up much of the difference.

When should I plant fast flowering seeds outdoors?

Plant after your last frost, once nights stay above about 50°F (10°C). In most northern states that means mid May to early June. The plant vegetates through early summer and starts flowering as nights lengthen in late July or August.

Are fast flowering strains good for beginners?

Yes. A shorter bloom means fewer weeks for problems like pests, mold or nutrient issues to build up. Quicker harvests also mean quicker feedback, so you learn faster. Many are indica-leaning and compact, which suits small tents.

Harvest before the weather turns

Pair a fast flowering strain with our outdoor planting guide to time your season from first sprout to final chop.

When to plant outdoors
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