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early flowering cannabis seeds

20 FASTEST Flowering Strains to Grow from Seed

Fastest Flowering Autoflower Strains

Sour Crack Auto

THE FASTEST autoflowering strain that Mephisto Genetics has ever grown, Sour Crack Auto finishes in only 7 weeks from seed (germination). Sour Crack Auto is made from Green Crack Auto and 24 Carat genetics. The short plants stay 20 to 28 inches tall, forming rock hard, resinous buds in quick time. A great strain for commercial quality Sea of Green autoflower grows. High potency nuggets tested near 20% THC.

Grow Time 7 weeks from seed
Strain Breeder Mephisto Genetics
Pack Size 1/3/7/18 seeds
Yield Indoors: 30–60 g/plant
Outdoors: 60+ g/plant

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+ Speed Auto

+ Speed Auto by Sweet Seeds are among the quickest finishing autoflower seeds to grow, being ready to harvest at just 7 weeks from germination. This strain is comprised of the breeder’s own Critical Mass and Speed Devil #2 Auto genetics, bred for yield and deep aromatic properties. + Speed Auto does well both indoors and outdoors. The plants grow 20 to 35 inches in height, producing harvests up to 150 grams each. Tastes sweet, fruity and cheesy.

Grow Time 7 weeks from seed
Strain Breeder Sweet Seeds
Pack Size 3/5/10/25/100 seeds
Yield Indoors: 350–500 g/m2
Outdoors: 30–150 g/plant

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Fast Bud #2 Auto

Fast Bud #2 improves upon Sweet Seeds’ Fast Bud line, a member of the Diesel family of cannabis. This award-winning sativa dominant autoflower strain is quick to mature at 7 to 8 weeks from seed. Only reaching 20 to 35 inches in height, the short plants are multi-branched and form a large number of bud sites, making it an easy strain to grow with very productive yields. Fast Bud #2 Auto has a sweet aroma, exotic taste, strong head high and powerful body stone. 15–20% THC.

Grow Time 7–8 weeks from seed
Strain Breeder Sweet Seeds
Pack Size 3/5/10 seeds
Yield Indoors: 350–500 g/m2
Outdoors: 20–70 g/plant

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Sweet Skunk Auto

Sweet Skunk Auto is one of Sweet Seeds’ best yielding and most resinous autoflower weed strains. Genetically, it’s a hybrid of Early Skunk and Critical Mass, backcrossed twice to Early Skunk. The plants grow rapidly and get 24 to 35 inches tall, finished at just 7½ weeks from germination. Its buds are dense and covered in trichomes. Intense skunk aromas with a sweet and spicy background. Physically relaxing with an uplifting head high. 16–20% THC.

Grow Time 7½ weeks from seed
Strain Breeder Sweet Seeds
Pack Size 3/5/10/25/100 seeds
Yield Indoors: 400–550 g/m2
Outdoors: 35–150 g/plant

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Alaskan Purple Auto

Alaskan Purple Auto by Seedsman, one of the best seed banks, is a 90% indica purple weed strain that produces good yields in short time. It finishes growing at 8 weeks from seed, with some phenotypes ready to harvest at week 7. They are easy growing, sizable plants for an autoflowering strain that mature one week later when grown outdoors. Ripe, fruity sweet flavors and 15–20% THC content.

Grow Time 7–8 weeks from seed
Strain Breeder Seedsman
Pack Size 1/3/5/10/100 seeds
Yield Indoors: 400–550 g/m2
Outdoors: 40–200 g/plant

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Crystal Candy XL Auto

Crystal Candy XL Auto is a large autoflowering marijuana strain, bred from tall phenotypes of Sweet Seeds’ Crystal Candy Auto line. This mostly sativa variety is suitable for both indoor and outdoor growing. The plants reach a height of 35 to 55 inches, ready for harvest at only 8 weeks from seed. Its buds are packed with trichomes and have a very fruity scent. 14–19% THC.

Time 8 weeks from seed
Strain Breeder Sweet Seeds
Pack Size 3/5 seeds
Yield Indoors: 425–650 g/m2
Outdoors: 60–300 g/plant

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Sweet Gelato Auto

Sweet Gelato Auto by Sweet Seeds is an autoflowering version of one of the most prestigious cannabis strains from the Bay Area—Gelato (Sunset Sherbet x Girl Scout Cookies “Thin Mint”)—crossed to Killer Kush Auto. The resulting plants offer generous yields in just 56 days from germination. Its dense buds are covered in large trichomes. The scent is earthy, sweet and fruity with hints of mint and citrus. 18–23% THC.

Grow Time 56 days from seed
Strain Breeder Sweet Seeds
Pack Size 3/5 seeds
Yield Indoors: 375–500 g/m2
Outdoors: 50–175 g/plant

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Sweet Cheese XL Auto

Sweet Cheese XL Auto is a fast and furious Cheese strain that offers greater size, yield and resin production than Sweet Seeds’ original Sweet Cheese Auto. This mostly sativa strain autoflower is ready to harvest at 8 weeks from seed, growing to a height of 30 to 55 inches. It has an intense, remarkably sweet, skunky scent and powerful yet relaxing high. 15–20% THC.

Grow Time 56 days from seed
Strain Breeder Sweet Seeds
Pack Size 3/5/25/100 seeds
Yield Indoors: 375–600 g/m2
Outdoors: 45–190 g/plant

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Purple Punch Auto

Purple Punch Auto is a fast, productive and flavorful autoflower variety sold by Barney’s Farm Seeds. A top performer indoors and out, this low-maintenance, mostly indica strain shows resistance to mold, mildew, mites and cold weather. The plants max out at 31 inches tall over their short lifecycle that takes between 50 to 60 days from seed. Its colorful, dense buds are rich in resin and terpenes with scents of sweet apple pie and cloves. Up to 18% THC.

Grow Time 50–60 days from seed
Strain Breeder Barney’s Farm Seeds
Pack Size 1/3/5/10 seeds
Yield Indoors: 350 g/m2
Outdoors: 400 g/plant

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Chocolate Skunk Auto

A “60 day wonder” strain being ready to cut 60 days from seed germination, Chocolate Skunk Auto by 00 Seeds is an autoflowering hybrid of Chocolate Skunk and ruderalis genetics. The plants grow large for an auto strain at over 40 inches tall. Chocolate Skunk Auto produces beautiful compact, crystal-covered buds that smell great. 17% THC.

Grow Time 60 days from seed
Strain Breeder 00 Seeds
Pack Size 3/5 seeds
Yield Indoors: 250–350 g/m2

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Fastest Flowering Photoperiod Strains

Gigabud

Gigabud is a Big Bud and Northern Lights hybrid that finishes flowering in a speedy 5 to 6 weeks. These thirsty, medium-sized plants grow vigorously in veg and flower, producing massive quantities of resinous, fruity buds. There is also an autoflowering Gigabud strain for sale.

Flowering Time 5–6 weeks
Strain Breeder G13 Labs
Pack Size 5 seeds
Yield 450+ g/m2

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Hash Plant

The famous Sensi Seeds Hash Plant indica originates from Afghani genetics bred in the Northwest United States that were brought to Sensi Seeds in Holland, where it was crossed to another Afghan variety—Northern Lights. Ready to harvest in as quick as 40 days from flowering, Hash Plant seeds grow fast, in a stout, thick manner. The buds are super dense, very sticky and ideal for making hash. A good choice for breeders.

Flowering Time 40–45 days
Strain Breeder Sensi Seeds
Pack Size 10 seeds
Yield 400–500 g/m2

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Green Poison Fast

Green Poison Fast by Sweet Seeds is a top quality weed strain which forms super frosty and tight buds. This unique feminized seed strain was made by breeding out the ruderalis gene present in the original autoflowering Green Poison to create a remarkable, high yielding photoperiod variety. 70% indica genetics are responsible for its fruity, heavy and dank marijuana buds.

Flowering Time 6 weeks
Strain Breeder Sweet Seeds
Pack Size 3/5/10/25/100 seeds
Yield Indoors: 500–600 g/m2
Outdoors: 500–700 g/plant

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Passion #1

Passion #1 is an outdoor indica strain from the seventies in California, which made its way over to Holland during the eighties. This stable, easy to grow regular seed strain gets huge both outdoors and indoors, finishing its flowering cycle in a mere 6 weeks of bloom time. Passion #1’s citrus-like buds are long, dense and full of resin. 18.6% THC content.

Flowering Time 6 weeks
Strain Breeder Dutch Passion
Pack Size 10 seeds
Yield 250–750 g/plant

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Tropicanna Poison F1 Fast

Tropicanna Poison F1 Fast by Sweet Seeds is an excellent fast flowering strain bred for speed and potency. It was created using an elite Tropicanna Cookies clone crossed to a red flower phenotype and Red Poison Auto. Roughly 80% of the resulting plants get red bud coloring. This very productive variety is finished at only 6 to 7 weeks of bloom. The buds are dense, extremely resinous and have intensely sweet scents and flavors. 16–24% THC.

Flowering Time 42–49 days
Strain Breeder Sweet Seeds
Pack Size 3/5 seeds
Yield Indoors: 450–600 g/m2
Outdoors: 400–650 g/plant

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Big Nugs Fast

As the name suggests, Big Nugs Fast grows big nugs—fast. It’s a photoperiod hybrid that’s ready to harvest in only 6 to 7 weeks flowering time. This high yield weed strain is bred from Big Bud / Critical Mass (Afghani x Skunk) crossed to Seedsman’s fast finishing male. Similar to Big Bud, Big Nugs Fast grows thick heavy buds, which may need to be propped up during flowering. Yields are high—expect dense, pine cone-shaped buds with fruity, hashy qualities.

Flowering Time 6–7 weeks
Strain Breeder Seedsman
Pack Size 1/3/5/10/100 seeds
Yield 450–550 g/m2

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C99 x Blueberry Fast

C99 x Blueberry Fast is a rapid flowering, mostly sativa weed strain that’s ready to harvest in just 45 days from the start of bloom cycle. The infamous C99 strain is crossed to Blueberry and then bred with Seedsman’s fast parent, resulting in sativa dominant seeds that finish quick. Its Thai genetics present help C99 x Blueberry Fast grow big during flowering, so expect some stretching. High yields of thick, potent marijuana buds.

Flowering Time 6–7 weeks
Strain Breeder Seedsman
Pack Size 1/3/5/10/100 seeds
Yield 350–450 g/m2

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Gorilla Girl F1 Fast

Gorilla Girl F1 Fast by Sweet Seeds is an extra-fast version of Gorilla Girl featuring extreme potency and production. The sativa dominant plants are ready to harvest after just 7 weeks of flowering. Its buds are known for their high resin content, with calyxes completely covered in frosty trichomes. The aroma and taste are sweet and fruity with earthy, woody notes. Strong effects—up to 24% THC.

Flowering Time 49 days
Strain Breeder Sweet Seeds
Pack Size 3/5 seeds
Yield Indoors: 400–500 g/m2
Outdoors: 350–600 g/plant

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Pineapple Express #2

Pineapple Express #2 is a faster flowering, higher yielding version of G13 Lab’s original Pineapple Express. A favorite weed strain among growers in humid climates, Pineapple Express #2 grows huge outdoors and has high resistance to mold and moisture. Its buds are large, fruity and full of trichomes.

Flowering Time 45–50 days
Strain Breeder G13 Labs
Pack Size 5 seeds
Yield Indoors: 700 g/m2
Outdoors: 900–1300 g/m2

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Pakistan Valley

Originating from the Hindu Kush mountains, Pakistan Valley by WOS is a landrace pure indica cannabis strain that grows quick, finishing its flowering phase in just 45 to 55 days. A compact, vigorous grower, especially suited towards dry climates where its buds bulk up dense and resinous. Super sticky and potent—over 20% THC. For sale as both regular and feminized seeds.

Flowering Time 45–55 days
Strain Breeder World of Seeds
Pack Size 10 seeds
Yield Indoors: 400 g/m2
Outdoors: 700 g/m2

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11 thoughts on “20 FASTEST Flowering Strains to Grow from Seed”

Consider Bubba’s gift from Humboldt seeds. 6 weeks flowering and nice purple hues

Im growing Bubbas Gift this season and it hasnt started to show sex yet. Just hope its done before the 1st week of October. Weather in the North East US can get really crappy in Oct . Anybody else out there have experience with this strain?

Speedy Chile fast by royal Queen is the fastest I’ve heard of. It’s finished in 56 days from germination and only needs 14 days veg. 16% Thc. Fem photo 80-100cm tall and 500+ grams per m2 indoor. Critical poison fast should be on the list too. Finished in 40-45 days 18% thc Fem photo 500+ grams per m2 indoor.

HI bro, how many plants per m2 can u grow with these??

Wow. This is a real treat for both the consumers and the farmers. Personally, I like Green-O-Matic Auto. It sorts of suits me. Thanks a lot for sharing.

Pineapple Express #2 from G13 Labs all day on my 3rd run with this strain and I have more chasing it

Bro, i have a special pheno of her, been runnin her for like 4 years now.. Its amazing what she does in just 50 days… I like to run an extra 10 days though…

got some free seeds from just cannabis seeds and so I thought I would throw a few of them in the dirt, only one was fem and a hearty little sativa that I topped 3 times for max yield and about 45 days in it looked like I was well on my way to getting 1/2 lb off of her when the buds fattened up in coming weeks considering I had about 4 more weeks before harvest, but just for fun I thought I would check the trichomes at a time I felt was early, and WTF. I’m sitting on 15 to 40% amber and no clear trichomes, in 45 days, on a pure sativa!! Well my yield wont be as big but its an early surprise. Wish I would have cloned her,

Just leave a couple small buds and regenerate growth after your harvest.

Lemon Pie Auto takes 3 months/12 weeks seed to buds

Both autoflowering seeds and photoperiod strains. The fastest flowering cannabis strains to grow from seed to harvest. Ordered by quickest start to finish

12-12 From Seed – Flowering Plants Early

The term “12-12” means you’re giving your cannabis plants 12 hours of darkness, and 12 hours of light every day. “12-12 from seed” mean you’re giving a cannabis plant a 12-12 light schedule from a very young age to force it to flower early (make buds) while staying small.

Cannabis plant growing with one main cola after being switched to 12/12 at around 3.5 weeks old from seed

Some growers are attracted to the idea of 12-12 from seed, because it means that harvest will come sooner. How long does it take to grow a plant from seed to harvest?

But does the 12-12 from seed technique work to give you a faster harvest, and if so, what are the results?

I have changed cannabis plants over to the flowering stage from seed, but no matter what the light schedule, plants don’t start flowering (making buds) until they are about 3 weeks old. Initiating a 12-12 light schedule at 3 weeks old from seed is as early as I’d recommend for this technique, if you choose to use it.

“12-12 From Seed” is a misnomer if you’re trying to force your cannabis to flower early – 3 weeks from seed is the earliest time a plant can start flowering after the switch to 12-12

Make sure to let your young marijuana plants get a minimum 2-3 weeks in the vegetative stage before changing them over to flowering. Your plants will be healthier and will start flowering at the same time as if you started 12-12 from when they first sprout.

Giving a 12-12 shedule when a cannabis plant is younger than that will not work to make the cannabis start flowering – a cannabis plant will only grow vegetatively for the first few weeks of life, and giving them less light will only cause them to grow more slowly.

Some strains of cannabis will naturally start flowering after about 3 weeks, and you don’t need to do anything with light schedules to cause that to happen. These strains are known as “autoflowering” or “Ruderalis” strains.

Many Growers Who Want To Force Cannabis Plants to Flower at a Young Age May Be Interested in Auto-Flowering Strains – No Need for 12-12 and Often Much Better Yields!

Keep marijuana plants small by growing them in a smaller container

I have grown a few plants from seed to harvest just in a solo cup container. I was able to do this by flowering a plant from a young age – giving the plant 12-12 lighting when it was only 3 weeks old (pictured here).

These solo cup plants were able to survive their entire lives in a small container. I wouldn’t recommend a solo cup because they tip over easily, and plants are prone to nutrient and root problems once the flowering stage begins (the root space is just way too small, even when doing 12-12 from seed or using an auto-flowering stage).

But it’s possible.

The downsides… When your cannabis is kept in a too-small container, you will notice that you have to water your plant much more often than if you kept your plant in a big pot. As time goes on, plants are also more likely to suffer from nutrient problems and root problems because the roots aren’t being give enough room to spread out. When plants become root-bound this way, there’s not much you can do about this besides transplanting your plants into a bigger container.

While I wouldn’t recommend 12-12 from seed, and no longer ever use this technique myself, there are growers who are going to do it anyway.

For those growers who still want to use 12-12 from seed despite the warnings here…

Smaller pots tend to keep plants smaller, but also need to be watered more often

If you are set on keeping potted cannabis plants in small containers for their whole lives, the smallest container you should try is a 1-gallon or 2-gallon container, like the pots pictured here.

Keeping plants in tiny containers may be important when growing in a very space-limited grow space, such as growing in a space bucket for stealth reasons.

There are powerful cannabis growth control techniques that will also allow you to grow high-producing plants, while keeping them short.

This marijuana plant was grown in a humble solo cup and flowered directly from seed (she was exposed to 12-12 light right in the beginnint)But like this extreme girl to the right (less than a foot tall and grown under CFLs), I’ve experimented starting the plants on 12/12 from seed to keep plants REALLY small.

When forcing your cannabis to flower early, plants will stay small and spend almost all their energy on producing flowers/buds on what few stems they have, instead of growing tall or making more colas/nodes.

Some people say that cannabis that is forced to flower too early will not make any buds, but that’s not true. The plant pictured here produced 0.75 ounces of bud after drying. So while 12-12 from seed may not be optimal, it does work.

The problems I’ve had with forcing cannabis to flower early is that since the plant is much smaller, you get smaller yields, but you’re still basically spending about the same amount of time to grow the plant as if you’d grown it bigger.

Compared to 12-12 from seed, growing an auto-flowering strain will generally give you bigger yields for the time, and will be less trouble

With such small plants, you don’t have the time to train your plant, which gives you much greater control over the final shape and size of your plant, improving yields without adding much time.

The other disadvantage to overly small plants is their inability to recover well from problems: you have fewer leaves as a ‘buffer’ so the plant can’t bounce back when something goes wrong such as a pest attack. In a too-small container, as roots get more root-bound, cannabis plants have a harder time using nutrients efficiently, and may start showing nutrient problems.

Growing extremely tiny marijuana plants is fun, but honestly you’ll get the biggest yields by instead investing a little more time in the vegetative stage to train your plant to grow into the exact shape you want. Or just grow an auto-flowering strain.

Auto-Flowering Strains – A better way to force plants to flower early

Plant Training Techniques – Make your plants grow how you want

Learn About Grow Lights – Which is best for your setup?

Learn what it means to give your plants "12-12 from seed" to force them to start making buds early.