Top 10 Strongest and Most Potent Autoflower Strains - 2021 UPDATE

Cannabis varieties Growing

Autoflowering strains are no-nonsense cannabis plants that are hardier and easier to grow than regular strains. The go-to for novice growers or busy schedules, you can enjoy the same high potency with less effort. Find out the top 10 autoflower strains loaded with high THC levels and potency here.

Strong and potent, the rise of High THC autoflowers

Autoflowering strains do exactly what they say, they flower automatically without laborious lighting prompts and training. Why is that better?

Well, they’re faster and easier to grow, and far more discreet thanks to their smaller size. If you’re short on time or new to growing, these hardy varieties are the perfect option.

You might think that this affects the quality and strength of the cannabis. While that may have been true in the past, it’s no longer the case. Today’s top-quality autoflowering seeds can be just as potent as their photoperiod cousins. No more sacrificing convenience for big and bold THC levels, these resilient strains provide extraordinary, resin-thick buds that are harvested in no time at all.

Top 10 Strongest High THC autoflower strains

  1. Gorilla Glue Auto – up to 26% THC
  2. Bruce Banner Auto – up to 25% THC
  3. Critical Purple Auto – up to 25% THC
  4. Girl Scout Cookies Auto – up to 22% THC
  5. Haze Auto – up to 22% THC
  6. Gelato Auto – up to 21% THC
  7. Green Crack Auto – up to 21% THC
  8. Zkittlez Auto – up to 20% THC
  9. Jack Widow Auto – up to 20% THC
  10. Critical Auto – up to 20% THC

1. Gorilla Glue Auto – Most potent 2021
High THC levels of up to 26%

Renowned for its super-charged THC levels which can reach up to 26%, Gorilla Glue produces a fine, award-winning buzz. Its potency comes through in the thick resiny buds that are so sticky and difficult to cut that it got its name, Gorilla Glue.

Growing

Gorilla Glue is an easy-grow strain with a short flowering time and fast harvest. Perfect for beginners, you can plant this autoflower strain indoors or outdoors, depending on your climate. Gorilla Glue prefers warm and dry Mediterranean-like conditions, but can cope with some variation and levels of humidity too. Indoor setups are easy to control thanks to Gorilla Glue’s compact trimmed height and versatility with training methods like SCROG. Just remember to buy a strong pair of scissors for harvest!

Smell, taste and effect

Gorilla Glue boasts a wonderful flavor profile of earth, coffee and rich fruits. There are layers of diesel thanks to the impressive THC levels. Due to its potency, this isn’t one for the uninitiated. It offers a very powerful euphoric blast that can lead to full-body relaxation. Its sedative qualities make it an ideal treatment for stress, anxiety and insomnia.

Gorilla Glue autoflowering feminized seeds Gorilla Glue autoflowering feminized seeds
Levels 26% THC / 1% CBD
Variety 50% Indica / 40% Sativa
Yield 350 to 550 grams/m²
Flowering time up to 56 days
Growersprofile Beginner

2. Bruce Banner Auto – Most potent 2020
High THC levels of up to 25%

Bruce Banner lives up to its Hulk-related name, providing THC levels of up to 25%. Just like the Hulk, it offers a potent hit of energy thanks to its Sativa-dominant genetics. You won’t find yourself “smashing” anything other than your own mind block, as this is a creative and motivating strain.

Growing

Bruce Banner is easy to grow as an autoflowering strain, with consistent and quick harvests. While fine for beginners, it does require space to grow. That makes it particularly suited to outdoor environments, where it can reach its yield potential. If you’re not fortunate to bask in warm conditions, you can utilize training and topping methods indoors to keep things under control. Bruce Banner is highly resistant to mold, mildew and pests.

Smell, taste and effect

Bruce Banner possesses an intriguing flavor profile that’s sweet and sharp, with a big diesel THC aroma. To taste, there’s plenty of rich, sweet berries and earthy undertones. Bruce Banner’s hybrid genetics soothe the body and mind, but the overall mental effects are more Sativa-like, with introspective and energetic effects. Creatives turn to Bruce Banner for its inspiring THC boost, while medicinal users praise its ability to combat chronic pain.

Bruce Banner autoflowering seeds Bruce Banner autoflowering seeds
Levels 25% THC / 0.1% CBD
Variety 30% Indica / 50% Sativa
Yield 250 to 600 grams/m²
Flowering time up to 56 days
Growersprofile Beginner

3. Critical Purple Auto – Most potent 2019
High THC levels of up to 25%

This potent, high-quality hybrid boasts impressive THC levels of up to 25%. It’s a high-quality plant that wears its Indica genetics strongly, offering compact growth and a big, relaxing high.

Growing

Critical Purple is an ideal beginners plant, due to its robust and forgiving profile. Entering the flowering phase quickly with no extra help, these autoflower seeds can be grown indoors, outdoors or in a greenhouse. You can keep things compact and utilize training methods like SCROG and SOG. What’s more, while Critical Purple thrives in warm, dry climates, it can handle more variation in temperature and rain than other strains – making it good for outdoor growth in temperate Europe.

Smell, taste and effect

Critical Purple holds the best flavor characteristics of Critical Mass and Big Bud, its two parent strains. You’ll get sweet skunky aromas and a floral highlight of rose petals and orange blossom. Due to its impressive THC levels, Critical Purple boasts a sudden and long-lasting high with euphoric and relaxing characteristics. Its soothing properties make it particularly good at combatting chronic pain and muscle spasms.

Critical Purple autoflowering seeds Critical Purple autoflowering seeds
Levels 25% THC / 0.7% CBD
Variety 60% Indica / 20% Sativa
Yield 150 to 350 grams/m²
Flowering time up to 70 days
Growersprofile Beginner

4. Girl Scout Cookies Auto – Most potent 2018
High THC levels of up to 22%

Girl Scout Cookies is one of the most exciting and popular strains right now. From its potent THC levels of up to 22% to its fresh and mouth-watering aroma, it’s little wonder Girl Scout Cookies has been dominating competitions and dispensary menus.

Growing

Girl Scout Cookies is an Indica-dominant strain that’s easy to grow, train and harvest. While warm California-like conditions are perfect for outdoor growing, we aren’t all blessed by such fine weather. If not, take things indoors. Girl Scout Cookies is a low maintenance plant that thrives in hydroponic conditions and responds excellently to training methods.

Smell, taste and effect

Girl Scout Cookies has a deceptively sweet aroma for such a potent plant. Like a good batch of baked cookies, you’ll get notes of chocolate, berry and mint alongside a skunky earthiness. The effects are widely renowned for their long-lasting euphoric effects. Perfect as an end-of-day smoke, the full-body relaxation is perfect for those treating stress and nausea.

Girl Scout Cookies autoflowering seeds Girl Scout Cookies autoflowering seeds
Levels 22% THC / 0.5% CBD
Variety 60% Indica / 20% Sativa
Yield 250 to 600 grams/m²
Flowering time up to 63 days
Growersprofile Beginner

5. Haze Auto – Most potent 2017
High THC levels of up to 22%

Haze is a classic of the Sativa world, made all the more user-friendly with this autoflower variation. Boasting an epic THC level of up to 21%, this strain was at the center of 1960s California and its incredible art scene.

Growing

Haze is a very easy to grow strain that works just about anywhere. Outdoor growers, however, must have warm and sunny Mediterranean or tropical conditions for the best success. Not blessed with plentiful hours of daily sunshine? Haze grows equally easily indoors or in greenhouses, with easily managed heights of around 100 cm. Haze is also fairly forgiving and resistant to mold and mildew, so you won’t have to spend too long tending to it.

Smell, taste and effect

Haze is a beautified classic when it comes to taste and effect. With a rich and earthy flavor profile with sweet and sharp citrus notes, it’s a legendary combo that has influenced countless hybrids. The high is renowned for its energizing and enlightening effects, making it among the most renowned high-energy options out there. The THC levels are powerful here, too, so don’t overdo it if you have a low tolerance.

Haze autoflowering feminized seeds Haze autoflowering feminized seeds
Levels 22% THC / 1.5% CBD
Variety 10% Indica / 70% Sativa
Yield 100 to 250 grams/m²
Flowering time up to 77 days
Growersprofile Beginner

6. Gelato Auto – Most potent 2016
High THC levels of up to 21%

Gelato is like any great dessert, moreish, sweet and guaranteed to please. With a perfect blend of Indica and Sativa elements, the strong THC content of some 21%+ has made it a mainstay of cannabis connoisseurs and menus worldwide.

Growing

Gelato autoflowers grow compact and fast, making them perfect for those short on space. Perfect for growers of any type, this strain is suited to indoor or outdoor cultivation and does just as well in greenhouses. While Gelato is relatively forgiving, it needs just the right nutrition to promote its glorious terpene profile. It doesn’t like humidity, so keep levels low. Outdoor growers need dry and warm conditions for healthy harvests.

Smell, taste and effect

Creamy, sweet and with just enough spice, Gelato is a crowd-pleaser. Its big berry sweetness blast is the perfect companion to its strong THC high. The effects of Gelato can be considered very potent. Big euphoric and relaxing effects come on quickly and are long-lasting. The excellent balance between calming and energizing makes it particularly adept at treating pain and insomnia.

Gelato autoflowering seeds Gelato autoflowering seeds
Levels 21% THC / 0.04% CBD
Variety 40% Indica / 40% Sativa
Yield 400 to 900 grams/m²
Flowering time up to 56 days
Growersprofile Beginner

7. Green Crack Auto
High THC levels of up to 21%

Green Crack is a turbo-charged plant that boasts strong THC levels that can reach up to 21%. While Sativa dominates this plant’s effects and aroma, it’s remarkably compact thanks to its autoflower genetics, offering a big blast for such a small package.

Growing

Green Crack can be grown indoors or outdoors, and by novices or experts alike. This strain prefers basking in warm Mediterranean heat and sunshine with low humidity. If you can’t facilitate this outdoors, she’ll grow excellently inside. Perfect for both hydroponic and soil setups, many have great success applying SCROG training methods. The addition of autoflowering Ruderalis has upped Green Crack’s pest and mold resistance.

Smell, taste and effect

Green Crack has a bold and tangy fruity flavor profile with layers of mango, citrus and spice. The strain is well-known for its rich, energizing effects that are long-lasting and buzzing. The potent THC content makes this a firm favorite as a daytime option and for the treatment of stress and anxiety symptoms.

Green Crack autoflowering seeds Green Crack autoflowering seeds
Levels 21% THC / 0.7% CBD
Variety 30% Indica / 50% Sativa
Yield 250 to 400 grams/m²
Flowering time up to 42 days
Growersprofile Beginner

8. Zkittlez auto
High THC levels of up to 20%

As colorful and vibrant as a bag of candy, Zkittlez is an irresistible and potent strain. An almost equal hybrid of Indica and Sativa varieties, it boasts huge THC levels of up to 20%.

Growing

Zkittlez is super easy to grow thanks to its autoflowering genetics. Resistant to mold, mildew and pests, it suits both indoor and outdoor growers of all experience levels. It does, however, prefer hot and sunny climates. This is easily mimicked indoors with a good light setup and training methods to promote richer buds. Zkittlez is a hungry plant, however, so be sure to give it plenty of nutrients.

Smell, taste and effect

Zkittlez is a sweet and fruity hybrid with a gorgeous aroma of grape and strawberry. Despite its mouth-watering sweetness, it boasts a considerably potent THC hit, making it a favorite for those in search of relaxation. The effects are calming and uplifting, while still remaining focused. Larger doses will lead to couch lock.

Zkittlez autoflowering seeds Zkittlez autoflowering seeds
Levels 20% THC / 0.3% CBD
Variety 40% Indica / 40% Sativa
Yield 100 to 300 grams/m²
Flowering time up to 56 days
Growersprofile Beginner

9. Jack Widow Auto
High THC levels of up to 20%

This impeccable clone of the legendary Jack Herer offers exceptional THC levels of up to 20%. Predominantly Sativa in origin, this delightful energizing high is matched by a solid CBD profile for added calming effects.

Growing

Jack Widow autoflowering seeds are easy to grow in most setups. Jack Widow does grow large, however, so adequate space is required. You can keep things compact and bushy through training methods and pruning techniques. If you have the outdoor space, Jack Widow loves basking in Mediterranean sunshine and warmth. Still, it’s robust and forgiving enough to cope with more variable temperate conditions, so long as the sun and warmth are there.

Smell, taste and effect

Jack Widow’s flavor profile is a classic blend of citrus and wood notes. Beneath this sweet lemon and pine is a dank and mossy, earthy aroma. Jack Widow is renowned for its potency, bringing big uplifting effects that energize and inspire. This big cerebral high is noted for clearing the mind and inspiring creative thoughts.

Big Jack Widow autoflowering feminized seeds Big Jack Widow autoflowering feminized seeds
Levels 20% THC / 1.5% CBD
Variety 30% Indica / 50% Sativa
Yield 60 to 250 grams/m²
Flowering time up to 77 days
Growersprofile Beginner

10. Critical Auto
High THC levels of up to 20%

Critical is a big, juicy strain that’s well-loved for its old-school feel and effects. The product of its Skunk and Big Bud origins, it boasts huge THC levels of up to 20%.

Growing

Critical autoflower seeds are perfect for beginners. These hardy and robust seeds grow in a wide range of climates and setups, from temperate outdoors to SOG interiors. Resistant to mold and mildew, you can keep things compact by utilizing training methods during growth. While this is a no-nonsense and relatively simple strain to grow, good nutrition and soil go a long way in yielding greater and more potent results.

Smell, taste and effect

Critical’s flavor profile is classically sweet with notes of citrus and berries. You’ll find herbal and earthy notes too to add complexity. The high is a luxurious blend of sedative and soothing effects with an uplifting euphoria. This is one for the end of a stressful day or for treating the symptoms of chronic muscle pain and anxiety.

Critical autoflowering feminized seeds Critical autoflowering feminized seeds
Levels 20% THC / 0.5% CBD
Variety 50% Indica / 30% Sativa
Yield 400 to 600 grams/m²
Flowering time up to 63 days
Growersprofile Beginner

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