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Growing cannabis can be difficult, whether you’re dealing with long flowering times, complex light schedules, or plants that grow too tall indoors. Autoflower seeds make it easier with shorter grow cycles, smaller sizes, and consistent results that do not require special lighting.

We’ve gathered the best autoflower strains, chosen for their THC strength, easy growing, great flavors, and solid yields indoors or outdoors.

Green Crack Autoflower is at the top due to its quick 7-8 week flowering time and beginner-friendliness, making it one of the best autos for fast harvests overall.

From high-THC powerhouses like Mystic Gorilla to sweet indoor favorites like Green Gelato Auto, heavy yielders like Critical Mass Auto, and fruity outdoor stars like Pineapple OG Auto, there’s something for every grower.

Best Autoflower Seed Banks

• Seed Supreme – Best feminized autoflower seeds
• Homegrown Cannabis Co. – Best autoflower seeds for beginners
• Herbies Seeds – Best indica autoflower seeds

First Look: Best Autoflower Seeds

1. Green Crack Autoflower – Best Overall Autoflower Seeds

Pros:

• Fast flowering time up to 7-8 weeks
• High THC levels of around 20%
• Beginner-friendly and resilient
• Compact size for indoor setups
• Free bonus seeds with qualifying orders

Cons:

• Some grow reports mention stunted starts

Green Crack Autoflower reaches up to 20% THC, making it one of the more powerful autoflowering strains. The buds are crystal-coated and packed with resin, offering excellent density for extractions. This strain is strong and suitable for beginners. Because of its autoflowering genetics, it does not require light schedule changes, and its compact size makes it ideal for small grow spaces.

Sweet mango and citrus flavors are balanced with earthy undertones and hints of peppery spice. The aroma is fruity but pungent, with a classic old-school skunk flavor. Green Crack Autoflower needs about 10 to 12 weeks to grow from seed to harvest. The flowering stage itself usually lasts for 7 to 8 weeks.

Indoor setups can deliver around 17-21 oz/m², while outdoor plants yield about 11 oz each, depending on climate and conditions. Green Crack shows up often in vape cartridges and disposables from brands like Tommy Chong. Tommy Chong’s Green Crack CO₂ Cartridge delivers an energizing high with about 17% THC.

The flavor is sweet and fruity with earthy undertones and it’s great for daytime use. It boosts energy, focus, and talkativeness, though some users may experience dry mouth or mild anxiety.

Why Buy From Seed Supreme 

SeedSupreme is the #1 U.S. seed bank, trusted by growers nationwide for its wide variety, discreet shipping, and germination guarantee. Orders over $50 include 4 free seeds, with rewards scaling up to 10 free seeds on $200+ orders. Regular promotions, bundle deals, and loyalty rewards make it one of the best places to buy the best autoflower seeds online.

>>Check the best prices for Green Crack Autoflower at SeedSupreme

2. Mystic Gorilla Autoflower – Best for Resin Production

Pros:

• Up to 26% THC, among the strongest autos
• Medium height, easy for tents or outdoors
• Big yields of dense, resinous buds
• Fast 6-8 week seed-to-harvest time
• Bold citrus-diesel-skunk aroma

Cons:

• Cycle runs a bit longer than some autos

Mystic Gorilla Autoflower is very strong, with THC levels up to 26%. The buds are thick and covered in crystals, making it one of the most powerful strains for growers. This strain is easy for beginners. It can handle stress, topping, and training. The only issue is that heavy buds can bend the branches, so a little support may be needed.

The flavor is strong and bold, with notes of diesel and skunk, as well as citrus and kush. It has a sharp taste but feels layered and smooth. The plants grow fast and are usually ready in 6 to 8 weeks. When grown indoors with strong lights, they can be ready even earlier.

Mystic Gorilla Autoflower is known for producing large harvests. The buds develop quickly and fully in both indoor and outdoor setups. Under ideal conditions, yields are typically 50 to 120 grams (1.8 to 4 ounces) per plant indoors and 100 to 200 grams (3.5 to 7 ounces) per plant outdoors with plenty of sunlight.

If you want to try Gorilla Glue strain. You can try Exhale Wellness’ Gorilla Glue Delta-8 Vape Cartridge delivers 900mg of Delta-8 THC with a powerful, smooth hit. The flavor combines citrus, lemon, chocolate, and coffee notes, giving you a balanced mix of earthy and sweet.

This cart is durable and long-lasting. It’s discreet, lab-tested, and additive-free, making it a safe choice for fans of the original Gorilla Glue strain.

Why Buy From Homegrown Cannabis Co.  

Homegrown works with Atlas Seed to create special strains like Mystic Gorilla, with stable genetics and high quality. They ship discreetly across the U.S., give grower support, and share free guides and videos. Buyers also get bundle deals on the best outdoor autoflower seeds and special strains that you won’t find anywhere else.

>>Check the best price for Mystic Gorilla Autoflower Seeds at Homegrown Cannabis Co.

3. Bruce Banner #3 Auto – Best for Hulk-Level Potency

Pros

• Sky-high THC levels up to 26%
• Rapid 60–70 day seed-to-harvest time
• Heavy indoor yields of 1.8–2.1 oz/ft² and outdoor harvests up to 26–30 oz/plant
• Balanced 50% Sativa / 35% Indica profile for creative yet relaxing effects
• Beginner-friendly, resilient genetics

Cons 

• Strong aroma may require extra odor control

Bruce Banner #3 Auto is a true powerhouse, regularly testing at 26% THC. The high starts with a soaring Sativa rush, euphoric, energetic, and intensely creative, before settling into a calm, Indica-driven finish that lingers for hours.

Thanks to 15% Ruderalis genetics, this strain is hardy and easy to manage. It thrives indoors or outdoors, forgiving beginner mistakes while rewarding attentive growers with exceptional yields.

You can expect a bold mix of sweet Kush, earth, and diesel notes layered with subtle fruitiness from the best sativa autoflower seeds. The aroma is pungent and unmistakable, so a quality carbon filter is recommended for stealth grows.

Seed to harvest takes roughly 60–70 days, making it one of the faster high-THC autos on the market. Indoors, growers can expect around 1.8–2.1 oz/ft² from this best fast growing autoflower strain. Outdoors, plants average 26–30 oz each when given ample sun and low humidity.

The initial Sativa kick sparks creativity and focus, perfect for daytime inspiration, while the Indica side melts away tension. You should start slow; a single puff can feel like a “Hulk smash” of euphoria.

Why Buy From Herbies Seeds 

Herbies Head Shop offers discreet worldwide shipping, extended lineup of 1,500+ strains, multiple payment options, and a germination guarantee. Orders often include free bonus seeds, making it an excellent source for this top-tier autoflower. You also get seeds that are guaranteed to sprout.

>>Check the best price for Bruce Banner #3Herbies Head Shop

4. Green Gelato Auto – Best for Indoor Growing

Pros:

• Very high THC for an autoflower (up to 24%)
• Compact plants (2-4 feet indoors, 3-4 feet outdoors)
• Grow quickly and are usually ready in 9 to 10 weeks from sprout.
• Candy-sweet, fruity, and earthy terpene profile
• Easy to grow, even for beginners

Cons:

• Strong aroma during flowering makes it less stealthy

Green Gelato Auto is very strong for an autoflower, with THC levels up to 24%. The buds are covered in crystals and resin, almost like regular photoperiod strains.

This strain is easy to grow and has stable genetics that provide consistent results for both beginners and experienced growers. The plants usually stay small, though some may stretch, so training indoors can be helpful.

The taste is sweet and fruity, similar to Gelato. It carries candy and sherbet flavors, with touches of Thin Mint Cookies and a light earthy note. It grows quickly and is typically ready in 9 to 10 weeks from seed. Most plants are ready to harvest in about 70 days, though a few may take longer.

When grown indoors, it can yield approximately 13 to 16 ounces per square meter. Outdoor growers typically see 3 to 6 ounces per plant. The harvest may not be the largest, but the resin-covered buds and high quality make it worthwhile.

Green Gelato often appears in vape cartridges under names like Berry Gelato from Exhale Wellness. This cart blends 200mg of THCa and 500mg of Delta-8 THC. The flavor has creamy berry milkshake notes with a gassy, funky aftertaste.

It’s a hybrid with relaxing, euphoric effects, great for winding down. Third-party tested, additive-free, and built for smooth flavor with a universal 510-thread battery.

Why Buy From Royal Queen Seeds

Royal Queen Seeds is a European seed company known for its award-winning genetics, commitment to sustainability, and stealth shipping to the United States.

They run rotating promotions with discounts ranging from 20 to 30% off select strains and accessories. Customers also have access to the Growers Club, which offers loyalty points, exclusive sales, and educational guides on the best autoflower seeds for outdoors.

>>Check the best price for Green Gelato Auto at RQS

5. Critical Mass Autoflower Seeds – Best for High Yields

Pros:

• Easy to grow, good for beginners
• Small plants under 3 ft, perfect for indoor grows
• High yields up to 455 g/m² indoors, 5-15 oz per plant outdoors
• Grows from seed to harvest in about 10 to 14 weeks.
• Smells skunky, earthy, and sweet with citrus notes

Cons:

• Dense buds can get bud rot if airflow is bad

Critical Mass Auto marijuna seeds contain about 22% THC along with some CBD. The strength is enough to satisfy heavy users, yet it remains manageable for casual consumers.

This strain is very easy to grow. Its autoflowering genetics mean there is no need to change light cycles. It also works well in small tents or in Sea of Green setups.

Critical Mass autoflower seeds produce earthy, herbal, and skunky flavors with a touch of citrus and spice. The aroma is classic and old-school, with sweet undertones that balance the profile.

It usually takes 10-14 weeks to mature from seed. Indoor plants are typically ready to harvest sooner, whereas outdoor plants may take the entire cycle.

Critical Mass Auto weed seeds are known for producing large harvests. Indoors, growers can expect around 455 grams per square meter. When cultivated outdoors, most plants yield between 5 and 15 ounces each, depending on the climate and growing conditions.

Critical Mass Autoflower mixes are not easy to find in gummies or vapes, but some products give a similar heavy, relaxing effect. Medterra’s Max Relief Full Spectrum CBD Gummies are one example.Each gummy contains 25mg of CBD and 2mg of THC, with a simple citrus flavor.

They are often used for calming down, stress relief, or relaxing after a long day. The gummies are vegan, made with clean ingredients, and lab-tested to ensure they are safe and reliable.

Why Buy From ILGM

ILGM is considered one of the most trusted seed banks in the United States. The company has sold over 30 million seeds to more than 700,000 growers. 

Every order comes with a germination guarantee, free shipping within 2 to 5 days, and discreet packaging. With an active grow forum and a dedicated support team, ILGM makes the process easy for both beginners and experienced growers.

>>Check the best price for Critical Mass Autoflower Seeds at ILGM

6. Pineapple OG Auto – Best for Outdoor Growing

Pros:

• Cross of Pineapple Kush, Pineapple Muffin Auto, and Emerald Fire OG Auto
• Very strong (24-26% THC, almost no CBD)
• Tropical smell and taste: pineapple, mango, guava
• Big, resin-covered buds (great for hash)
• High yields: up to 600 g/m² indoors, 200-450 g per plant outdoors

Cons:

• Smell is very strong (not good for stealth)

Pineapple OG Auto is very strong, testing between 24-26% THC with almost no CBD. It matches the strength of many photoperiod strains, making it one of the most powerful fruity autos.

This strain can grow in any setup but performs best indoors, where the yields are highest. The plants reach a medium height and are usually ready in 8 to 10 weeks. They need only simple care, and resin production is so heavy that even the leaves and stems become coated.

The flavor is tropical and sweet, with clear notes of pineapple, mango, and guava. It’s one of Seedsman’s most flavorful autos, loved for its fruity taste.

It takes 65-75 days from seed to harvest, with an average of 6 weeks in flower. When conditions are stable, indoor grows tend to produce at the faster end of the spectrum.

Indoors, Pineapple OG Auto can produce up to 600 grams per square meter, which is considered very high for an autoflower. When grown outdoors, the harvest usually ranges between 200 and 450 grams per plant, depending on the climate.

Pineapple OG often shows up in carts and disposables under Pineapple Express. Exhale Wellness’ Delta-8 Disposable Vape Pen delivers tropical pineapple and citrus flavors with subtle cedar notes, blending Trainwreck and Hawaiian genetics.

This all-in-one vape is smooth, portable, and easy for beginners to use. It may provide uplifting euphoria, improved focus, and relaxation in a discreet rechargeable device. Each pen typically offers around 200 to 300 puffs.

Why Buy From Seedsman?

Seedsman has one of the largest global seed selections, plus independent germination testing for quality control. They offer 10% off for first-time buyers and often run seasonal promos up to 30% off. Customers also enjoy loyalty points, freebies with orders, and secure U.S. warehouse shipping for fast delivery.

>>Check the best price for Pineapple OG Auto at Seedsman

What Are Autoflower Seeds?

Autoflower seeds are cannabis seeds bred to begin flowering based on age rather than changes in light exposure.

Unlike traditional photoperiod plants that need a strict shift from long days to short days to trigger flowering, best yield autoflower seeds automatically transition from the vegetative stage to bloom on their own, usually after just 3–4 weeks of growth.

This trait comes from their Cannabis ruderalis genetics, a hardy subspecies adapted to the short summers of northern climates.

Understanding Autoflowering

The defining feature of an autoflower plant is its built-in timer. From the moment the seed germinates, the plant starts counting down to flowering, no matter how many hours of light it receives.

Growers typically keep lights on for 18–24 hours a day throughout the entire cycle, which lets the plant photosynthesize continuously for faster growth.

Because the light schedule never needs to change, indoor growers save time and avoid the stress of carefully timed lighting setups.

Advantages of Autoflower Seeds

Autoflower seeds appeal to many growers for their speed. Most strains finish in 8–10 weeks from seed to harvest, allowing multiple crops per year. They stay shorter and bushier, making them easy to grow in small spaces or discreet outdoor spots.

Since flowering isn’t tied to daylight hours, plants can thrive indoors or outdoors at almost any time of year. Their ruderalis heritage makes them naturally tough, with good resistance to pests, diseases, and cooler temperatures.

>>Check the best prices for Green Crack Autoflower at SeedSupreme

Types of Autoflower Seeds to Consider

When you’re choosing the best autoflower seeds, it helps to understand the main categories. Each type offers distinct growth patterns, effects, and ideal growing conditions.

Feminized Autoflower Seeds

Feminized autoflowers are bred to produce only female plants, the ones that grow resin-rich buds. Because male plants don’t form usable flowers, feminized seeds save you from having to identify and remove males.

They’re perfect if you want to maximize yields in a small space or prefer a set-and-forget grow with minimal maintenance.

Indica Autoflower Seeds

Indica-dominant autoflowers tend to stay compact, with dense buds and a shorter flowering period. Their effects are often calming, making them popular for evening use or for those seeking relief from stress and muscle tension.

These strains are well suited to indoor grows or discreet outdoor spots where height control is important.

Sativa Autoflower Seeds

Sativa autoflowers grow a bit taller and take slightly longer to finish, but they deliver an energetic, uplifting high.

Their lighter, airy buds are great for daytime use or creative pursuits. Growers with enough vertical space and those who don’t mind a few extra days to harvest, often choose sativa-dominant autos for their stimulating effects.

Hybrid Autoflower Seeds

Hybrid autoflowers combine traits from both indica and sativa genetics, offering a balance of growth habits and effects. They can be tailored toward relaxation, stimulation, or a mix of both, depending on the strain.

Hybrids are ideal if you’re looking for versatile plants that adapt well to different climates and deliver a well-rounded experience.

Choosing the Right Autoflower Seeds

Picking the right autoflower seeds sets the tone for your entire grow. A little research in the start can save you time and frustration later.

Choosing a Seed Bank

Start with a trusted seed bank that guarantees discreet shipping, responsive customer service, and clear strain descriptions.

Look for sellers with consistent reviews and transparent germination policies so you know your investment is protected.

Evaluating Genetics

Genetics dictate everything from yield and potency to flavor and resilience. Decide whether you want a sativa-leaning buzz, a relaxing indica, or a balanced hybrid. Pay attention to THC and CBD levels, flowering times, and any traits like disease resistance that suit your climate.

Cultivation

Match the strain to your setup. Compact plants thrive in small indoor tents, while vigorous strains need more vertical space. If you’re growing outdoors, check that the variety can handle your region’s temperature swings and daylight hours.

Effects

Think about your desired experience before buying. Uplifting strains work well for daytime use, while relaxing ones are better for evening sessions. Read user reviews and breeder notes for clues about aroma, taste, and overall vibe.

>>Check the best prices for Green Crack Autoflower at SeedSupreme

How to Germinate and Grow Autoflower Seeds

Autoflowers are famously beginner-friendly, but a solid start and steady care make a huge difference.

Germination Techniques

Use a simple method like the damp paper towel in a warm, dark place or plant directly into a light, airy starter mix. Keep temperatures steady around 22–25 °C and never let the medium dry out.

Vegetative and Flowering Periods

Unlike photoperiod plants, autoflowers shift from veg to flower automatically, usually within 3–4 weeks. Plan your light schedule accordingly; 18–20 hours of light daily is ideal from seed to harvest.

Feeding

These compact plants prefer lighter nutrient doses, especially early on. Introduce bloom nutrients as soon as pistils appear and avoid heavy nitrogen once flowering starts.

Pests

Keep humidity in check, maintain good airflow, and inspect leaves often for mites, aphids, or fungus gnats. Quick action with organic sprays or beneficial insects keeps infestations from spreading.

Best Autoflower Seeds: FAQs

Here, we answer a few frequently asked questions about the best autoflower seeds.

What Is the Most Potent Autoflower?

Bruce Banner is widely considered one of the strongest autoflowering strains available, often testing at 25–26 % THC.

It delivers an intense, fast-acting high that blends a euphoric cerebral rush with a long-lasting body relaxation, making it a favorite for seasoned growers seeking top-shelf potency.

Who Has the Fastest Autoflower Seeds?

Seed Supreme consistently lists some of the quickest-finishing autoflower varieties, including strains that can be ready for harvest in as little as seven to eight weeks from germination.

This best autoflower seed bank in the United States has a catalog of 350+ strains highlighting exact flowering times so you can plan an ultra-fast grow without sacrificing quality.

Should I Buy Feminized or Autoflower Seeds?

If your goal is an easy, light-cycle-independent grow, autoflower seeds are the clear choice because they start flowering on their own.

Feminized photoperiod seeds give you more control over plant size and timing, but they require a strict light schedule and a longer overall grow period.

What Is the Downside to Autoflowering Seeds?

Autoflowers generally yield slightly less than photoperiod plants and allow limited time to correct mistakes, once flowering begins, there’s no way to extend the vegetative stage for recovery or training. Their compact size can also make cloning difficult, so each harvest usually starts from seed.

Are There Any 45-Day Autoflower Seeds I Can Buy?

Yes. Several breeders offer ultra-fast strains that finish in about 45 days from germination, including select hybrids featured at Seed Supreme and other reputable banks. These best 45 day autoflower seeds are ideal for growers who need rapid harvests or who face short outdoor seasons.

Best Autoflower Seeds: Final Thoughts

In the end, choosing the best autoflower seeds comes down to matching genetics with your growing style and goals.

After exploring potency, speed, and ease of cultivation, Green Crack stands out as our top pick for its high THC levels of 20%, fast-flowering period of 7-8 weeks and high yields.

While Seed Supreme stands as our top option for buying the best autoflower cannabis seeds due to their wide and diverse range of autoflower options, all the other seed sellers on our list are equally impressive and definitely worth your attention.

Whichever choice you make, we wish you well on your cultivation journey. Happy growing!