Strongest Autoflower Strains

Autoflowering cannabis strains have improved dramatically over the years, and they’re now more potent than ever. They are popular among growers for their small stature. Plus, there’s the fact that they don’t depend on the perfect amounts of changing light and darkness to start flowering. They also have shorter life spans.

If you’re planning to grow autoflowers, the best autoflowers for indoor growing, as well as the strongest outdoor autoflower cannabis strains, are well worth considering. The let growers enjoy all the benefits of an autoflower without sacrificing THC levels.  

What are Autoflowers

Autoflowering strains begin flowering at a certain age, rather than responding to the changing seasons (or, more specifically, the changing light). Photoperiod plants, on the other hand, go from their vegetative stage to the flowering stage only once the hours of daylight (whether that is artificial light or natural sunlight) begin to lessen below a certain point, and the hours of uninterrupted darkness have increased to a certain point.

Autoflowers generally have a shorter life cycle than other types of cannabis. Shorter life cycles can be handy for people who have a shorter grow season, such as in colder climates. It can also be useful for those with longer grow seasons that would like to enjoy two harvests during the warmer months. This can only be done with autoflowers since most photoperiod plants will not be ready in mid-summer.

Want to grow strong autoflowering strains? Download my free Grow Bible to learn how!

Autoflowers are also popular for their small size. It makes it easier to grow indoors and less of a hassle than larger cannabis plants. Indoor growers don’t need to prune or train them like they would larger plants, and both indoor and outdoor growers will find that autoflowers are easier to grow discreetly.

Autoflowers also tend to be quite resistant to pests, which adds a layer of ease to those who want to grow these hardy plants. The same goes for resistance to difficult weather conditions.

Autoflowers are a combination of the Cannabis ruderalis plant with either Cannabis indica or cannabis sativa. At first, it had a bad reputation because it was not as high in THC as other weed options. Nowadays, however, autoflower strains have vastly improved. Gone are the days when autoflowers meant weak marijuana plants!

How Do Marijuana Breeders Measure THC content?

Measuring the THC content of a strain, known as “potency testing,” is an integral part of the breeders’ work. Generally speaking, samples are sent to a lab to test them. All labs don’t use the same process, but these days testing is highly accurate.

The majority of potency testing uses “high-performance liquid chromatography” or HPLC. This method uses a liquid that contains the cannabis and pressure to figure out the THC levels. Another process called “gas chromatography,” or GC is also sometimes used. It vaporizes the cannabis without decomposing the product and then reads the purity of it.

These tests, generally carried out by an external lab rather than on-site by cultivators, allow growers to know what their breeding efforts have achieved. These tests also help breeders determine which strains are the highest in potency, and therefore which ones to combine with Cannabis ruderalis to make autoflowers that are also high in THC.

Because of this joint effort between breeders and those who measure THC levels scientifically, we are at a point today where the potency of a strain that was previously known for being relatively weak is now very popular among all types of marijuana consumers.

How to Grow Potent Autoflowers

Growing potent autoflowers is not only about breeding and genetics — it also falls to the grower to use specific techniques to increase the potency of autoflower buds. Here’s what you should consider when trying to grow some of the strongest THC outdoor autoflower cannabis strains.

Plant Health

If you want your marijuana plants (whether autoflowers or otherwise) to grow as potent of buds as possible, pay close attention to their overall health from the moment you germinate them. Research optimal growing techniques to prepare for your grow, and give them a try once you have your seeds.

Light levels

The duration, intensity, and type of lighting that you use can all make a big difference in how much THC your buds end up with. Plants that have plenty of light generally grow bigger and stronger — and that includes bigger, juicier buds too. Changing your lighting to LED lighting, for example, is known to help maximize THC levels.

Harvest and Curing

While it’s easy to forget about the stages after your plants’ life cycle, harvesting and curing can make a massive difference in the THC levels of your buds. Time the harvest right so you get as much THC as is possible in the buds, and then cure the buds properly so the supply lasts a long time and the THC doesn’t deteriorate.

Know when to harvest your plants for maximum THC with my free harvesting mini guide.


Genetics is one of the most important determinants of growing autoflowers with high THC.  It is worth paying a little extra for good genetics because they will decide how high the potential is for your buds’ THC levels. Without good genetics, all the other growing efforts could be wasted. Let’s take a look at some of the top strongest autoflower strains.

Top 5 Strongest Autoflower Strains

Zkittlez Auto

Zkittles Auto is well-known for being the strongest indica autoflowering strain. It’s also one of the fastest, taking about two months to grow.  Zkittles has a THC potency of 23%, making it a very potent strain. 

True to its name, Zkittles Auto gives the user a blast of fruit and sweetness. In typical indica fashion, this strain is going to relax your body until you’re cozy and chill. It makes for a great end of the day smoke.

Buy Zkittlez Auto Seeds

When growing Zkittles, keep in mind,  it has a strong odor. This might not matter if you are growing outdoors, but indoor growers should take note. 

Gorilla Glue Auto

This hybrid strain also has high THC levels, reaching 24% at times. This makes it definitely worth the money and effort for the grower. In fact, these numbers make it one of the strongest outdoor autoflower cannabis strains.

Gorilla Glue Auto gets its name from the resin that covers its buds. This resin looks white-ish and resembles glue. The plant and its buds don’t smell like glue, however. Instead, the scent resembles that of pine trees in a pleasant, earthy way. It is an award-winning strain that is beloved by many growers.

Buy Gorilla Glue Auto

The harvest is quite high, and the flowering time is quite short, although not the absolute shortest of autoflower strains. Generally, you will be able to harvest after 9 to 10 weeks. 

Banana Kush Auto 

Banana Kush Autoflower is a slightly indica-dominant hybrid. This strain has a whopping 27% THC but basically no CBD to speak of. It flowers quickly, taking about 8 weeks in total. As its name implies, Banana Kush Autoflower has a sweet, banana flavor and aroma. It makes its users feel happy, relaxed and uplifted.

These compact plants work well for smaller spaces and are best grown indoors unless you live in an environment with warm temperatures (between 68 and 80 degrees Fahrenheit is ideal). Because they are compact, humidity levels should be only at 40% and not any higher. 

Buy Banana Kush Auto

Gold Leaf Auto

Gold Leaf Autoflower is one of our signature strains, and it’s easy to see why. First of all, growing this strain is easy for anyone, even beginners. The plants are compact and will grow happily indoors or outdoors, and the flowering time is only 8 weeks. THC levels are also beginner-friendly, strong but not too strong at 21%.

The aroma and flavor of this strain are beloved by many, what with its earthy, sweet, spicy tones. It is an indica-dominant hybrid (60%/40%) that leaves users uplifted, euphoric, and relaxed.

Buy Gold Leaf Auto

Bruce Banner Auto

Bruce Banner Autoflower is a sativa-dominant (60%)hybrid strain. Its THC levels are high, coming in at 25%, which is significant considering its short grow time (8 weeks). These plants are rather tall, so make sure you have the grow space for them before buying the seeds. 

Its pungent, earthy, diesel aroma is not for everyone, but many people really like it. It leaves users happy, relaxed, and euphoric. This strong autoflower won an award at the Cannabis Cup, which comes as no surprise to those who have grown and/or smoked it!

Buy Bruce Banner Auto

FAQs About Strongest Autoflower Strains

How much light can you give your autoflowering plant?

Give them as much light as you want! Because they are not dependent on changes in light for their life cycle, giving them a ton of light will not disrupt their growth or flowering phase

Are autoflowers high in CBD?

The strains listed in this article are focused on THC and do not have much CBD (if any). However, many autoflower strains are high in CBD, making them ideal for those looking for an easy growing marijuana plant.  Find high CBD strains in our store. 

Do autoflowers have lower yields?

Because autoflowers are smaller in size and have a shorter life cycle, their yields are generally smaller than photoperiod marijuana plants. However, you can maximize their yields and potency with expert growing techniques, as covered in this article.  

You only need practice and learning to grow marijuana like a pro. Let our blog help with all your growing questions.

What’s your favorite autoflower strains to grow? Tell us in the comments below!

Happy growing!


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