Autoflower Cannabis Seeds – Everything You Need To Know

Autoflowering strains are one of the latest additions to the Cannabis seed catalogue.

They have proven to be very popular among veteran and beginner cannabis growers alike.

But what are they? And what are the benefits and drawbacks of using them?

In this article, we will get to know the benefits, disadvantages and main characteristics of autoflowering cannabis seeds, read on!

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What Are Autoflower Seeds?

Many plants have two growing stages, a vegetative stage in which they grow in size and produce leaves and branches, and a flowering stage in which they direct their energy into making flowers or fruits.

Most Cannabis species, including both Cannabis Indica and Sativa, are photoperiod dependent.

This means that the switch to trigger flowering is determined by a reduction in light hours and the appearance of long nights of at least 12 hours of darkness.

Cannabis Ruderalis is different; it is not photoperiod dependent as it doesn’t need a change in light hours to initiate flowering.

Instead, flowering starts automatically once the plant reaches a certain age.

Autoflower Seeds are commercial seeds that have been crossed with Cannabis Ruderalis and have acquired the gene that allows them to begin flowering after a certain age.

Instead of being dependent on the light cycle.

By breeding high THC or CBD strains with Cannabis Ruderalis, they have developed strains that can flower independently of the light cycle while still achieving high levels of THC and CBD.

Benefits of Using Autoflower Seeds

Fast flowering

Autoflowering cannabis strains are the champions of speed, with most being able to go from seed to harvest in less than 12 weeks.

Some can even reach full maturity in as little as seven weeks; this is roughly the same time a photoperiod strain would spend on flowering alone.

The quickness of autoflowers is what makes them attractive to many growers who want to have perpetual harvests indoors while eliminating the need for separate vegging and flowering spaces.

This fast-flowering gene also allows growers to be able to cultivate outdoors in extreme weathers with short summers.


Most autoflower strains tend to stay short in stature, usually reaching heights of between 60 to 100cm, thus allowing people to grow them on balconies or inconspicuous locations in your garden without the neighbours finding out.

Autoflowers are also very resilient and can easily fend for themselves against pests, insects and mould.

This resiliency makes them a favourite of guerrilla growers who grow in hidden or wild locations and need to leave their plants unattended for weeks at a time.

They can also be quite convenient for people who want to grow indoors but don’t have a lot of space because you don’t need separate vegging and flowering areas.

With autos, you can even get away with micro-growing, which means cultivating tiny plants in modified computer towers, buckets, and boxes.

Easy Lighting

The fact that autoflowers are not affected by changes in light schedules makes it much easier to control lighting.

Most autoflower growers use a light cycle of 18 hours on and 6 hours off for the entire duration of their plant’s life.

Another popular lighting schedule used with autoflowers is 24/0, meaning you give the plants 24 hours of light and no darkness from seed to harvest.

This kind of light cycle increases electricity costs, but I have proven that it greatly maximizes yields.

Autoflowers can even grow with short light cycles of 12 hours on, 12 hours off, while this can significantly reduce electric costs, it will also come with a loss in yield.

Another advantage of autoflowers is that they are not affected by light pollution; light pollution is when external light sources interrupt a cannabis plant’s dark cycle.

While this is a non-issue with autoflowers, it can be highly stressful for photoperiod plants.

Resilient plants

Autoflowering strains are highly resilient and hardy thanks to their Ruderalis background, this makes them ideal for beginner cultivators because they are not affected by changes in light schedules or interruptions in the dark cycle during the flowering stage (light leakage).

Most autoflowers are also very resilient against different diseases, pest infestations don’t seem to affect them as much as their photoperiodic sisters, and they also defend themselves well against crop-ruining mould.

Fewer Nutrients Required

One significant advantage of autoflowers is that you don’t need to spend as much on nutrients.

Autoflowering cannabis strains are crossed with Ruderalis, and the Ruderalis gene makes them require low amounts of nutrients to thrive.

Beware that it’s easy to overfeed autoflowering plants, and that nutrient burn can be a genuine problem, be careful.

Higher CBD

Cannabis Ruderalis is much higher in CBD than its Indica or Sativa counterparts.

Allowing breeders to produce high CBD versions of their famous strains by crossing them with Ruderalis genetics.

However, nowadays breeders have achieved autoflowering strains high in CBD, high in THC, and those with an equal balance of both, not to mention the vast diversity in terpenes and other cannabinoids.

Negatives of Using Autoflower Seeds

Lower yield

The main disadvantage of autoflowering strains is their lower yield due to their smaller size and shorter lifespans.

The canopy of autoflowers usually has fewer bud sites than would be the case with photoperiod strains.

Outdoor yields for autoflowering plants are usually under 100 grams per plant. In

comparison, with a regular photoperiod strain, you could achieve outdoor harvests of over 500 grams per plant.

Another disadvantage is that autoflower buds are usually very fluffy and not compact as with regular strains.

Cost of lighting

Most autoflower growers choose to use a simple light schedule of 18 hours on and 6 hours off during the entire duration of their harvest like you would do during the vegetative stage of photoperiod strains.

However, with light-sensitive plants, once you enter flowering and reduce your hours of light to only 12 hours a day, electricity costs go way down, while with autoflowers they stay the same.

Also, as some growers choose to give their plants 24 hours of uninterrupted light, electricity costs can ramp up quickly.

Lower THC content

Cannabis Ruderalis contains minimal THC, and early autoflower strains also suffered from this same problem.

This first trait led some people to think of autoflower cannabis plants as lower quality than more conventional and traditional types of cannabis.

Also, compared to the same photoperiod strains, they tend to have slightly higher levels of CBD; for example, GG4 has lower levels of CBD than GG4 auto. However, this can be seen as an advantage by some people.

However, by perfecting their techniques breeders have achieved strains with high levels of THC, some breeders have even reported autoflower strains with upwards of 25% THC.

Poor-quality clones

This one is true, while it is possible to take a cutting from autoflowering strains.

These cuttings will have the same biological age as the plant they were taken from and will produce buds at around the same time regardless of size and development, which will result in small plants with minimal yields.

This is the reason autoflowers are always grown from seeds and not cuttings.

No time for recovery

While many photoperiod strains can benefit from different topping and pruning techniques to increase yield, the short vegetative period makes it less than ideal with autoflowers.

Since autoflowers begin flowering at around 3 to 4 weeks from seed, they don’t have the time to recover from these invasive techniques as photoperiod strains do.

It is advisable to grow autoflowers with a single cola that will give you large yields, and stay away from topping, which will probably only hurt your crops.

Autoflower History

Cannabis Ruderalis:

The name “ruderalis” stems from the Latin word for rubble and in botany it’s used to describe plants that can grow under very harsh weather conditions.

Such is the case of Cannabis Ruderalis which adapted to the cold and harsh climates of Central Asia, Eastern Europe, and Russia.

In fact, it is not difficult to find them growing in urban settings thriving in broken ground, close to demolished buildings, and in roadside ditches.

It was precisely in one of the harshest areas of Russia, a wild region of South Siberia, where Janischewski, a Russian botanist, officially identified Cannabis Ruderalis in 1924.

It was also found out that the genus discovered by Janischewski had evolved from leftover hemp plants that were forced to adapt to the harsh climate.

As such, the Ruderalis plant can probably be considered a wild variety of Cannabis Sativa that stays short and bushy and adapted to flower in the harsh climates of northern latitudes.

The Autoflower Gene:

The ability to autoflower didn’t occur by accident; it was a survival mechanism in response to extreme climate conditions.

The very short summers of northern latitudes forced Cannabis Ruderalis to abandon the strategy of waiting for the light cycle to trigger flowering and instead developed an autoflowering gene that would ensure the reproduction of the species.

Present and Future of Autoflowering Cannabis:

Although the original Ruderalis plant contained little to no THC, breeders have achieved some incredible autoflower genetics by crossbreeding Ruderalis with some of the most established strains.

At first, the project was mostly unsuccessful.

Many breeders were not particularly fond of this new genetics, as early autoflower strains had low yields and THC levels.

One of the first successful breeders to experiment with Ruderalis genetics was Neville Schoenmaker, founder of Sensi Seeds, originally known as “The Seed Bank”.

He is also credited as being one of the first to create stable autoflowering crosses.

It’s important to mention that breeders rarely cultivate pure ruderalis strains outside of breeding operations, as the yield is deficient.

However, cannabis enthusiasts have successfully bred potent photoperiod strains with ruderalis genetics, thus creating autoflowering versions of legendary varieties.

Thanks to these early enthusiasts now the market is full with exciting autoflowering strains that can be ready to harvest in 60 days from seed, don’t need to follow demanding light schedules, stay between 50 to 100 cm and contain 20 to 30 % THC.

Super autoflower strains

The newest arrival to the Cannabis seed market are Super Auto strains or XXL strains.

The goal of these super strains is to be larger and more productive than regular autoflowers, while still sharing the same autoflowering gene.

The idea behind the super strains is that they are larger, but still share the same useful trait of flowering automatically.

Some incredibly successful super auto strains can yield as much as regular photoperiod plants.

Autoflower FAQ’s

What does Autoflower mean?

Autoflower refers to cannabis strains that will automatically start flowering (producing buds) after a certain amount of time, as opposed to photoperiod strains that require a specific light/dark cycle to begin making flowers.

Are Autoflower seeds easy to grow?

Autoflowering seeds can be considered easier to grow than photoperiod strains since they are less sensible to rookie mistakes such as problems with light schedules or interrupted dark periods.

One thing to keep in mind, though, is that autoflowering strains don’t respond well to stressful pruning techniques, as their short life cycles won’t give them the necessary time to recover.

Are autoflowers less potent?

The first autoflower crosses were indeed less potent than their photoperiod counterparts.

However, after years of successful breeding, it is possible to find autoflower strains with the same levels of THC and CBD as photoperiod strains.

Nowadays, not only are autoflowers as potent as photoperiod strains, but they also have several advantages to them.

Who has the best autoflowering seeds?

Most reputable seed vendors offer stable and reliable autoflower seeds.

My best experiences have been with Sweet Seeds of which I have grown Speed Devil Auto, Cream Caramel Auto and Black Cream Auto.

What is the difference between autoflowering and feminized seeds?

Feminized cannabis seeds are seeds that have been altered to eliminate male chromosomes so they will only give you female cannabis plants while sharing all the same characteristics as photoperiod strains because they are, in fact, photoperiodic.

Most growers prefer this because only female plants produce buds with high cannabinoid levels that can be smoked or used for oils or extracts.

Autoflower seeds, on the other hand, are bred with Cannabis Ruderalis to include the autoflowering gene.

Most autoflowering seeds you can find on the market today are feminized, but that doesn’t mean all feminized seeds are autos.

Most feminized seeds are simply photoperiod seeds that have been treated to only produce females.

On the other hand, autoflowering seeds also carry the gene that makes them flower independently of the light cycle.

Do Autoflowers produce seeds?

Yes, autoflowers do produce seeds as regular photoperiod strains; however, being able to produce stable autoflower seeds is not an easy task.

Breeders who intend to make seed from their autoflower strains will first need to grow both a male and female autoflowering plant, allowing the male plant to pollinate the female plant.

Crossing an autoflowering strain with a regular photoperiod strain will usually only produce photoperiodic seeds.

What is the strongest Autoflower?

At the moment of writing the three most potent autoflowering strains are Gorilla Cookies Auto with 27% THC, Strawberry Pie Auto with 26% THC and Gelato Auto also with 26% THC.

How do you maximize Autoflower yield?

Since topping and trimming are out of the question due to the short life cycle of autoflowering strains, the two best ways of maximizing yields are LST (Low-Stress Training) and SOG (Sea of Green).

LST is a technique where you carefully bend the new and flexible branches and tie them either to the ground or side of the growing container, having the branches separated from each other will allow the plants to better utilize the light while keeping stress levels low.

SOG or Sea of Green is a technique where you grow many plants in a reduced space, as many as 20 in one square meter, which will allow for a fast flowering canopy of small plants that together can give a very productive harvest.

Another good advice is not to repot your autos but to let them grow in their final containers; this will reduce stress and avoid interruptions in the plant’s growing cycle.

Do Autoflowers need direct sunlight?

While autoflowering cannabis plants can adapt to a wide array of lighting conditions, they, like most plants, benefit from direct sunlight or other strong light source such as HID

(High-Intensity Discharge), usually very high powered sodium or magnesium powered lamps, or high powered LED grow lamps to produce quality yields and achieve their full potential.

How much do Autoflowers yield?

Usually, autoflowers yield 30 to 50 grams per plant. However, some breeders have achieved some Super or XL varieties that can produce over 100 grams per plant.

Can Autoflower seeds be male?

Yes, autoflower seeds can be male, although they are not as commercially available or easy to find as feminized autoflower seeds.

They are mostly only used by cannabis breeders to create stable autoflowering males which can then be crossed with autoflowering females to develop new varieties.

How long do Autoflowers take from seed to harvest?

Most autoflowers go from seed to harvest in under 13 weeks, with some exceptionally fast varieties being able to go from seed to harvest in 7 to 8 weeks.

Do Autoflowers need darkness?

This is a topic of debate; some growers defend the idea that 24 uninterrupted hours of light will increase yields of autoflowering varieties.

At the same time, other breeders argue that a dark cycle is necessary for the healthy development of plants. In my personal experience, there is a definite increase in yield the more light hours the plants get.

Can you take cuttings from an Autoflower?

It is possible to take cuttings from an autoflower.

However, since the cutting will have the same age as the parent plant and will enter flowering together, it’s not advisable to grow autoflowers from cuttings.

Because they would have to recover, vegetate and flower in a matter of 5 to 6 weeks which will result in plants no bigger than a few centimetres and with incredibly low yields.

Do Autoflowers need darkness?

This is a topic of debate; some growers defend the idea that 24 uninterrupted hours of light will increase yields of autoflowering varieties.

At the same time, other breeders argue that a dark cycle is necessary for the healthy development of plants.

In my personal experience, there is a definite increase in yield the more light hours the plants get.

Can you take cuttings from an Autoflower?

It is possible to take cuttings from an autoflower.

However, since the cutting will have the same age as the parent plant and will enter flowering together, it’s not advisable to grow autoflowers from cuttings.

Because they would have to recover, vegetate and flower in a matter of 5 to 6 weeks which will result in plants no bigger than a few centimetres and with incredibly low yields.

Can you grow Autoflowers without nutrients?

Autoflowers certainly need fewer nutrients than photoperiodic strains, but that doesn’t mean they won’t benefit from nutrients at all.

As a rule of thumb try to give autoflowering strains half to a quarter the amount of nutrients you would give to a photoperiodic strain.

How tall do Autoflowers get?

Most autoflowers don’t grow very tall, between 60 to 100 cm. However, some XL varieties can grow up to 150cm or more.

Should I top or trim Autoflowering strains?

It is not recommended to top or trim autoflowering plants because their short vegetative phase won’t allow them to recover from the stress before flowering begins.

James Alexander James Alexander
Hey, I'm James! The founder and head writer here at I started this site to share my passion and knowledge of all things cannabis. I used to work as a budtender in central Amsterdam, and have over 7 years of growing experience.

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