Cannabis Indica

GHaze x Dieselryder autoflower

Autoflowering cannabis or day neutral cannabis varieties automatically switch from vegetative growth to the flowering stage based on age, as opposed to the ratio of light to dark hours required with photoperiod dependent/short-day strains. Many autoflowers will be ready to harvest in less than 10 weeks from seed[1] Dwarf varieties can have short stature[2] while still giving decent yield. Conversely "super autos" can take over 100 days to mature and can reach over 6 feet tall.


In botany, a ruderalis plant is one that can grow despite the environment, being able to withstand harsh conditions.

This makes sense as this subspecies of cannabis is highly resilient and enduring. Native to the harsh climates of Russia, central Europe, and central Asia, ruderalis was officially identified in the wild regions of South Siberia by Janischewski, a Russian botanist, back in 1924.[3]

The origins of autoflowering cannabis are still debatable. The strain Lowryder by breeder The Joint Doctor was the original large scale marketed autoflower.[4] Lowryder contains genetics from a Mexican strain that was referred to as Mexican Rudy and is believed to be created from a cross between a Mexican sativa and a Russian Cannabis ruderalis. Another theory is that the early genetics came from the first oilseed hemp variety called Finola, which was developed from Russian stock in Finland during 1995. These early hybrids with large amounts of C. ruderalis genes[5] were lacking some of the finer qualities of high grade cannabis strains available.

Further hybrids from these ruderalis dominant strains were created using some of the more popular and standard photo-period sensitive strains. Since the first mass market autoflower, Lowryder, many improvements have been made by breeders.[6] Because the effect was weak when consuming it due to its low THC levels, autoflowers weren't popular among recreational users.

A couple of years after its characteristics became known, autoflowering strains became of high interest to cannabis breeders. Breeders started developing ruderalis hybrids that had high THC or CBD levels and only needed around 9 weeks to completely mature. These hybrids became known as Autoflowering cannabis, for its ability to flower automatically without depending on darkness, like normal photoperiodic strains.

Nowadays there’s not much difference between photoperiodic and auto strains (other than their flowering conditions, obviously). You can find strains with the same THC and CBD levels in both versions (auto and photoperiod). There even are autos that can be stronger than some photoperiod strains and can have up to 27% of THC.[7]


As of January 2020, online vendors offer more than 1000 autoflowering strains with Sensi Skunk Automatic,[8] Amnesia XXL Automatic,[9] Big Bang Auto [10] and Zkittlez Auto [11] being the most sold varieties in the market. Most of these strains can be identified by the presence of "Auto" or "Automatic" (such as with the Gorilla Cookies Auto bred by Fast Buds [12]) in their names.


The newly produced strains of autoflowering cannabis have proven that they can produce quality medicine comparable with classical short-day strains. Breeders have reported THC content around 25% in some newer varieties while many varieties also have high CBD content.[13] The advantages that autoflower breeders report with their plants include:

  • Short life span with many going from seed to harvest in under 13 weeks (some as short as seven weeks)
  • Can be kept short in stature for "stealth" growing
  • The Cannabis ruderalis heritage causes flowering after 2–3 weeks from germination
  • No need for a separate vegetative and flowering environment (unlike with photoperiod dependent/ short-day strains)
  • Simple seed production, one plant can produce several hundred seeds even at 1 foot (30.5 cm) tall
  • Due to short life span can be grown in cold climates where summers are short and cold[14]
  • Can produce multiple harvests outdoors in one season


There continue to be some photoperiodic cannabis growers that insist that autoflowers are simply a fad and produce subpar flowers. The number one reason for these feelings is the understandable disappointment that many had originally experienced with the results of initial autoflowering strains.

It is also commonly argued that when growing indoors, growers already have the ability to initiate flowering with photoperiod/short-day plants at will, simply by changing the light cycle. Another concern is the overall yield of autoflowering plants, which was really low in the first autos (yielding around a half ounce per plant), although modern autoflowering strains can yield up to 100 g or more. Furthermore, the potency of autoflowers is usually lower than photoperiod varieties. While many autos near or surpass the 20% THC threshold, it is still relatively uncommon to see a specimen reach 28-30% THC. Still, autoflowers should not be underestimated, as their potency is growing higher each year. [15]

The last concern with autoflowering cannabis is the chance of buying genetics that do not actually automatically flower regardless of photoperiod. This can be avoided by buying autoflowering seeds from reputable vendors.

Most of the autoflowering seeds available in the market are feminised. Only a few brands offer regular autoflowering seeds.[16]


Creating true autoflowering seed from two quality, true breeding autoflowering parent plants is easy for most.[17] Breeding new autoflowering strains becomes more difficult when attempting to make a hybrid with a non-autoflowering strain. Some photoperiod/short-day cannabis strains are heterogeneous - containing the recessive day-neutral or autoflowering genetics along with the dominant short-day genetics. However a proper list of such strains is not yet available so most breeders treat all short-day plants as homozygous dominant.

A true autoflower is homozygous recessive[18] for the day neutral genetics. Therefore, most crosses between classical photoperiod/short-day strains and autoflowers produce few or no autoflower progeny in the F1 generation. Regardless of whether the F1 generation produces autoflowering plants, the higher performing and similar plants need to be recrossed. This F2 generation will contain approximately 25% of homozygous recessive plants which are autoflowering. Still the few autoflowers produced are not always stable and may require further stabilization. Further complexities with stabilizing autoflowers has previously led to non-autoflowering and low quality strains making it into the market.

See also[edit]



  1. ^ Downs, David (15 April 2014). "How To Grow Organic Pot". East Bay Express.
  2. ^ David, Steve (2 November 2011). "Hydroponics Autoflowering Marijuana: Seed to Harvest in 70 Days or Less!". Big Buds. Archived from the original on 2014-04-26.
  3. ^ 2020. "What is Cannabis Ruderalis and Its Effects". Retrieved from
  4. ^ "The history of autoflowering cannabis seeds". Canabbis.Info. 7 December 2017.
  5. ^ van Bakel, Harm; Jake M Stout; Atina G Cote; Carling M Tallon; Andrew G Sharpe; Timothy R Hughes; Jonathan E Page (24 October 2011). "The draft genome and transcriptome of Cannabis sativa" (PDF). Genome Biology. 12 (10): R102. doi:10.1186/gb-2011-12-10-r102. PMC 3359589. PMID 22014239. S2CID 10674584.
  6. ^ 2015. "Best Auto Flowering Cannabis Seeds". Retrieved from
  7. ^ 2020. "What is Cannabis Ruderalis and Its Effects". Retrieved from
  8. ^ Sensi seeds. "".
  9. ^ Dinafem. "".
  10. ^ Green House seeds co. "".
  11. ^ Zkittlez Auto. "Fast Buds: American autoflowering seeds".
  12. ^ "Fast Buds: American Autoflowering Seeds".
  13. ^ Gabriel, Larry. 2011. "Beyond THC." Retrieved from
  14. ^ Midowo. "What are autoflowering cannabis seeds". Archived from the original on 2013-10-02.
  15. ^ "Should Beginners Start With Autoflowering Cannabis Strains?". Retrieved 2021-04-14.
  16. ^ Kemar. "Autoflowering Seeds".
  17. ^ Geber, Monica A. (1999). Gender and sexual dimorphism in flowering plants : with 29 tables. Berlin [u.a.]: Springer. ISBN 978-3540645979.
  18. ^ Said, Nuff. "Cannabis Seeds and Basic Breeding". ISmoke Magazine. Retrieved 25 April 2014.

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