Autoflowering Cannabis FAQ: 7 Must-Know Facts

Autoflowering cannabis varieties have been steadily gaining in popularity over the last five years or so, as improved breeding techniques have created new and better strains. Now, it is possible to grow abundant, high-potency harvests in as little as nine or ten weeks, from germination to harvest.

Autoflowering seeds are a relatively new innovation in the world of cannabis cultivation. Descended from Cannabis ruderalis genetics native to Russia and Central Asia, autoflowering plants do not rely on changes in light cycle to commence flowering; instead, they rely on a different set of triggers, and flower according to age and size.

1. What is Cannabis ruderalis?

Cannabis ruderalis is a putative third species (or subspecies) of cannabis, and is found in northerly latitudes of the northern hemisphere, particularly in Russia. C. ruderalis is notable for its small stature, low cannabinoid levels, hardiness and cold-resistance — and of course, the tendency to flower regardless of light cycles once a certain age and size has been achieved.

Some botanists classify it as a species in its own right, others that it is a subspecies of Cannabis Indica or Cannabis Sativa. In 2003, chemotaxic and genetic analysis of cannabinoid variation in 157 varieties of cannabis indicated that C. sativa and C. indica were two separate species, and that C. ruderalis is a subspecies of C. sativa. However, even this is disputed. In 2005, new analysis revealed that C. ruderalis may indeed be a species in its own right, and a ‘sister’ species to C. indica and C. sativa.

Due to the extreme climate and short growing season of C. ruderalis’ natural habitat, it has evolved to grow, flower and seed in a short period of time, and does not wait until the light levels drop at the end of summer to begin flowering. At this time frosts will already have begun to set in and temperatures will become unfavourable. Instead, once the plant has produced four or five branches and reached a height of around 50cm, it will begin to flower.

Qualities of the C. ruderalis include:

  • Short vegetative periods and short flowering periods
  • Not dependent on light/day cycles to begin flowering
  • Is hardy and resistant to frost and cold climates
  • Always found at 50°N of the equator or even higher latitudes.

2. What are commercial autos and super-autos?

Over the last decade or two, breeders have experimented with crossing C. ruderalis genetics with desirable, high-cannabinoid strains to produce commercially-useful autoflowering hybrids. It is possible that certain other autoflowering landraces may also have played a part in developing the first “autos”, such as a plant known as the “Mexican Rudy”. As the name suggests, this was a ruderalis-type plant found in Mexico. It was used to produce LowRyder, one of the first commercial autoflowering strains on the market.

An autoflowering cannabis plant

The first wave of commercial autos, including LowRyder, were typically very small in stature (usually reaching a maximum of 40cm in height), low in cannabinoid content, and somewhat lacking in flavour and potency.

However, successive generations of crosses and backcrosses have led to the development of a range of higher-potency strains that are generally known as super-autos. Super-autos are also typically much taller and bushier than standard autos and their ruderalis ancestor, and may reach 90-100cm in height.

3. Autoflowering plants do not need darkness

As autoflowering plants are not dependent on changes in the light cycle to commence flowering, they can successfully be grown using a lighting cycle of anything from 16/8 to 24/0. Many growers cultivate their autos under a 24/0 regime; however, some growers believe that anything over 18/6 is overkill and that electricity costs can be reduced with no reduction in final yield.

There is also the possibility that certain hormonal and metabolic processes do occur in darkness, and that allowing your plants to have a “rest” at night-time leads to overall increased health and vigour. However, this is purely anecdotal and there is no empirical evidence to back this up, at least in the case of autoflowering cannabis.

4. Autos can be grown outdoors year-round

If you are lucky enough to live in a mild to warm climate suitable for outdoor growing, the possibilities for growing autoflowering strains are endless. Taking as little as 8-10 weeks from seed to harvest, it is possible to achieve five harvests or more per year if conditions are favourable year-round.

Cannabis plants growing outside

Plus, autoflowers are so hardy that they will grow well as long as conditions remain above freezing. Autos are generally frost-resistant, but permanently-frozen conditions are too much for even the hardiest plant to tolerate.

However, it is important to remember that autos are not fully stabilised in every case (buying seeds only from reputable outlets reduces the risk here) and may take considerably longer than stated. Despite this, even the autos that take the longest to grow outdoors (18 weeks from seed to harvest seems to be the upper limit) are still favourable compared to photoperiod-dependent plants in terms of total grow time.

5. Can you clone autoflowering plants?

This difficulty in cloning autos has led to the general belief that autoflowering cannabis cannot be cloned, as cuttings taken from a mother plant are forced to follow her “genetic timeline” and flower according to age at the same time that she begins to flower. This logic dictates that the cuttings will not reach a useful size, and yield will be negligible.

However, there are some growers that believe otherwise, and who have successfully managed to clone their autos and allow them to continue to grow in vegetative mode, until they are almost as large as their mother. Once they reach their maximum size, they begin to flower.

An autoflowering cannabis plant sprouting from a pot

The key requirement if attempting to clone autoflowering plants is to take cuttings from the lower branches only. These lower branches seem to be more hormonally stable than newer growth at the top of the plant. The main terminal stem, known as the apical meristem, is the first part of the plant to receive the signal that it is time to flower, and this information takes time to permeate downwards and signal the lower branches to flower.

Thus, there is a brief window of time between the first appearance of sexual characteristics (assuming that regular, non-feminized auto seeds are used) and the permeation of flowering hormones throughout the tissues of the plant. This window may be just a few hours, and it is therefore crucial to watch your plants for pre-flowers and take cuttings as soon as they appear.

Once cuttings are taken, they should be kept under low-intensity light in moist conditions until they have rooted. Once rooted, they will undergo vegetative growth until they have reached approximately 80% of the mother’s size, and will produce comparable final harvests.

6. When do autoflowers flower?

For most plants, including regular cannabis strains, there is a gene that controls photoperiod dependency and response. Obviously, in autoflowering plants, this gene is lacking, meaning the plant does not flower as a response to changes in the circadian rhythm.

Scientists still don’t know exactly which gene is responsible for flowering with autoflowering varieties. However, we do know that in this case, flowering is triggered by age rather than changes in light. Most autoflowers will begin to flower between 6 and 8 weeks after planting.

7. How long do autoflowers take from seed to harvest?

Given the fact that autoflowering varieties are generally still a new initiative in the world of cannabis genetics, the time between seed and harvest can vary greatly. In general, a good autoflowering variety should be ready to harvest within 10 weeks of planting. With that being said, this is not always the case.

Autoflowering plants have been reported to take up to 18 weeks between seed and harvest. This might be due to instability in the genetics or perhaps an unreliable seed purchased from an unreliable retailer.

  • Disclaimer:
    Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.


71 thoughts on “Autoflowering Cannabis FAQ: 7 Must-Know Facts”

  1. Allen Kirby

    I planted some auto and they all did as they should except for one and it didn’t start flowering till the days got shorter and matured in October. Took 6 months from seed to harvest could it have been one of it’s parents

  2. fatemeh sadr

    1. Which one of ruderalis tissues has more beneficial components for Business goals؟
    2. What is the harvest per hectare?

    1. Scarlet Palmer - Sensi Seeds

      Hi fatemeh,

      I’m afraid I am unable to answer this question as it’s outside of our area of expertise. Sometimes our other readers will be able to offer their opinions though. Sorry I can’t help you further, and I hope you continue to enjoy the blog.

      With best wishes,


    2. Fred Flintstone

      In a Dunum, you can fit about 2000 plants assuming the seeds are regular seeds. However, when you go to an actual outdoor field, you’ll see much higher densities, but that is because the farmers rely on a much longer growing season and they remove the male plants to give the females more breathing space.

      That being said, you should not expect more than 2 ounces per plant (regular seeds) under such conditions.

      Regarding your first question, I cannot answer that. You must ask God.

    3. How you can ask question like that?! Same like what is the harvest per meter square?! Next time use simple logic if you can!!

  3. Bryan McNamara

    In the article it says “Thus, there is a brief window of time between the first appearance of sexual characteristics (assuming that regular, non-feminized auto seeds are used) …”
    Why would it matter if the seeds are regular or feminized?

    1. Scarlet Palmer - Sensi Seeds

      Hi Bryan,

      If the seeds are feminized, there is no need to watch out for male plants as none should be produced.

      With best wishes,


    2. I believe it is because the author was trying to say that males will appear first, followed in a few days by the appearance of female flowers.

  4. Nathan Dunstan

    Can anyone help. Im doing my first grow and im a bit confused with this. I am in flowering stage atm and wondering do I just carry on giving them 18/6 light schedule until harvest or is it same as photoperiod plants?

      1. No. Ignore Atumae. Autoflowers will flower regardless of photoperiod. They flower in regards to the age of the plant.

  5. Only issue you might have to worry about is having a bag seed that is a make pollinate your autos, otherwise you should have good results

  6. Heres Jonny

    So if growing is illegal there then why do you sell seeds there? You said you cant ship the US for the exact same reason. BTW marijuana is becoming more and more legal across the USA, so when do you plan to start shipping seeds here? I mean, there are a lot of fake companies out there selling your product anyways, and they ship here.

    1. Scarlet Palmer - Sensi Seeds

      Hi Jonny,

      Growing is legal in the Netherlands under certain conditions: you may only have five plants or less, and they have to be grown outdoors. Some other European countries are also allowing cultivation with permits, or under similar conditions. We have many customers in those countries.

      There are also many countries that permit buying, selling, and possession of seeds, but not their cultivation. For those countries, we sell seeds as collectables and souvenirs.

      We would love to send seeds to the US, but even though many states are now permitting cannabis growing, it is still illegal under federal law. Additionally, seeds of any kind being sent to the US need to have the correct agricultural certification; this is something we would have to take care of even if our seeds were legal to ship there. (There are many shops here that sell tulip bulbs as souvenirs, and advertise the fact that their bulbs come with the certificate that makes it possible to take them into the US.)

      I can’t speak for the companies that claim to sell our seeds and ship them worldwide. Our terms and conditions clearly state that we only sell our seeds on the condition that they are used in accordance with local and international law.

      I hope this answers your question, and that you continue to enjoy the blog.

      With best wishes,


  7. If I grow Fem AF seeds outside in same garden as standard bag seeds will they be messed up by any of the non-fem standard plants as they grow together ?
    I was hoping to get a 10 week harvest from AF while standard plants grow over the summer.

    1. Scarlet Palmer - Sensi Seeds

      Hi Joe,

      For legal reasons, we can’t answer direct questions about growing in the blog comments, unfortunately. Our readers will often help each other by sharing information and answering questions, though, which we completely encourage! This article about how to identify male plants might also be of interest to you, as bag seed will contain regular seeds which will produce both male and female plants. I hope this helps, good luck with your gardening!

      With best wishes,


  8. Chase Rieta

    Can you chemically remove the auto from an autoflower strain? Im having an argument with my tissue culture guy and hes bet me 10k that he can just remove the autoflower aspect of a strain making it a standard photo peroid. I told him that autos are not chemically made like feminized but are autos because of them being breed with a ruderalis with an indica or sativa. If the ruderalis was removed you would be making a new strain or something that is nothing more than the other parent besides the ruderalis. Is my thoughts correct?

    1. Scarlet Palmer - Sensi Seeds

      Hi Chase,

      To my knowledge, the only way to stop a strain being autoflowering is to breed the autoflowering traits out of it that were bred in from ruderalis in the first place! However, depending on what type of tissue culture we’re talking about, your contact may have another way of doing it. If this is the case, I’d love to know how it would be done. Let us know if he tells you 😉

      With best wishes,


  9. Daniel Mcdougall

    Do you veg with blue or red cfl,also mars dual veg,bloom,i have 6″ with red cfl…..put it under 600 red in 3 weeks?never tried auto,s.any advice.

    1. Scarlet Palmer - Sensi Seeds

      Hi Daniel,

      Unfortunately, legal restrictions prevent us from answering grow-related questions on the blog. You could have a look at the Sensi Seeds Forum, where there are extensive threads on many aspects of cultivation and it is possible that a similar question to yours has been discussed. Sorry I can’t help you further!

      With best wishes,


  10. Shootingstar

    Hey Scarlet,
    Maybe you’d like to repeat that just once more for all those people who have their head up their arse! My god how many times do you have to tell someone something?
    Scarlet, you do a fantastic job & you are very patient to say the least.???

    1. Scarlet Palmer - Sensi Seeds

      Hi there,

      Thanks for the support 😉 I have to admit it’s way more frustrating to have to tell people that I can’t answer their grow and medical questions than it would be to try to tackle every enquiry that comes my way. However, as the largest and most visible European cannabis seed company, we are right on the frontline if it comes to officials deciding that there is going to be action taken against seed businesses.

      Amsterdam lost a lot of grow shops a few years ago because they were selling gardening equipment and seeds, and were therefore closed down because it was decided this meant they were encouraging people to break the law by growing cannabis indoors and/or under lights (which is illegal, even here). So it’s really important that we stay within guidelines set by our legal advisors, even if this doesn’t seem to make sense to people reading the blog.

      In the meantime, I hope you continue to enjoy the articles, and thanks again for reading!

      With best wishes,


  11. Does ANYONE pay attention to the moderator, Scarlet? The comment section is for COMMENTS, not questions! Apparently no one pays any attention to the actual comments, if they did, they would notice that on no less than 5 occasions the moderator had to state that for Legal Reasons they are NOT ALLOWED to answer questions, and to go to the Forum for any questions. Man, it’s simple shit like this that makes me think that our society as a whole is F’d, if people can’t follow basic, simple directions, how the hell are we gonna solve difficult problems that affect the entire planet. I think it’s time that a global catastrophe just completely wipes out all of humanity, because we’ve become so stupid and lazy that we can’t even be bothered to pay attention to the simplest of tasks.

    1. Excellent post!!(CRUNCH)This is a comment,for those who don’t understand what a comment is….I still love everyone regardless,keep the peace!!peace✌️🤘🏻

  12. Photo seeding an auto would give you 25% auto’s – male and female..
    William/ your plant must’ve hemied, seeds probably have that trait too..!

    No point in cloning auto’s, they won’t grow big.. but don’t take my word and grow some out., good luck.!
    T-5 WILL be good for growing if you keep canopy level and light close to plants ?.
    Hey TheBest, I have auto’s and photos in same tent – what you want is a perpetual grow- meaning you can have plants at all stages of growth in same place.!

    Happy growing guys,

  13. william wallace

    i bought feminized autoflower northern light seeds and they are budding beutifuly but i am finding seeds in there.not a whole lot but seeds nonetheless.i also have other female plants surrounding my autoflower northern lights,but they are just starting to bud,they are no male plants,so why do i have seeds/

    1. Scarlet Palmer - Sensi Seeds

      Hi William,

      Thank you for your comment ? Unfortunately, for legal reasons we cannot respond to grow questions on the blog, but we do have the Sensi Seeds Forum where you can ask a thriving community of gardening fans for advice, share your experiences, and see if your question has already been covered. I hope this helps.

      With best wishes


    2. Females can produce male pollen sacks for survival of its species (sensimilla) meaning very little seed, search through the female flowering plant for the male stamin to prevent seeds, it their survival instinct.

    3. Ralph Higgo

      Hermied due to stress, left too long and last ditch attempt to self pollinate. Or dodgy genetics.

    1. Scarlet Palmer - Sensi Seeds

      Hi Cliff,

      Thank you for your comment ? Unfortunately, for legal reasons we cannot respond to grow questions on the blog, but we do have the Sensi Seeds Forum where you can ask a thriving community of gardening fans for advice, share your experiences, and see if your question has already been covered. I hope this helps.

      With best wishes


    2. There’s a guy on youtube that has a channel where he does a vid every week using T5s with auto flower (ak 47 I think).

    1. Scarlet Palmer - Sensi Seeds

      Hello Thebest,

      Thank you for your comment ? Unfortunately, for legal reasons we cannot respond to grow questions on the blog, but we do have the Sensi Seeds Forum where you can ask a thriving community of gardening fans for advice, share your experiences, and see if your question has already been covered. I hope this helps.

      With best wishes


      P.S. Autoflowering strains are not affected by light cycles the way regular strains are.

    2. Do you really not know the answer to that? Why wouldn’t you be able to grow autos in different stages in the same tent? You keep the same light cycle the whole time, which you already know from reading the above article, so again; Do you really even have to ask this question?

  14. I’m growing a jack flash #5 indoor
    Under led light
    I’m wondering if it can have a longer than 60-76 day flowering time ?
    How do I know the right time to cut them ?

    1. Scarlet Palmer - Sensi Seeds

      Hi Joe,

      Thank you for your comment ? Unfortunately, for legal reasons we cannot respond to grow questions on the blog, but we do have the Sensi Seeds Forum where you can ask a thriving community of gardening fans for advice, share your experiences, and see if your question has already been covered. I hope this helps.

      With best wishes


      1. dennis farley

        about how many times will you have to cross a ruderalis plant with a regular until it becomes a Auto

      2. Scarlet Palmer - Sensi Seeds

        Hi Dennis,

        Thanks for your comment, my apologies for the delay in answering – I had to do a little research to be sure that I was giving you the correct answer. From the information I’ve been given, it’s theoretically possible to achieve autoflowering plants after three generations of breeding a photosensitive plant with an autoflowering plant, then selectively breeding the resulting offspring together. However, most people attempting this use five to eight generations to ensure the autoflowering trait is properly ‘fixed’ in the new strain. It’s also necessary to bear in mind that when interbreeding to bring out a desired recessive trait (autoflowering), you can also end up with undesired recessive traits that result in unhealthy or even mutated plants. If this happens, it can result in needing to start all over again!

        I hope this answers your question, and that you continue to enjoy the blog.

        With best wishes,


  15. Or said you can get multiple harvests, how do you initiate that and also how long in between harvests?

    1. Scarlet Palmer - Sensi Seeds

      Hello Teejay,

      Thank you for your comment ? Unfortunately we cannot respond to grow questions on the blog, but we do have the Sensi Seeds Forum where you can ask a thriving community of gardening fans for advice, share your experiences, and see if your question has already been covered. I hope this helps.

      With best wishes


  16. Need help! I’m growing auto flower in same room as regular. Af is budding regular in veg for awhile yet. Hear there is a big chance it will seed my crop growing together. Kinda confused without a male and female how does that work?

    1. Scarlet Palmer - Sensi Seeds

      Hello Khris,

      Thank you for your comment 🙂 Unfortunately we cannot respond to grow questions on the blog, but we do have the Sensi Seeds Forum where you can ask a thriving community of gardening fans for advice, share your experiences, and see if your question has already been covered. I hope this helps.

      With best wishes


    2. Khris, you are fine as long as your autos are feminized. They are great to run while the rest of your tent is in veg. If you flip to flowering, though on your photos, make sure you harvest the autos when they are ready, because all plants will herm if left going after their “finish” time, and that WOULD seed your others. But as long as you cut the autos down when they are ready, you will be fine.

      1. @Zoey, can you clarify your comment for me please? You reckon if I let a female go past it’s due harvest date that said plant will turn herm’?
        if this is indeed the case would said Herm’ produce viable seed ?
        The reason I ask is that this would be a great way of guaranteeing a decent harvest of seed from an auto(assuming that the process you speak of transfers to auto aswell?)

  17. I have been searching for information to get an Auto back into Veg and find very little to nothing. Maybe light spectrum has more to do with it because under MH is was not flowering. But I switched to HPS and they flowered , I am sad because I really did not want them to flower.

  18. you’re saying that it is anegdotical rumour than in darkness there is some vital processes going in the plant and that there is no need in dark phase…. maybe you should discuss it with this author:

    1. This is a misunderstanding of photosynthesis. Photosynthesis is composed of “light reactions” and “dark reactions” but they both happen in the light; they are happening concurrently in time as ATP and ADP are cycled by different sets of reactions. It is just that the dark reactions are not directly driven by light, but are using the products of the light reactions to “fix carbon” (from CO2). It is a cycle – all occurring in the chloroplast during exposure to light. Just search for “photosynthesis dark reactions” for a full explanation.

  19. Menyuska1899

    Hi! Thx!
    According to grow in the same way they are for example also in 12/12 lighting conditions? the same amount?


    It is easy to clone any Auto as callus culture, in vitro. Callus is undifferentiated and does not respond to photoperiod nor does it flower. It is easy to maintain, grow and reproduce in-vitro callus, then root it and shoot it and you have a clone of the original Auto mom.

    1. Slippery419

      Can you explain please . I have a few feminized auto seeds but want to clone them when I can and have heard stories that it’s impossible

  21. Jeff McKellar

    Well would they work indoors? How much do they cost? Do they come with grow info? How can I get ’em?

  22. Aren’t some of the original Afghani strains also auto flowering?
    Ruderalis seems to have been bred into everything these days.
    Are there any strains that are still pure and have no ruderalis in them?

  23. Ben Weatherstaff

    I must read everything you have written! I just came across your blog while searching fro something on Robert Connell Clarke to add to my fledgling site on medicinal cannabis. I feel fortunate to have discovered you. does Sensi have autoflowering stabilized CBD rich strains, or do they even exist?

    1. Scarlet Palmer - Sensi Seeds

      Hi Jo Ann,

      Sensi Seeds provide a range of autoflowering seeds, which you can find here.

      Thanks for your interest!

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