The Amazing Accelerated Autoflowering Cannabis Life Cycle

By Michael Coffey
Published: August 24, 2021 | Last updated: August 24, 2021 05:50:40
Key Takeaways

Where did autoflowering cannabis originate? Why does it grow so quickly? Auto expert and enthusiast Michael Coffey dives into the wonders of the outlier known as Cannabis Ruderalis.

Before we discuss the life cycle of autoflowering cannabis, it’s important that we clearly define exactly what kind of weed we are talking about, or at least try to. The confused and oft repeated origins story we are familiar with tells us Cannabis Ruderalis comes from Siberia, was discovered by the Russian botanist Dmitry Janischewsky in 1924, and is more or less regarded as a ditch weed with one redeeming feature: an ability to flower without a critical photoperiod.


More recent conventional cannabis history picks up the story in the early 2000s with the emergence of Lowryder, and the first generation of commercially available auto hybrids. Stories that the genetics escaped from a 1970s University of Mississippi experiment are still floating around the internet amongst various unconfirmed tales of similar escapes from Ottawa. Nobody really knows. All we can be sure of is there are too many holes in the story, and we haven’t really done much to uncover the truth. We can handle the truth; we just never got around to looking for it. Until now.

If lockdowns are good for one thing it’s desk research, and I’ve gone deep to discover the truth. In fact, I’ve been balls deep into scientific cannabis studies for weeks now and I’ve uncovered an inconvenient truth. It’s best to face up to it right now and you don’t have to take my word for it. Okay, here it is from the men of science with impeccable credentials in a 2015 study called “The Genetic Structure of Marijuana and Hemp”: “We conclude that the genetic identity of a marijuana strain cannot be reliably inferred by its name or by its reported ancestry.”


Not convinced? Well, this will absolutely blow your mind. You know how everyone knows all ruderalis is low in THC and basically hemp. Everyone is dead wrong. A recent attempted reintroduction of industrial hemp to Siberia turned out to be a disaster. The Siberian Times reported on October 9, 2013, “We planted seeds of various types, with and without fertilizers,” noted Nimazhap Badmayev, a scientist involved in the project. “Our climate is extremely continental, with low precipitation. So, the plant adapts itself to our dry climate by increasing the concentration of THC (tetrahydrocannabinol).” Hemp turning into cannabis in Siberia of all places. The scientist continued, “No matter how much of this nice foreign hemp you plant, our local conditions will force it out.”

Let’s leave aside the ruderalis and even the indica and sativa terminology and just look at cannabis very simply and differentiate the plant into two types. One is the traditional photoperiod cannabis, and the other is autoflowering cannabis. Both produce cannabinoid-rich buds and exhibit a range of growth patterns. The primary difference between the two is the duration of the life cycle.

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Grower manually pollinating cannabis with a paint brush.

Breeding and Reproduction

Wild cannabis is wind pollinated, but we are not talking about that. The cannabis we grow is domesticated. People selectively breed cannabis and carefully choose breeding pairs. Reproduction is not governed by the laws of natural selection, and survival of the fittest doesn’t apply either. More accurately it’s survival of the dankest.


Photoperiod cannabis has one distinct advantage over autoflowering cannabis because it can asexually reproduce via cuttings, provided there is a human grower in control with the skills to root clones. Autoflowering cannabis can only be meaningfully cultivated from seed as the absence of a critical photoperiod to trigger bloom means you cannot keep an auto in vegetative growth indefinitely.

There is simply no time to take cuttings from autoflowering cannabis as the plant is counting down to bloom from the day it germinates, and this countdown cannot be delayed.

All cannabis these days is a blend of genetics. We don’t have aboriginal cannabis anymore so using terms like indica, sativa, and ruderalis other than to generalize is redundant. If I use them at all it’s for the purpose of categorizing plants based on morphological traits that approximates to the contemporary understanding of these terms.

In fact, most modern autoflowering strains are derived from photoperiod stock, especially the auto versions that swiftly follow the release of new prize-winning photoperiod strains. Most autos are the product of a cross with a photoperiod plant. The first generation of an auto X photoperiod progeny are photoperiod dependent. It’s only in the F2 generation that the recessive autoflowering trait is expressed in a minority. From this point selective breeding will eventually give rise to the true breeding auto hybrid you buy from the seedbank.

Furthermore, many fast-version photoperiod strains are the result of hybridization with autoflowering cannabis. These strains’ parents have been selected from amongst the fastest flowering photoperiod plants from an auto X photoperiod cross rather than for the autoflowering trait, which can still be present as a dormant trait. So, it is entirely possible you have already unknowingly cropped a photoperiod plant carrying the dreaded ruderalis genes.


The paper towel method is my preferred means of germinating cannabis seeds. You may notice autoflowering cannabis seeds tend to germinate slightly faster than the typical photoperiod seed. One to two days instead of the standard two to three days is the average time for an auto bean to split. Many growers will sow their auto seeds directly in the dirt or final container. Autos can handle a transplant. However, with a life cycle of just 75-90 days, a lot of growers don’t want to take any chances and risk transplant shock.

Don’t forget, germination is the starter’s gun for an auto and that bean is going to race toward harvest.

Cannabis seeds germinating

Auto Seedling Stage

The seedling phase lasts for about seven to 14 days post-germination. High, 70 percent relative humidity (RH) and daytime temps within the 68-77°F range are optimal conditions for auto seedlings. As is a standard 18/6, 20/4 and even the 24/0 light cycle that all photoperiod growers are familiar with. With as little as eight hours of daylight, an auto seedling can persevere where photoperiods would wither. Moreover, the hardy auto can endure less-than-perfect environmental conditions. Cooler temps as low as 50°F would stunt most photoperiod seedlings but the ganja grunts can endure.

Resilience is a notable feature of autos but not unique to them. In general, your average auto is more resistant to plagues, pathogens, and environmental stresses than the average photoperiod. The trouble is if things do go wrong in the early stages of growth with an auto seedling you are going to pay for it when you harvest a little or perhaps a lot less than you would have with a smoother grow.

Vegetative Growth

Vegetative growth is fast and furious. And don’t expect all autos to be runts. These days it’s unwise to assume every auto will adopt a compact low-profile growth pattern. Between day 14-30 expect phenomenal plant growth and rapid maturation. Little seedling sprouts can dramatically develop overnight with huge vertical growth surges and prolific branching. The stick of bud with few secondary shoots is pretty rare and you should be prepared for some pruning and/or training to tame the monster auto strains.

Sure, you might have some stocky indica types, but you could just as easily see a real high-rise from sativa-leaning autos. Also, you will be able to sex your auto plant while it’s still in veg (a whole lot sooner than any photoperiod). Preflowers will be obvious by day 30.

autoflowering cannabis ruderalis


There’s no need for a switch to 12/12 for indoor growers and no waiting until late summer for outdoor growers either. Autos are not triggered to bloom by shorter days and longer nights. This weed is wired different and will transition to bloom as it matures, which is usually in or around day 30. Lower RH closer to 50 percent is preferred but enhanced resistance to damp in higher RH environments is not uncommon.

Disturbances to the dark period can be tolerated and won’t stress an auto plant to hermie like a light leak in a grow tent or a streetlight shining in the garden might for a photoperiod plant. The autoflowering cannabis flowering period is much shorter (8-12 weeks) than the common photoperiod. Don’t be surprised if an auto rapidly progresses through bloom and is ready for harvest after 40-60 days of flowering. A total cultivation cycle of 75-90 days is common, although there are a few late-blooming autos with haze genes coursing through them and 100-plus day life cycle.

Autoflowering cannabis really exhibits its outlier status to the fullest during the flowering period. Buds form incredibly fast and are visually comparable in every way with a photoperiod flower forming in fast-forward. High THC, high CBD, a particular ratio of both, you name it, and you can find autoflowering cannabis that delivers the desired effect. Yields have improved greatly in recent years so you can pull down a heavy harvest from autoflowering plants if you choose your beans wisely.

Final Thoughts on Autoflower Cannabis

We will probably never get to the bottom of the mystery of the origin of the species. Lord knows we are still looking for the missing link to explain our own evolution. Recently I’ve heard murmurs from the internet rabbit hole of academics that think maybe humans hibernated once upon a time.

Genetic research breakthroughs might clear all this up in the near future, but until then let’s not get too hung up on what botanists from the olden days or the current era tell us about weed. Most “square” botanists have never smoked a joint in their life and when they hear the name Strawberry Cough, they imagine a mutant coronavirus strain acquired in orchards by strawberry pickers. All that matters is awesome autos are here now and you would be crazy not to take advantage of their amazing, accelerated life cycle in your herbarium.


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Written by Michael Coffey | Cannabis Cultivator, Writer, Photographer, & YouTuber

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Michael Coffey, aka Top Shelf Grower is a cannabis cultivator, freelance writer, photographer, and YouTuber originally from Dublin Ireland. These days he’s on the loose creating dope content from an off-the-grid location somewhere. In 2018 he self-published his first book, Cannabis Cultivation a 21st Century Guide, available on Amazon.

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