WHAT IS AN AUTOFLOWER?
As we all know, cannabis is a photo-period plant: it’s flowering hormones are triggered by changes in the light/dark cycle. Thus you can stimulate a 2 week old cutting to begin flowering by giving it 12 hours of darkness, yet a 4 month old plant grown outside will remain in vegetative growth until mid-summer has passed.
Autoflowers are a different breed altogether (quite literally!) and will flower according to the age of the plant rather than the light/dark cycle. This development has been obtained by crossing a ruderelis strain with a standard photo period plant. Unfortunately ruderelis is fairly weak in the desired thc levels so the first autoflower strain developers had to stabilise two dominant traits: the high thc level provided by the photo-period parent and the all important auto gene from the ruderelis strain. As you can expect, early attempts were generally disappointing, and as little as four years ago autos were viewed as unreliable with poor yields and low thc levels. Most sensible growers put them down as gimmicks for newbies.
Today if you see an autoflower seed for sale you can be (reasonably) assured that its THC content will be as advertised, and its auto gene stabilised.
HOW LONG DOES IT TAKE FOR AUTOS TO GROW?
Now this is the big question. Most breeders claim 7-9 weeks, with some even boasting seed to harvest in less. It would be fantastic if one could get 50g per plant after just 39 days, but lets face it, its totally unrealistic. A plant doesn’t grow any faster for having an auto gene, and the dwarf autos that will harvest in ultra quick times are just that: dwarfs and thus yield is limited by size.
Of the 15 or so different commercial strains I have tried, not one of any consequence finished in less than eleven weeks – and the best ones can take anything between 3 and 5 months. If you think about it, this is not surprising: most standard autos start showing their sex at around 21 -28 days (super autos not included) – if you add on a flowering time of 8 weeks (average flowering time for a indica) then you would be looking at 11 – 12 weeks.
AND THIS ONE IS " VERY, VERY LARGE " AND IS PART 1 OF 2
Auto-Flowering vs. Traditional Cannabis Strains
Fastbud #2 auto cannabis strain - Plant #2
Unlike traditional (referred to as photoperiod) strains, autos don’t need any special
kind of light schedule to “tell” the plant to start budding. With a photoperiod strain,
a cannabis plant needs 12+ hours of darkness a day to initiate flowering.
When growing photoperiod cannabis plants outside, flowering naturally begins when
the days get shorter. For outdoor growers, this means that plants must be planted in
the spring, and they grower must choose strains that will finish in time before winter.
Indoor growers cultivating photoperiod strains can initiate flowering at will by
giving plants longer dark periods (usually by putting their grow lights on a timer).
For indoor growers, this means the grower needs to make a light-proof grow space to allow
for 12 hours of uninterrupted darkness each day while the plants are flowering.
For an auto-flowering cannabis plant, a grower doesn’t have to worry about light
schedules. Each auto-flowering plant starts blooming after a few weeks no matter
what light schedule is provided. For outdoor auto growers, there’s no need to match up
the strain with your local time zone or plant at the perfect time - simply plant autos
when you know you have at least 2-3 months of warm, sunny weather.
When growing auto-flowering plants outdoors, you don’t need to worry about light
schedules. You just need to ensure your plant will have 3 months of warm weather
(above 60°F) and your climate is likely suitable to grow auto-flowering plants. These
auto-flowering plants were ready to harvest before summer was even over:
Example of growing auto-flowering marijuana plants in a homemade greenhouse
For all growers in a hurry to harvest, an auto-flowering plant will almost certainly
be ready to harvest more quickly than any other type of cannabis strain.
More Questions About Auto-Flowering vs Photoperiod Strains
How long until harvest?
What about auto-flowering yields?
Are auto-flowering strains potent?
Are autos a good choice for medical marijuana patients?
How big will each plant get?
Do autos need a special light schedule to start making buds?
Are autos good for growing outdoors?
Can I use plant training methods on autos?
Can I clone plants (make new plants by taking a cutting)?
How long until harvest?
Generally, autos are ready to harvest sooner than photoperiod plants. Most autos are ready
to harvest 2-3 months after being sprouted from seed.
A horde of buds developing…
For the first few weeks, autos (auto-flowering plants) only make vegetative growth - stems
and leaves. After their short “vegetative stage” ends, the plant will start making buds
and continue to grow taller even while their buds are forming.
It’s only until a few weeks before harvest that most auto-flowering plants stop growing
“up and out.” At this point, auto-flowering plants put all their energy into fattening
buds, and buds can gain substantial weight during the last few weeks.
When purchasing auto seeds, good breeders will be able to tell you how long the strain will
take until harvest. It’s important to note that most strain breeders will tend to provide
the shortest time frame they can, and many autos will produce better yields and higher
potency if left for a week or two (sometimes even three) longer than recommended.
How do I know when to harvest my plants? - Basically in addition to the visual appearance of
buds, you can look at your buds under a magnifier to know exactly when to harvest for top
Photoperiod strains usually take longer to harvest than autos. In general, photoperiod
strains are ready to harvest 3-4+ months after being sprouted from seed, though the
final time depends heavily on your grow style and which strain you choose. Even photoperiod
plants flowered from seed tend to take longer than an auto-flowering plant to be ready to
harvest, and the yields are much lower. Photoperiod plants do best when given some time in
the vegetative stage before they start flowering, and aren’t as well suited to quick harvests.
Learn more about how long it takes to grow cannabis plants
Auto-Flowering vs Photoperiod: Which Yields More?
Autos generally yield up to about 4 ounces of bud per plant when taken care of
throughout their life, but the amount of bud produced has a lot to do with the grow setup.
Many growers end up yielding 1-2 ounces per auto or even less, especially if starting
with poor genetics or when using a sub-par lighting setup. Like all cannabis plants,
autos need a lot of light to produce good yields!
In some cases, growers with a lot of experience, great starting genetics and perfect
conditions can yield up to 6 ounces per auto-flowering plant or more.
For example this indoor Dutch Passion AutoMazar plant yielded above 900g
(more than 30 ounces of dried bud) from just one plant under about 1000W worth
of light. Normal yield for this strain is about 100g, so this - admittedly extreme
example - demonstrates what a great setup and grow experience can do for your yields!
Dutch Passion Auto Mazar cannabis plant produces over 30 ounces of bud
View incredible grow review for this plant by “The King”
When considering yields, it’s important to remember that one of the advantages of growing
auto-flowering cannabis strains is most growers can produce several harvests a year
(since the lifespan of each auto plant is very short).
See auto strains recommended by experienced auto growers
Watch time-lapse videos showing Auto-Flowering plants
Photoperiod strains can have a lot more variation in yields than auto-flowering plants. This is due to the fact that photoperiod growers have a lot more control over the size and shape of the plant, which in turn has a huge effect on yields.
Outdoors, your yields depend a lot on your climate. Warm and sunny weather with many hours of light a day will produce plants with bigger yields.
Indoors, generally your setup is the biggest determining factor of your yields.
Learn more about indoor setups and what types of yields to expect
5 ways to increase yields indoors (with any strain)
Which is more potent? What about smell and taste?
This GHaze x Dieselryder auto cannabis plant was grown in soil - Click for closeup!While there are currently fewer auto-flowering strains to choose from, the potency for autos and photoperiod cannabis plants is comparable. Auto-flowering buds are not significantly less potent.
However, one major difference is that many auto-flowering strains tend to have higher amounts of CBD in their buds than photoperiod strains (because Ruderalis plants are high-CBD). CBD is a cannabinoid that is known for having medical properties as well as reducing anxiety.
But in general, a modern “Blue Cheese” auto has been bred to have similar bud characteristics as a “Blue Cheese” photoperiod plant.
Things have come a long way since the original low-potency “Lowryder” auto plants!
Smell, Taste and Visual Appeal - When it comes to smell & taste, the same rules apply. While there are fewer auto-flowering strains to choose from (though the list is growing each day), the smell and taste of each strain is similar to their photoperiod counterparts.
Learn how to improve the smell & taste of your buds
The one visual difference I’ve seen is that auto-flowering buds tend to be a little bit
leafier (grow more leaves among the buds) than photoperiod strains, which means they may
need a little extra care during trimming to get rid of all the leaves.
It’s important to note that some photoperiod strains grow in the same way, and I don’t
believe that extra leaves during the budding process is necessarily a bad thing. If
anything, the extra leaves seem to power the growth of buds, causing them to swell up
more in a smaller amount of time and less light that photoperiod strains.
Are auto-flowering strains better for medical marijuana?
Auto-flowering Northern Lights+ by Nirvana - grown by rollinsd
An important characteristic for medical marijuana patients is that auto-flowering buds tend
to contain higher levels of CBD than photoperiod strains.
CBD is a cannabinoid that is known for having medical and anti-anxiety properties. Most
photoperiod strains these days are high THC, low CBD, and it can be hard to find high-CBD
photoperiod strains. Learn more about THC vs CBD.
This makes auto-flowering buds an attractive choice for some medical marijuana patients who
are looking for higher CBD cannabis strains. There are also auto-flowering strains that are
bred principally to be high in CBD. It’s difficult for many growers get clones of one of the
famous high-CBD photoperiod strains, and auto-flowering strains can make it easier for some
patients to get access to CBD.
When I grew auto-flowering strains, the buds felt more medicinal (as opposed to recreational)
than the majority of strains I’ve grown. Even in higher doses, the effects weren’t as “racing”
as some of the really high-THC, low CBD strains. The buds all made me feel very pleasant and
helped melt away stress, without being overwhelming. I think some people might actually
prefer the effects of auto-flowering buds, even if they’re not patients, and I believe
autos may be a great choice for some medical marijuana patients.
How big will each plant get?
A lightly colored bud doing its thingAuto-Flowering
Autos tend to stay short naturally. In fact, in most conditions it is difficult to produce
very large auto-flowering plants because they have such a short lifespan. They only grow
bigger for about 1-2 months. The rest of their lives are spent fattening buds.
On average, autos grow 1-4 feet tall by harvest time; generally, auto-flowering plants
will stay under 4 feet in height. The final height of each auto depends a lot on the
strain you choose and whether you provide enough light. You can also use some non-stressful
plant training methods like bending tall branches over (low stress training) to help prevent
stretchy autos from getting too tall.
More tips on training auto-flowering strains to grow how you want
Photoperiod strains can be trained to grow into almost any size or shape.
Do autos need a special light schedule to start making buds?
Do auto strains needs a special light schedule? In a way, yes!
Autos Should Get 18-24 Hours of Light a Day for the Best Yields
Why are light schedules important anyway?
Auto-flowering strains will automatically start flowering (making buds) after around 3-4
weeks, a time period dependent on the specific strain. You cannot change this; autos will
automatically start flowering due to an internal countdown. After they start making buds,
they will stay in the flowering stage until harvest time. Harvest is usually 2-3 months
from seed and depends almost completely on the strain.
Therefore, with auto-flowering plants, there is no special light schedule “needed.” The
grower does not need periods of darkness to initiate the flowering stage and get plants
to bud properly. You can grow an auto-flowering plant from seed to harvest even if you
were giving just 12 hours or even 8 hours of light a day and it will still make buds and
be ready to harvest. However, to get the best yields you want to take advantage of the fact
that you can give autos a lot of light each day since more light each day = more growth = bigger
One advantage of this internal timeclock is that auto-flowering strains can be grown outdoor
in a city environment where the ambient light at night may be too bright for photoperiod
plants to be able to make buds. Autos don’t care if they’re exposed to light at night. This
can also be used in warm climates to get plants to grow outside the normal growing season.
For example, as long as it’s warm enough you could start a plant in April outside and it
will be ready to harvest by July, which is much sooner than you’ll be able to harvest any
photoperiod plant (all of which are ready to harvest in mid to late Fall).
Note: The auto-flowering internal clock is why it’s recommended to never take clones from
auto-flowering strains - clones will be on the same time clock as their mother. Learn more
about why it’s not recommended to take clones from auto-flowering plants.
Photoperiod strains need to be on a 12-12 light schedule to initiate flowering. When growing
outdoors, photoperiod plants naturally start making buds as winter approaches and days grow
short. However, most indoor growers put their grow lights on a timer to initiate and maintain
a 12-12 light schedule during the flowering stage until harvest. This need for uninterrupted
darkness is why it’s important to create a light-proof growing environment when growing
photoperiod plants indoors.
The term “12-12” stands for 12 hours of light and 12 hours of dark each day, and it “tells”
photoperiod plants to enter the flowering stage and make buds. During their daily dark period,
photoperiod plants need to receive complete darkness without interruption. This light schedule
initiates flowering, and must be maintained throughout the entire flowering stage until harvest.
If photoperiod plants receive too much light each day, or are exposed to light during
their dark period, they will either produce hermies (bad) or revert back to the vegetative
stage (stop making buds). If you will be unable to provide complete darkness to your plants
during their night period, it’s recommended that you choose to get an auto-flowering
strain, which isn’t affected by light at night.
Are Autos Easier to Grow?
In some ways, auto-flowering strains are more simple to grow than photoperiod strains, but
there are some additional considerations. For example autos do poorly if the grower runs into
major problems during the beginning of the grow because an auto jumps straight into the
flowering stage even it’s not doing so hot.
This auto-flowering cannabis plant was stunted by growing problems, and as a result it will
produce lower yields that its potentialThe auto-flowering White Widow plant pictured to the
right is sick and stunted. Because of the auto-flowering nature of this strain, the grower
was unable to nurture the plant back to health before the flowering stage began. In this
picture, the plant is 2.5 months old (started from seed like all autoflowering plants),
and the buds are nearing their harvest window even though they’re still small and airy.
As a result, the total yields from this plant will be very low (just a few grams). This
can be discouraging as the grower must start over with a new seed in order to try for a
Autoflowering strains begin making buds and continue on their short internal time-clock regardless
of their health. If you make a lot of mistakes, you will not have time to remedy the plant and
you may end up with a small stunted plant.
On the flip side, if your grow doesn’t go as well as planned, at least it will be harvest time
in just 2-3 months, you’ll learn a lot, and you’ll have the opportunity to try again. That
being said, autos are essentially very simple and a first-time grower can easily get a great
harvest on their very first grow. Plus, auto-flowering plants (and cannabis plants in general)
are hardy! As long as you give them basic care, they will reward you!
Photoperiod plants are able to recover from major growing problems in the vegetative stage when
grown indoors because the grower can give the plants as much time as needed to recover before
switching plants over to the flowering stage.
In some instances, photoperiod strains of cannabis may be easier to grow indoors if you are a
new grower because you can give yourself as much time as to fix problems in the vegetative stage.
During this stage, cannabis plants are hardy and can easily bounce back from problems. Even if
you make a lot of mistakes, you can still get big yields because unlike with autoflowering
strains you are in control of when the flowering stage begins.
Once the flowering cycle is initiated, your plants are more “set” as far as their overall
health and structure. Once a cannabis plant starts budding, there is basically a countdown
until buds are ready to harvest just like autos (this amount of time is mostly based on the strain).
Though the plant may have an initial last “stretch” of vegetative growth when the light
cycle is first changed over, as the plant approaches harvest towards the end of the flowering
stage, almost all growth halts except for the development of bigger buds.
Are autos better for growing outdoors?
Auto plants are suitable for growing outdoors in almost any climate that has at least 2-3 months of warm, sunny weather every year.
Requirements for growing auto-flowering strains outdoors are pretty simple…
Lots of direct light each day. Auto plants should receive 5+ hours of direct light each day.
More is better. In general, more light = bigger yields.
2-3 months of warm, sunny weather. When planting seeds, you should ensure that the weather
will stay warm and sunny for at least 2-3 months from when the seed is first planted.
When growing photoperiod plants outdoors, it’s important to make sure you plant your seeds at
the right time and choose a strain that is suitable for your climate.
When growing photoperiod strains outdoors…
Plant in Spring. Photoperiod plants need to be planted outdoors in late Spring, after days
have grown long enough to support a vegetative stage. It’s safe to put plants outside in late
April for the Northern Hemisphere, and late October for the Southern Hemisphere.
You can start plants indoors. Photoperiod plants can be started indoors if it’s too cold to
put plants outside during your spring, or if you would like to grow bigger plants than would
normally be possible in your local environment. Just make sure indoor plants get at least 14+
hours of light each day.
Choose the right photoperiod strain for your climate. A strain suited to your environment
needs to be chosen with your climate in mind to ensure that buds are ready to harvest before
winter. What this means is you need to ensure the strain’s “flowering stage” is short enough
for your climate. The length of a photoperiod strains flowering stage is primarily determined
by genetics; outdoor photoperiod plants will start flowering when days grow short as winter
approaches. It’s important that you choose a strain with a flowering period short enough to
allow buds to mature before it gets too cold or rainy. Cannabis plants cannot survive freezing
temps or torrential rain, so you need to choose a strain that will be ready to harvest before
winter sets in. Generally, “Indica” strains have a shorter flowering stage and are more suited
to colder climates with short summers. “Sativa” strains are more likely to have longer flowering
stages, and are better suited to warm climates with long, sunny summers.
Make sure photoperiod cannabis plants are not exposed to light during their night period.
When growing photoperiod plants outdoors, being exposed to light at night can prevent them
from flowering, or cause them to have other problems. While moonlight or starlight won’t
bother your plants, it’s important they’re not grown near spotlights, street lights, or
other bright sources of light at night.
Can I use plant training methods on auto-flowering strains?
Can I Top an Auto? (full article with instructions)
Auto-flowering strains respond well to very light low stress training (LST) such as bending
the plants to “open up” lower branches to light.
How to LST an auto-flowering plant picture by Santacabrera
Bend too-tall branches down and away from the center of your plant
Plant training is a tactic that helps cannabis growers increase yields indoors by exposing
more buds to strong, direct light from the grow light.
When training autos, the idea is to use bending to open up the plant so it grows flat and wide
Auto-flowering cannabis plants at week 6 - cozy in their tent!
A view from the side so you can see how those plants were trained to grow flat and wide
Auto-flowering cannabis plants at week 6 - a view from the side
Training allows all the bud sites to grow directly under the light, so they get as big as possible
A view of the three auto-flowering cannabis plants outside their tent
See the full grow journal with these autos
Many growers do not recommend exposing autos to plant training methods that involve cutting
the plant (topping, FIMing, main-lining, etc.) as the autoflowering vegetative stage is short
and plants often don’t have enough time to recover before they begin flowering.
Because of the quick time schedule, it is important to avoid stressing auto-flowering plants
during their grow because the plants don’t have time to recover from problems.
However, when plants are fast-growing and healthy, many growers defoliate, top or FIM their
plants with great results. When is it okay to top an auto?
More tips on growing autos below
Since photoperiod plants can be forced to remain in the vegetative stage for as long as the
grower wants, a grower can take advantage of a variety of plant training methods to shape/train
the plant during the vegetative stage, including LST, topping, FIMing, main-lining, ScrOG, etc.
Training methods along with a properly timed light schedule can be used to produce very
small or very large plants…whatever the grower wants!
Learn more about cannabis training techniques here
Can I clone auto-flowering plants?
A clone is when you take a cutting of a plant and allow the cutting to grow into its own plant.
Autoflowering cannabis plants cannot be cloned effectively because new clones are on the same
internal “time clock” as their mother, and therefore any clone taken from her will die when
Because of this, auto-flowering clones live short lives and most growers strongly recommend
against cloning auto strains because they stay extremely small and will not live long enough
to produce good yields.
While autos can’t be used to make clones, it is possible to make seeds using a male to
pollinate a female auto-flowering plant.
Photoperiod plants can be cloned, which means that a grower can continue to make more and
more plants from a single seed. Cloning is a great way to get unlimited free plants which
are almost exactly the same as each other.
So, You Want to Grow an Auto-Flowering Plant!
These buds are weighing down their branches!
Which breeders can I trust for good auto-flowering seeds?
Which breeders can I trust for good auto-flowering seeds? These auto breeders have
dedicated themselves to developing auto-flowering strains in particular, and have
gained popularity for their consistency and quality.
Some Excellent Auto-Flowering Cannabis Breeders:
Mephisto ← Over the last few years this breeder has really taken off with amazing
auto-flowering genetics, highly recommended
There are many other breeders that offer auto-flowering seeds, but the breeders listed have
become famous for breeding some of the best auto seeds when it comes to ease of growth,
potency and yields. Let us know if there’s an auto-flowering cannabis breeder we should
add to this list!
Pictures of Auto-Flowering Plants
Now here are some pictures of Autos (by various breeders and growers) to help give you an
idea of what to expect when growing an autoflowering strain of cannabis.
Dinafem & Dutch Passion - Three Months for 6.7 Ounces
by Nebula Haze
From left to right: Dinafem Critical Jack, Dinafem Sour Diesel, Dutch Passion Blue AutoMazar
A view of the three auto-flowering cannabis plants outside their tent
See the strain review for each of these plants
Using a small 250W HPS light, I harvested 190.4 grams, or about 6.7 ounces, between the
three plants. This was my first auto-flowering grow and I was blown away by the yields,
the time-to-harvest and especially the potency!