The Rise of Autoflowering Cannabis Strains

Last updated Oct 28, 2023

by Nebula Haze

I’ll always remember the phone call after my dad’s second failed harvest. He described how beautiful buds started growing but after a few weeks, they mysteriously shriveled up and died. He cursed his ‘black thumb’ and I remember the next words vividly. My dad said, “Home growers can’t produce good weed. Only professionals can grow the good stuff.”

AHHH!!! With years of experience helping home growers, I knew this couldn’t be further from the truth. Even worse, he wouldn’t believe me what the problem was. I had seen his closet grow setup. I knew exactly what was happening. His buds kept dying because his cannabis plants were getting exposed to light whenever he opened the closet door. For most cannabis strains (standard or “photoperiod” strains), even small amounts of light during the plant’s “night” period can prevent buds from developing properly. But he believed a little light shouldn’t make that big a difference. You know how it is. Dad knows best.

I realized what I needed to do so my dad could keep his pride and still get great results. l sent him some autoflowering seeds, and got Amazon to send him a little growing kit (3-gallon fabric pots, coco coir, nutrients, and a 100W LED grow light I knew worked great). I wanted to make it so he just couldn’t fail. Two months later, he sent a text with no words. Just a picture.

My dad was frustrated after two failed cannabis grows. Then I sent him autoflowering seeds. Two months later he sent this picture showing he harvested almost 3 ounces of frosty bud from two plants.

 

Intro: What’s an autoflowering strain?

Auto-flowering strains are a unique type of cannabis that automatically start growing buds about 4-5 weeks after germinating, regardless of light cycle. This allows them to go from seed to harvest in just 60-90 days, making them the fastest harvest of any cannabis strain.

Unlike “photoperiod” cannabis strains, autoflowering strains don’t need special light/dark cycles to trigger flowering. Photoperiod strains need 12 hours of darkness each day to develop buds, so even a brief flash of light during their night can disrupt them (like you saw with my dad’s grow). Autoflowering strains flower automatically due to their unique genetics, which means they develop buds under any light conditions. This gives you much less to worry about. All you need to do is give light, nutrients, and water. They’ll do the rest.

Typical photoperiod cannabis strains need long dark nights to grow buds. Auto-flowering cannabis plants grow buds no matter what you do!

Autoflowering marijuana plants will make buds no matter what you do

In this article, I will tell you all about auto-flowering cannabis strains: what they are, why they are popular, how they were created, how they compare to other cannabis plants, and how to grow them successfully. Let’s explore what makes them so special!

 

Why are they so popular?

Auto-flowering cannabis plants are so popular because they’re less demanding than standard photoperiod strains. (The ultra-quick harvests don’t hurt either). They aren’t reliant on strict light schedules to flower and develop buds. That means you simply plant, water, and feed them. With auto-flowering cannabis plants, you can even just leave the grow lights on 24 hours/day. However, I recommend putting grow lights on a timer to give only 18 hours of light a day. This saves 20% electricity, plants tend to be harder to stress out (less likely to run into problems), and I’ve found that reducing the hours to 18 from 24 won’t affect yields much.

When auto-flowering strains appeared on the grow scene in the 2000s, their yields and potency were inferior. However, dedicated breeding has vastly improved them. Over the last 15 years of dedicated breeding, auto-flowering bud quality and yields have exploded. Now, bud potency matches most photoperiod strains as long as you’re growing with modern auto-flowering genetics (some great auto-flowering breeders are Ethos Genetics and Seed Supreme, with more recommended breeders listed at the bottom of the article).

Auto-flowering plants have other benefits for home growers. They tend to stay compact and rarely exceed 2-3 feet tall. This makes them perfect for discreet home grows. But with the proper care, these plants produce extraordinary yields, especially if growing multiple together. Check out my 8 auto-flowering plants below that yielded over a pound of premium bud from a small 2’x4’ tent in the corner of my bedroom.

Growing multiple auto-flowering plants in a small space maximizes yields and variety. I grew these 8 auto-flowering plants together under 18 hours/light a day and they thrived.

Here are those auto-flowering plants about a month from germination. You can see the plants are growing fast and have already started producing buds automatically.

Each of the eight plants produced over 2 ounces, resulting in a total of 17 ounces of premium bud at harvest (over a pound!) from a closet-sized grow space. And 8 different strains to enjoy!

These are not typical results but are possible for even a total beginner if you start with good genetics and follow the best practices listed toward the end of the article. Let’s talk about auto-flowering marijuana benefits, including the pros and cons.

Pros

  • Automatically make buds – Unlike with standard/photoperiod strains, you don’t need to worry about light leaks or checking on your plants at night. It won’t bother them. They’re always happy to see you!
  • Potent buds – Bud potency of modern autos is equal to photoperiod strains
  • Plants don’t get big – Well-bred auto-flowering strains tend to grow relatively short and bushy with a lot of huge buds. These plants are easy to train and keep short when you follow the right instructions.
  • Good yields – Can yield as well as photoperiod plants when grown properly (right lights, environment, nutrients, care, watering: tips below!)
  • A single grow chamber – No need for a separate auto and vegetative chamber. You can keep all your plants together.
  • Outdoor growers – Can be grown all year round. As long as you have at least 2 months of warm weather, you can grow an autoflowering plant to completion in any part of the world. Autos with extra short lifespans tend to be more resistant to cold due to their ancestors evolving in the icy tundra of Siberia.

Autoflowering strains can produce multiple ounces of premium buds per plant even though the plants themselves tend to stay small.

Sweet Seeds Black Jack Auto - this plant grew thick and chunky colas

However, auto-flowering strains aren’t perfect. They do have some downsides that you should know before deciding to grow them.

Cons:

  • May not automatically start flowering – This happens to even the best breeders occasionally because auto-flowering plants are natural things and nature likes to play. Out of about 100 auto-flowering plants I’ve grown, I’ve had 1 plant that didn’t auto, or about 1 out of 100. However, if you grow multiple plants at once you can just remove any plants that don’t auto with almost no downside since the other plants will grow more to fill up that space.
  • Reduced strain selection – Since auto-flowering cannabis plants are a “boutique” strain of cannabis, there aren’t as many auto-flowering breeders as photoperiod breeders. However, these days you have hundreds if not thousands of auto-flowering strains to choose from. These are quickly getting popular and new autoflowering breeders are popping up every day.
  • Early problems can stunt plants – Since their whole life goes so fast, autoflowering plants give you less time to recover from mistakes. This may be the biggest downside to auto-flowering plants in my opinion. If plants have a slow start (typically from overwatering), plants have a chance to stay small if they start flowering when they’re still small. With photoperiod plants, you have tons of time to recover from early mistakes because plants don’t start flowering until you tell them. Though luckily with auto-flowering plants you can always just pop more seeds and not have to worry about all your plants being at different stages of life.

If you make mistakes that cause autoflowering seedlings to grow slowly, they can get stunted because they start flowering while they’re still small. This is likely the biggest downside to autoflowering strains.

 

The origins and evolution of autoflowering strains

Did you know autos are descended from plants that grow in rubble, waste, and harsh conditions? Every auto-flowering plant is descended from a type of hemp called Cannabis ruderalis. The term “ruderalis” comes from the Latin word “rūdera”, which means rubble, lump, or rough piece of bronze. This refers to the fact that ruderalis plants can grow in harsh conditions and disturbed lands. In botanical Latin, “ruderalis” is usually used to mean “weedy” or “growing among waste”. A ruderal species refers to any plant that is the first to colonize land after a disturbance removing competition, and many weeds have the term “ruderalis” in their official scientific name.

The harsh Siberian climate with its short cool 2-month summers caused cannabis ruderalis plants to develop the ability to go from seed to buds on a rapid time schedule.

Auto-flowering ancestors were so tough they survived the harsh Siberian climate and still produced buds. Here’s a ruderalis plant in the wild (picture taken in northern Russia). Look how tiny they are!

A ruderalis cannabis plant in the wild - pic taken in Russia

 

Timeline of Auto-Flowering Development

I want to take a moment to commemorate and give thanks to all the amazing people from around the world who worked together over the last 100 years to make autoflowering strains a reality.

  • 1924: Cannabis ruderalis was first scientifically identified by Russian botanist D.E. Janischewsky from wild plants he collected near Saratov on the Volga River in Russia.
  • 1970s: Cannabis ruderalis was introduced to breeders around the world by cannabis enthusiasts who collected seeds from Russia.
  • 1980s: Australian-born Neville Schoenmakers, the founder of The Seed Bank of Holland, experimented with crossing ruderalis with other cannabis varieties. However, he failed to produce a stable and flavorful autoflowering strain.
  • 1990s: Greg McAllister, founder of Mighty Mite Seed Company, successfully crossed a Mexican sativa strain called Guerrero with a ruderalis strain that he obtained from Neville Schoenmakers. He created Mighty Mite, one of the first autoflowering strains that had decent potency and flavor.
  • Late 1990s: The Joint Doctor, a Canadian cannabis breeder, was introduced to Cannabis ruderalis by his Mexican friend Antonio, who gave him some seeds he called ‘Mexican Rudy’. The Joint Doctor was intrigued by the autoflowering trait of these seeds and decided to experiment with them.
  • 2000s (2003 or 2004): The Joint Doctor released Lowryder, a groundbreaking autoflowering strain that was derived from a cross between Northern Lights #2 (an indica strain) and William’s Wonder (a Sativa strain), with some ruderalis genetics added later. Lowryders stayed small and weren’t very potent, but they stayed small and were fast-flowering. It didn’t matter, breeders realized how useful the auto-flowering trait could be to growers, and the release of Lowryder sparked a revolution in autoflowering cannabis breeding and inspired many other breeders to create new autoflowering strains.
  • Late 2000s – The Joint Doctor developed other autoflowering strains such as Lowryder #2, Diesel Ryder, Easy Ryder, and Chronic Ryder. In fact, for many years all autoflowering strains were known as “Ryder” strains like “Purple Ryder” or “White Widow Ryder”. The seed breeder Nirvana started calling them + strains, like White Widow+, but this never caught on.
  • Early 2010s – The breeding world converged around the descriptive term “auto-flowering” which exactly describes what they do, and I believe is an excellent name. Now “autoflowering” is the standard way to describe these strains. When I grew these strains in the early 2010s, I was disappointed with the potency.
  • 2018 – By this point, auto-flowering strains were matching the potency, yields, and bud quality of photoperiod strains. By the time I grew the newly bred autos in 2018, I was blown away compared to what the earlier auto strains were like.
  • 2023 (today) – New auto-flowering strains are continuing to be bred with new trendy photoperiod strains, constantly increasing the quality. Good auto strains today grow better buds than even photoperiod strains a few years ago.

Auto-flowering strains started in Russia, were bred in Holland by an Australian breeder, and were brought to Mexico, where a Canadian breeder turned them into Lowyrder. Since then, auto-flowering strains have been bred all over the globe. Talk about a worldly strain! It took so many people working together to create the auto-flowering strains we know and love today.

Auto-flowering cannabis genetics have been traveling around the world for 100 years! Breeders from all over the globe worked together to bring auto-flowering strains to life.

Auto-flowering cannabis genetics have been traveling around the world for almost 100 years!

 

Are auto-flowering buds as good as photoperiod buds?

In the beginning, auto-flowering strains had pretty poor-quality buds because they are descended from low-potency Cannabis ruderalis, a type of wild hemp. Breeders had limited time to improve them since plants flower and die within just a few months. In contrast, breeders can refine photoperiod strains over many generations by cloning and repeatedly breeding their favorites. With auto-flowering plants, you get one set of seeds per plant, and that’s it.

Luckily, growers didn’t give up. Dedicated auto-flowering breeders have streamlined breeding to keep up with the latest photoperiod strains.

They incorporate trending photoperiod genetics into new auto-flowering crosses, releasing updated versions that match the quality of top photoperiod strains. While photoperiod strains remain on the cutting edge, modern auto-flowering strains typically lag only 1 step behind the newest and best photoperiod strains. Decades of breeding have transformed auto-flowering cannabis strains from their humble ruderalis roots into plants that can produce spectacular buds.

Modern auto-flowering cannabis buds are just as high-quality as photoperiod strains. For example, these THC Bomb Auto nugs I grew are indistinguishable from photoperiod buds and tested at over 20% THC.

THC Bomb Auto buds looks excellent

 

Tips for growing auto-flowering strains

Here are some tips for growing auto-flowering cannabis strains. Don’t miss my full tutorial on auto-flowering strains with more tips!

Getting Set Up

  • Use good equipment – Choose a good grow medium, nutrients, and grow light. Seed examples of recommended grow setups with estimated costs and yields.
  • 18 hours of light per day – Give 18 hours of light a day by putting your grow lights on an electrical timer. Try to make it so lights-off is a few degrees colder than during the day
  • LEDs work great – Autoflowering plants perform excellently with LEDs as long as the grow room doesn’t get cold. Another suitable grow light for autoflowering plants is an MH/HPS combo (MH/HPS is best for a cold grow room)

Note: If growing in a cold grow room, you can give up to 24 hours of light a day so plants don’t get cold when the lights are out. You may need to move the light a little further away if you’re giving extra hours of light because a plant can only photosynthesize so much light in a day.

Autoflowering Plant Care

  • Germinate seeds directly in the soil – Germinate seeds directly in the soil so you don’t have to transplant your seedlings. Starting your seeds in their final pot can help reduce stunting. Learn how to plant seeds so you get great germination rates.
  • Watering – Water plants regularly but try to avoid overwatering, especially when seedlings are small and not drinking much yet. Seedlings only need a little water at a time, maybe 1-2 cups. Learn more about overwatering seedlings. Try to water plants every 2 days, but always make sure to let the topsoil mostly dry out between waterings. If it’s taking more than 2 days for the topsoil to dry, give less water at a time. If the topsoil drying in a day or less, give more water at a time. Consider adding cannabis nutrients to your water (especially as buds start forming) to get the fastest growth and biggest yields possible. Here’s a tutorial with more detailed instructions on watering cannabis plants.
  • Environment – Maintain comfortable, breezy conditions under 85°F/30°C. Cannabis plants like a warm sunny environment, but be aware of too much heat. Luckily that’s not as much of a problem these days due to LED grow lights. Learn more about the optimal environment.
  • Plant training – Do some light pruning during the first few weeks to encourage the plants to grow tons of buds per plant. Here’s a tutorial on how to prune auto-flowering plants to maximize yields.
  • Harvest time! – Woo hoo! Buds are ready to harvest when nearly all the white hairs have darkened and curled in. Buds should look plump and swollen at this point. Check out pictures of ready-to-harvest cannabis buds.
  • Dry and jar buds after harvest – Buds on the plant are about 70% water. That means you should dry buds before smoking them. Bud quality will also improve if you jar the buds and let them age for a few weeks, known as “curing”. Here’s a complete drying and curing tutorial.

Recommended nutrients

Use vegetative nutrients until flowering starts, then switch to flowering nutrients.

  • Vegetative nutrients – Give vegetative (high in Nitrogen) nutrients in the water until the plant is in the flowering stage. Almost any all-purpose nutrients for plants work well at this stage. One super easy option is Dyna-Gro Foliage Pro. Just add 1 tsp/gallon to water.
  • Flowering nutrients – Start giving flowering or “bloom” nutrients (low in Nitrogen) about 3 weeks after you see the first white hairs/pistils/buds. At this point, you’ll notice the plant isn’t growing much taller so it doesn’t need as much Nitrogen anymore. The plant is now focused on bud development, and since buds are the flowers of a cannabis plant, flowering nutrients work great. One super easy bottle of vegetative nutrients is Dyna-Gro Bloom. Just add 1 tsp/gallon to water before watering your plants.
  • Check the pH if you notice discolored leaves – If the pH at the roots is too high or low (typically because the pH of your water tends to be high or low), then your plant will start getting nutrient deficiencies, which look like spots or discoloration on leaves. What do nutrient deficiencies caused by pH look like? (picture guide) Some people get lucky when it comes to pH, but just remember that the first step is to check the pH if you notice any nutrient deficiencies.

Start giving flowering/bloom nutrients about 3 weeks after you see the first white hairs (baby buds). Autoflowering buds should look about like this when it’s time to start giving flowering nutrients.

Cannabis nutrients help auto-flowering plants grow faster and produce better buds and bigger yields.

Cannabis nutrients help auto-flwoering plants grow faster and produce better buds as well as bigger yields

 

Recommended Auto-flowering breeders

There are dozens if not hundreds of excellent auto-flowering breeders. However, I’ve personally had excellent results with these.

  • Ethos Genetics – also specializes in photoperiod strains but has been extensively working on their auto-flowering line since 2020 (sparkly smelly genetics)
  • Seed Supreme –  a great variety of excellent modern genetics adapted into stabilized auto-flowering seed form (also ships from the US)

Honorable mentions (I’ve ordered from these companies in the past and had great experiences)

  • Bomb Seeds – I especially like their THC Bomb Auto for both yields and potency
  • Dutch Passion – excellent yields though not necessarily the highest potency on their autos
  • Fast Buds – auto-flowering plants grow fast and get consistent results
  • G13 Labs – they’ve been in the auto-flowering game for a while and have some real winners in their strain library
  • Mephisto Genetics – has been developing great auto-flowering strains since 2012 (one of the first great auto-flowering breeders)
  • Sweet Seeds – colorful strains with relaxing effects and delicious flavors

So much awesome comes out of tiny little cannabis seeds…

Recommended auto-flowering strains

High THC (25% or higher) – high potency with strong physical and mental effects

High CBD (Over 15%), Low THC (Under 1%) – anti-anxiety with subtle mental and physical effects (won’t get you “high”)

Above-Average Yields

Relaxing and Uplifting Bud Effects

Purple Auto-Flowering Strains

Here’s a Zkittlez Auto I grew.

The buds grew big, fat, and sparkly

After harvest, the bud quality was excellent

Purple Kush Auto is a smooth pleasant strain and buds come in a gorgeous purple.

Feel free to contact us and share your favorite auto-flowering strains with us. I’m always down to try growing some new autos for “testing” purposes.

 

Conclusion

Thank you for reading and I hope you learned something new. Autoflowering strains have come a long way from their humble Cannabis ruderalis roots. Early autos lacked potency and yield, but dedicated breeders have incorporated the latest photoperiod genetics to create auto-flowering strains on par with most photoperiod strains today. For many growers, autos now deliver the perfect combination of quality, ease, and speed.

I highly recommend autoflowering strains for beginners. I’ve seen how they help simplify cultivation by removing the need to control light cycles (plus you can check on your plants at any time of day), and they produce harvests more quickly while making photoperiod-quality buds. Whether you’re new to growing (like my dad was) or just want fast, effortless harvests of spectacular buds, auto-flowering strains are a great choice for many growers.

To learn more, visit GrowWeedEasy.com, sign up for our newsletter, or join our free grow forum. You can also use the search bar to find information on hundreds of other growing cannabis-related topics!

 

About the Author: Nebula Haze

I’m Nebula Haze, founder of GrowWeedEasy.com. I started the site in 2010 to teach people how to grow cannabis at home. Since then, I’ve dedicated myself to helping home growers succeed with their grows and produce professional quality cannabis.

If you found this guide helpful, please share it and spread the word about GrowWeedEasy.com. Together, we can help more home growers grow great weed!

Happy growing! ~Nebula Haze

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