Nebula’s 2024 Guide to Cannabis Auto-Flowering Strains

Last updated Jan 06, 2024

by Nebula Haze

It’s 2024, and there’s never been a better time to grow an auto-flowering cannabis strain. Why? New auto-flowering strains grow amazing bud quality, faster than ever before. View our list of recommended autoflowering breeders, and best autoflowering strains in 2024.

What are cannabis autoflowering strains? Autoflowering cannabis plants tend to stay small and are ready to harvest in 2-3 months. Some strains are even faster, for example Fastbuds autoflowering strains are often ready to harvest in less than 2 months from germination! Auto-flowering strains are ready to harvest several months sooner than standard (photoperiod) cannabis strains. Autos have another cool advantage for indoor growers. While photoperiod cannabis strains need daily dark periods to start making buds, auto-flowering strains start making buds/flowers automatically after a few weeks (“autoflower” stands for automatic flowering). This simplifies the home grow process because marijuana growers don’t need to put grow lights on a timer or think about light leaks.

Auto-flowering cannabis plants are like houseplants on steroids. Unlike standard cannabis strains, they tend to stay small and are ready to harvest just 2-3 months from germination.

Auto-flowering plants usually don’t get enormous due to their short lifespan, but they can produce multiple ounces of bud per plant when grown in optimal conditions with lots of strong light.

This Ultimate Auto in a 2-gallon fabric pot was harvested 65 days from germination and produced almost 4 ounces of prime bud on one plant.

Ultimate Auto buds at harvest

Purple Kush Auto is a smooth pleasant strain and 100% of the autoflowering plants grow purple buds.

Why auto-flowering strains are great:

Grows like a regular house plant (on steroids) – Just germinate the seed and keep plants alive until harvest. Voila, you’ve got buds! Auto-flowering plants don’t need special light periods to make buds like photoperiod strains. Even a sunny window can produce a few grams of buds from an auto-flowering plant. However, it’s important to remember that light is the plant’s “food”. More light equal more buds (up to a point) and you need more than a sunny window to produce a lot of weed. One of the best options for home growers to produce multiple ounces of bud per plant is a cannabis-specific LED grow light.
Ready to harvest in 2-3 months – While standard photoperiod strains typically take 3-5+ months from seed to harvest, autoflowering strains are ready to harvest in just 2-3 months from germination.
More harvests per year – The ability for a 2-month grow period let you harvest up to 6 times a year compared to 3-4 harvests a year with photoperiod strains.
Hundreds of strains to choose from – There are auto-flowering strains with almost any combination of THC and CBD to suit your personal needs. There are also auto-flowering versions of popular and legendary strains.

Cons to auto-flowering strains

Reduced strain choice – Auto-flowering strains do have lots of options, but they are a relatively new (and boutique) type of cannabis so there are not as many options as photoperiod strains. You also need to be extra careful who you buy auto-flowering seeds from because some breeders sell questionable auto-flowering genetics.
Plants stay small if you run into major problems – An auto-flowering plant gains its full size within about 6 weeks from germination, then the plant stops growing any bigger and focuses all its energy on fattening buds. This short growing period means a plant may stay small forever if itgets stunted during the first 4-6 weeks of life. This is opposed to photoperiod strains which need dark periods to start making buds, which gives you as much time as you want to grow plants to the desired size.
No advanced training techniques – Plant training techniques like manifolding or schwazzing aren’t suitable for auto-flowering strains due to the shorter grow period.

Want to give auto-flowering strains a try in 2024? Continue reading this article to learn how to grow auto-flowering plants so they produce potent, high-quality weed.

Autoflowering plants stay very small when grown in small pots with a small grow light

Autoflowering plants get much bigger when given plenty of light plus room for plants and roots to spread out. A 2’x4′ grow tent can produce up to 1 pound of cannabis if you fill it with auto-flowering plants.

The final size / yields of auto-flowering plants is determined by their genetics, their care (how well you treat them), and how much light they get. These plants were the same strain, but the smaller plant was grown under a much less powerful grow light.

If you give your auto-flowering plants water, nutrients, and a good environment, you can produce a surprising amount of bud in 2-3 months.

The biggest downside to auto-flowering plants is plants stay stunted and small if you run into major problems during the first several weeks of life. That can dramatically reduce yields since a small plant can’t support a lot of buds.

Here’s an example of an auto-flowering plant that was overwatered as a seedling and stayed small. At 6 weeks old, it stopped growing any taller and was only a few inches tall at harvest.

Auto-flowering Window Plants?

Auto-flowering cannabis strains are kind of like a regular houseplant in their care, except they need much more light and nutrients.

A long as you keep an auto-flowering plant alive and healthy (and ensure it gets several hours of bright light every day) it will produce buds that are ready to harvest in 2-3 months.

An auto-flowering plant in a window can be a fun way to get started growing weed without investing in a grow light.

Even a window auto-flowering plant can produce a few grams if you take care of it.

The above plant produce 3.5 g after being grown in a sunny window.

In contrast, a photoperiod strain can’t be grown in a window because it needs 12-hour dark periods every day for 8-12 weeks in order to make buds. A photoperiod plant that gets light during its dark period will re-veg, which makes buds wither away and die.

Side Note Based on the Cat in Picture: Never leave a dog or cat alone with a cannabis plant or you may find nibbles on the leaves. Cannabis leaves are generally well-tolerated by cats or dogs (and some pets find cannabis leaves calming), but pets can harm or knock over your plants. This particular cat (my calico) will methodically take a bite out of every leaf if left alone with a plant for even a second.

Many cats and dogs love eating cannabis leaves. I collect extra leaves and feed them to my kitty separately 🙂

What Auto-Flowering Strains Should You Get?

If you want to get great results with auto-flowering cannabis plants, you must choose great genetics. Auto-flowering strains were developed from cross-breeding a type of hemp and the first commercial strain (called “Lowryder”) was released in the 2000s. In the beginning, all auto-flowering buds were small and relatively non-potent compared to their photoperiod counterparts.

All auto-flowering plants descend from the humble Ruderalis cannabis plant from northern Siberia. These tiny hemp plants developed the auto-flowering characteristic as an adaptation to the short 2-month summers near the arctic circle. Cannabis breeders have crossed these hemp plants with standard cannabis strains to create auto-flowering strains that produce potent fat sticky buds.

These adorable Ruderalis hemp plants are the ancestors of all auto-flowering strains

Dedicated growers have slowly created auto-flowering strains that produce buds as big and potent as photoperiod strains. As of 2024, many auto-flowering buds match or in some cases even exceed the quality of photoperiod buds.

However, due to this breeding history, there is incredible variation between the worst and best auto-flowering strains. Unfortunately, some breeders still sell older or subpar genetics. It’s especially important when ordering auto-flowering strains to choose a trustworthy breeder that uses modern auto-flowering genetics. Here are some examples of trustworthy breeders and auto-flowering strains.

Recommended Auto-Flowering Breeders in 2024

There are many great breeders, but this list is based on my personal experience. These are the breeders I have ordered my auto-flowering seeds from so far for my grows in 2024.

Ethos Genetics

Ships from the US (Maine) through this link. Ethos also specializes in photoperiod strains but has been extensively working on their auto-flowering line since 2020. Not the quickest-to-harvest auto-flowering strains, as they typically take about 3 months from germination to harvest (that seems fast, but some breeders like Fast Buds make autoflowering strains that take as little as 2 months from seed to harvest). However, Ethos offers some of the best smell and bud potency for autoflowering strains. I think of Ethos strains as “sparkly potent smelly genetics” whether it’s their photoperiod or autoflowering genetics.

Seed Supreme

Also ships from US (San Diego, California). A great variety of excellent modern genetics adapted into stabilized auto-flowering seed form. They offer strains bred in-house by Seed Supreme, and also carry strains from other popular breeders. I like that they offer some strains that were developed in other parts of the world like Europe and Africa, which can be hard to get within the US. They are much more likely to offer the strains you’ve heard about/are looking for by name, while Ethos only carries his unique strains. They have a germination guarantee and good customer service. Their auto-flowering strains tend to be high-yielding.

MSNL Seeds

This seed source is based out of the Netherlands, so it tends to arrive fast in Europe, but may take 1-2 extra weeks to reach cannabis growers the US. MSNL only carries their own strains, so the strain selection isn’t huge, but the company is run by a geneticist and their strains have tons of excellent information about them when it comes to effects, potency, yields, grow patterns, etc. I love that you can count on their strains to always grow as expected, and be easy to grow, with excellent bud quality.

Honorable mentions (I’ve ordered autos from these breeders 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. Great bud quality, nice looking buds, and most strains are ready to harvest just 2 months from seed. Fastest autos you can find without sacrificing quality.
G13 Labs – They’ve been in the auto-flowering game for a while and have some real winners in their strain library
Mephisto Genetics – been developing great auto-flowering strains since 2012 (one of the first great auto-flowering breeders), and continue to add new strains regularly. Great germination rates, maybe some of the best.
Sweet Seeds – Colorful strains with relaxing effects and delicious flavors. This breeder is located in Spain and therefore they offer different genetics from pretty much anywhere else. They seem to focus more on how buds make you feel (creative, relaxed, sedated, etc.) as opposed to THC percentages. I like these buds for daytime.

Recommended auto-flowering strains in 2024

3 Most Potent Autoflowering Strains in 2024 – High THC (25% or higher)

These autos have extremely high potency with strong physical and mental effects. All ready to harvest in under 3 months.

Bruce Banner Autoflower by MSNL – Over 25% THC, ready to harvest in about 70 days, big yields. Ships from Europe.
Dos Si Dos Auto by MSNL – Ready in 75 days, THC above 25%. Sweet, fruity buds. Ships from Europe.
Pluto Cut Auto R F3 by Ethos Genetics – Over 25% THC plus about 5% other more exotic cannabinoids for a total cannabinoid content around 30%. Feels very potent, strong body effects. Tends to stay relatively short, with excellent yields. Ready in 80 days. Ships out of the US.

Pluto Cut Auto R F3 by Ethos Genetics is one of the most potent autoflowering strains available in 2024 that ships from the US.

3 Fastest Auto-flowering Strains in 2024 (Under 2 months!)

Ready to harvest in less than 2 months. These are all from the breeder Fastbuds, as they have the fastest auto-flowering strains yet still focus on bud quality and yield.

Blackberry Auto by Fastbuds – As little as 56 days from sprout, purple buds, great smell, excellent yields.
Gelato Auto by Fastbuds – Ready in 56 days from sprout, big yields especially for the timeline.
Green Crack Auto by Fastbuds – I’m not a huge fan of the name, but the strain is a solid choice for growers. Just 56 days to harvest with great yields.

The Blackberry Auto I grew from Fastbuds. Smelled like fruit!

2024 Autoflowering Genetics with Huge Yields

These strains tends to produce bigger, longer buds than the others on this list, which tends to give them the biggest yields for autos.

Amnesia Haze Auto
Cinderella Jack Auto
Haze XL Auto
Orange Bud Auto
THC Bomb Auto
Ultimate Auto – best yields I’ve ever gotten from an auto-flowering strain

Can’t beat the yields of Auto Ultimate – Here’s the last time I grew it!

3 Best “Pretty Buds” Auto-flowering Strains in 2024 (High Bag Appeal)

These are ready to harvest in 3 months or less, for those who want buds that look incredible in pictures with appealing smells.

Banana Purple Punch Auto by Fastbuds – Ready in 60 days, super purple, good yields, high potency/strong effects.
Pineapple Runtz Auto by Ethos Genetics – Around 22% THC with an assortment of other cannabinoids. Starburst sweet smell. Gorgeous sparkly buds.
Purple Lemonade Auto by North Atlantic – Super purple buds, citrus smell, excellent yields, ready to harvest 60-70 days from germination (wait until the full 70 days for the best potency of about 22% THC). Feels potent.

It’s hard to beat the smell, looks, and just overall high-quality impression of buds from Purple Lemonade Auto by North Atlantic.

3 Best Auto-Flowering Strains for Anxiety Relief in 2024 – High CBD (Over 15%), Low THC (Under 1%)

These strains have anti-anxiety properties with subtle mental and physical effects (won’t get you “high”).

Charlotte’s Angel CBD Auto (16% CBD)
Lemon Potion CBD Auto (15% CBD)
White Widow CBD Auto (10% CBD and 10% THC for a 1:1 THC:CBD ratio)

Recommended Strains with Relaxing and Uplifting Bud Effects in 2024

I chose these strains not because they have particularly crazy stats, but because when you grow them, the buds just come out good and tend to be popular at parties.

Here’s the last Zkittlez Auto I grew. A pleasure to grow with excellent bud effects.

The Zkittlez Auto buds grew big, fat, and sparkly. After harvest, the bud quality was excellent.

I hope that helped give you some ideas on strains to grow. Now it’s time to learn how to grow your auto-flowering seeds so you get great results.

How to Grow Auto-Flowering Plants

Here are simple directions on how to grow a cannabis auto-flowering plants from seed to harvest.

1.) Get seeds (recommended strains above)

This one is easy. All auto-flowering plants are started from seeds and any of the choices above will work great. Check out our seeds page for recommendations on where to buy seeds online.

A main thing to keep in mind when choosing auto-flowering seeds is to look at the breeder information and match the strains for a similar amount of flowering time. Avoid growing “tall’ and “short” strains at the same time. The more similar plants grow to each other, the easier it will be for you. Sometimes growing different strains together can cause unexpected problems. I tend to get strains that take 9-11 weeks from seed to harvest and grow to a medium size, which means all my plants tend to “play well” with each other.

2.) Prepare grow light, grow medium, and nutrients

Before you get started growing, you need to make sure your plants have light, nutrients, and a home for their roots.

Not sure what to get? For beginner growers, I recommend getting an LED grow light, using soil or coco as a grow medium, Dyna-Gro Foliage-Pro and Bloom nutrients (can be used in any grow medium) and choosing a 2, 3, or 5-gallon fabric pot as your container.

The Spider Farmer SF-2000 is a great 200W LED grow light that doesn’t make much heat and can produce over 10 ounces per harvest (here’s my review)

I personally believe soil or coco are the best choice for first-time growers. These mediums tend to be more forgiving than hydroponics.

3-gallon fabric pots like the ones here let an auto-flowering plant get big enough to produce big yields, but plants usually won’t get much bigger than this

Dyna-Gro (Foliage-Pro, Bloom) are inexpensive nutrients that work great for growing cannabis in any grow medium including soil, coco, or hydro. Use “Foliage-Pro” during the vegetative stage, and “Bloom” during the flowering stage. Just follow the instructions on the bottle.

Plus

Learn more about what you need to start growing.

3.) Germinate seeds

Once you get set up, it’s time to start growing. There are many ways to germinate seeds. Here’s the technique I use to get nearly 100% germination. But at its simplest, you can stick seeds in a pot about half a knuckle deep.

Germinate your autoflowering seeds and you’ll soon have seedlings. Remember, bigger pots let plants get bigger while using small pots or solo cups will keep plants small.

4.) Water plants

Basically, the idea is to give your plants water when the top starts drying up. Young seedlings only need a little water in a circle around their base at first. Wait until your plants are growing fast before giving enough water to get runoff out of the bottom.

Learn how to water plants perfectly every time.

Seedlings only need a few cups of water at first. Notice how we only gave these plants a little water in a circle.

Once plants are growing fast, you can give them enough water for runoff (remove the runoff immediately). Wait until the top is dry before watering plants again.

5.) Adjust grow light as needed

As plants get taller, raise the light to keep it the recommended distance away from plants. When in doubt, start lights about 24″ away, though many lights can be kept closer.

How far should I keep my light from my plants?

Adjust lights as needed to keep them the proper distance from plants as they grow