Autoflowering Cannabis 101 – How to Grow Autoflowers (Complete Guide)


When it comes to the unique genetics of autoflowering cannabis strains, there are a few tricks that will help you maximize your yield and have a successful harvest. These plants are pre-programmed to produce buds no matter the light cycle they endure. Due to this, they are perfect for beginner growers looking to try growing cannabis for the first time.

These plants have many benefits, as well as some downsides to them. This article will cover everything you need to know about autoflowering cannabis strains.

When looking to buy seeds, most stores carry a few varieties of them, you will come across a category labelled “autoflower”. A special type of cannabis that has its own unique properties. This is when you need to make a decision on what kind of grow setup your looking to have.

Equipment and Materials Used

4 cannabis autoflowering plants growing in an indoor grow tent setup. Two of the plants are purple and two of the plants are white.
The Canna Schools Autoflowering Grow Tent: 2 Green Wild Sharks and 2 Blackberry Autoflowering Plants.

What is Autoflowering Cannabis?

Autoflowering refers to the life cycle of particular cannabis genetics and strains. If it is an auto-flowering seed, then the plant automatically flowers without having to go through a designated timed light cycle.

Furthermore, once they complete there very short vegetative growth cycle (usually only 2 -4 weeks) the buds start to form. This special characteristic especially helps outdoor growers not have to worry about the hours of sunlight each day. This allows them to focus on other areas of the grow.

Due to the uniqueness of the plant, they also look different than regular genetics. These plants are very short and compact and grow only a portion of the size. All these special characteristics combined create a very interesting and fun plant to grow! The very short life cycle and the durability of the species allow growers to be successful in harsh climates, like northern parts of North America where the seasons are shortened.

Indoor Grow Tent Setup with four cannabis autoflowering plants growing. The LED grow light hangs above the four plants.

How to Grow Autoflowering Cannabis

  1. Consider the location: Are you growing the plants indoors or outdoors? This will be the main factor in determining the best harvest times and grow setup to use. For indoor grow setups, read our comprehensive article on it here. For outdoor growers, read our comprehensive article here.
  2. Germinate your seeds: This is the first step in the process of growing your auto-flowering cannabis plants. You need to first get the seeds to sprout! To learn how to germinate successfully, check our comprehensive guide here!
  3. Consider the climate: Autoflowers still need the same climate and weather the regular cannabis species need too! This means if you are growing in the fall or early spring, make sure the plants have enough heat and aren’t getting to much rain if they are outside.
  4. Feed them “light” nutrients: The short growth cycle combined with the small and compact size, means auto-flowering species require much fewer nutrients than regular plants. This means to go “light” on the nutrients and feed them as they need it.
  5. Harvest Sequentially: The main colas will be ready to harvest before the bottom flowers. This is because they are closest to the light throughout the grow cycle and mature the fastest. Harvest these first and allow the lower flowers to mature and thicken up. Doing this will allow you to maximize your yield and get the most out of your plants.
  6. Efficiency: Germinate your next round of auto-flowering seeds as this harvest ends to continue a constant growth cycle. This especially works if you are growing inside and don’t need to worry about external weather forces such as temperature or rain. The short harvest times allow for multiple grows throughout a year, which equals a constant stream of buds every couple of months!
Close up image of a blackberry autoflowering cannabis nug. The purple and vibrant orange stand out. The trichomes are glossed over the flower.
Close up image of one of the auto-flowering plants.

How to Grow Autoflowering Full Video Guide:

How to Harvest Autoflowering Cannabis Plants

Autoflowering plants grow in a unique way that requires a special method of harvesting. This method will ensure all the buds are grown to their full potential and your yield is maximized.

Autoflowering plants are small and compact in size when in comparison to any other strain of cannabis. They only grow from 1 – 4 ft in size and the growth cycle is only around 60 – 90 days.

Harvest Autoflowers Sequentially:

Due to the small size and the speed at which these plants grow, there is not enough time for the plant to form an even canopy. This means the buds at the bottom of the plant won’t get as much sunlight as the ones on the top.

Usually, the main colas are ready to be harvested first, while the smaller buds at the bottom of the plant are still growing and need more time. A lot of auto-flowering cannabis growers lean towards harvesting their plants sequentially instead of all at once. This allows you to harvest the main colas when they are ready. While allowing time for the smaller buds underneath to bulk up and give you the most out of your plant.

Start by cutting down the main colas of each plant and trimming any fan leaves that are still above the smaller buds. Then lower your LED light if possible to allow the light and heat to reach the smaller buds. Usually, these lower nugs will need anywhere from 1 – 3 weeks longer to fully mature.

cannabis autoflowering plant almost ready to harvest. The vibrant green stands out on this plant.

How to Tell When Autoflowers are Ready to Harvest

There are a few tricks to tell when auto-flowers are ready to harvest. The main trick is practice makes perfect. The more times you can experience a grow, the more knowledgable you will be in the next.

But for beginners, there are some easy tricks to tell when your auto-flowering cannabis plant is ready to harvest.

Look at the Pistils:

  • These are the white hairs that first start growing where your bud forms. Over the course of the life cycle, these mature and turn from a white colour to a brown/amber colour. It is said once 50 – 70% of all pistIls are a brown/amber colour, your plant is ready to harvest.
  • The colour of these also determines the properties your bud will have once you smoke it. The white pistils have much higher psychoactive effects. The brown pistils will be more of a “couchlock” high. This variation allows growers to test harvest times and find a preference they prefer! Usually, growers like to do a 50:50 ratio of white-brown or 30:70 white/brown! Its all preference so test out and find what you like!
Comparison showing different life cycles of cannabis buds. When to harvest your cannabis correctly by looking at the colour of the pistils. Purple cannabis flowers.
How to tell when your plant is ready to harvest.

Look at the Trichomes:

  • The trichomes are the most accurate way of knowing when your plant is ready to harvest. The trichomes will go through multiple stages of maturity in the final weeks, which translates to different highs you will experience. You need to be inside a certain time frame in order to get your buds to produce the desired effects you want. You will need a magnifying glass or a jewellers loupe to be able to see the heads of the trichomes in enough detail to tell. They are too small for the human eye.
  • If you harvest your plant too early, the trichomes won’t have any THC in them and will produce no psychoactive effects. These will be clear trichomes.
  • If you harvest late, then the THC will have mellow effects creating a couchlock/ sleepy high. The trichome heads will have an amber/brown colour too them.
  • You need to harvest right in the middle when the trichomes heads are filled with a white/cloudy colour.
microscope zoom of a cannabis autoflowering trichome head. The clear hairlike structures erect outwards.

Look at the fan leaves:

  • These are the leaves that the plant uses to get its energy from. Once these start to die and turn yellow/curl up, you know your plant is not putting any more energy into them and is only focusing on the buds. This will indicate its almost time to harvest!
A  plant with  dead fan leaves circled on the picture. This indicates the plant is ready to harvest.
Dead Fan Leaves Indicating the Plant is Ready to Harvest.

Pros And Cons of Autoflowering Cannabis

There are many positives to cannabis auto-flowering strains but there are some negatives that are also associated with them. These plants are unique and have there own characteristics separate from the usual feminized cannabis strains. This creates different properties that people either love or hate about the species.

Blackberry autoflowering cannabis strain growing in a tent. The main cola is very purple and is ready to harvest.

Pros of autoflowering cannabis:

Sunlight: When growing auto-flowering plants outdoors, you do not need to worry about the light cycle. These plants produce buds no matter the number of hours of sunlight they get each day. This is great for beginners who are just learning to grow! Remember they still need sunlight in order to grow! They just don’t need it specifically to produce buds.

Fast Harvest Time: These plants are known for having incredibly rapid life cycles, from germination to harvest in as little as 2 months sometimes! This is almost triple the speed of usual feminized seeds. This is great for growers who want to see their valuable yield in as little turn around time as possible. When growing indoors the constant and consistent light they get each day, allows them to grow extremely fast and efficiently.

Nutrients: These small plants use a lot fewer nutrients than regular seeds. Due to this growers can easily make sure the plants are always fed enough nutrients and also save money while doing it.

Hidden: These plants are short and bushy which makes them perfect for stealthy grows and hidden from any unwanted eyes. Especially if your growing in a local area where you could have “crop-hoppers” trying to target and steal your grow.

Compact Size: These plants are a lot of smaller and more compact than their sister species. They grow very small and limited in size. This is what makes them perfect for small rooms like bedrooms or closets. As well as they won’t take up to much space in your garden!

weed nug growing in an indoor grow setup. The green leaves are ridged and stick out everywhere.

Cons of autoflowering cannabis:

Yield Size: Autoflowers are very small compared to the usual feminized strains. The yields are reduced and you will never get as much as growing a regular size plant.

Electricity consumption: Autoflowers are able to have a constant light cycle throughout there grow. This could leave to higher electricity consumption. Leaving the light on for a longer light cycle when growing auto-flowering plants could be considered a negative.

Cannabis nug under the LED purple light. It has orange and white pistils growing out of it.


In conclusion to auto-flowering cannabis, there are defiantly more pros than cons. These are perfect seeds for any beginner growers or someone wanting to try something different. You completely eliminate the light-cycle issues associated with growing cannabis as these plants produce buds no matter what. They are small and compact which makes them easy to maintain. They also consume small amounts of nutrients allowing you to feed them very conservatively which saves you money.

In the end, these are an awesome species of plant and will defiantly have a place in the cannabis industry for beginner and future growers. There very fast growth cycle is very attractive to someone wanting a quick turn around time. There are many new genetics coming out that are just getting better and better! We’re excited to see what the future holds for this species!

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