Great Truth! What are “Autoflowering” Seeds


Here you are, planning to grow your first batch of weed. You know the strain, you know the number of plants, you know your setup. But what is this about autoflowers seeds? What are they and how do they differ from other seeds? And, of course, are they worth it? We’re happy to join you on your learning journey, dear reader. Continue on for the compelling answers to your questions: what are autoflowering seeds!

Autoflowering CannabisAutoflowering cannabis, Wikipedia

Straight to the Point: What are Autoflowering Seeds?

Autoflowering cannabis is a small hybrid type of cannabis that begins flowering without being dependent upon changes in the light cycle. They have a faster growth cycle than photoperiod cannabis, they are smaller, they generally require less maintenance, and they can produce a decent yield.

Autoflowers are a great place to start for beginners because they require a lot less maintenance than photoperiod cannabis. You can grow an autoflower from a seedling to a flowering plant on an 18/6 day/night cycle (or even 24/0!), they grow quicker (as fast as 8 weeks), they’re compact so you can fit them in small spaces, and they require less nutrients (because they’re smaller).

The Details! What are autoflowering seeds?

What is the History of Autoflower Seeds?

We know all plants require sunlight, but the amount of sunlight varies between plants and even strains of plants. Photoperiod cannabis reacts to changes in the natural environment, specifically the amount of daylight available during the growing season—as summer wanes and the days grow shorter, cannabis plants begin to flower.

Cannabis likely originated somewhere in the Northeastern Tibetan plateau in present-day China, where winter daylight hours are as few as 10 hours a day and summer daylight hours are as much as 14 hours a day. When we grow indoors, we usually want to simulate these lighting conditions (or a little more) alongside the growth cycle of the plant. As the plant matures, we adjust the lighting (or photoperiod) to induce flowering.

the Volga RiverThe Volga River, wikipedia

Autoflowering cannabis plants are a hybrid between a common cannabis strain (Indica or Sativa) and a third strain called “Cannabis ruderalis,” which probably originated around the Volga River in Russia. Of course, Russia’s daylight cycle is very different from the Tibetan Plateau so ruderalis is a strain adapted to the environment and does not rely on photoperiods to produce flowers, rather it relies on its own maturity. However, ruderalis also lost the aroma and THC content of other cannabis strains.

How Do They Differ from Photoperiod Seeds?

Because autoflowering cannabis is a ruderalis hybrid, it automatically switches from vegetative growth to flowering based on age rather than photoperiod. When autoflowering cannabis first hit the market in the 2000s, it was not popular—the THC levels were low, the plants were small, and the yields were tiny. However, over the past 20 years, breeders have seen the potential of these plants and have brought some great traits out, including pretty large yields, and a good THC-CBD ratio, while keeping the plants small.

Read more to find out what are autoflowering seeds!

What Are the Photoperiods of Autoflowers?

When growing autoflowers, you can keep a consistent photoperiod throughout their entire growth cycle. Whether this is 16 hours light, 8 hours dark, 18/6, or 24/0, autoflowers will produce flowers because their growth cycle is not dependent on light. However, like all other strains, you’ll still need to adjust the height of your lamp as the plants grow taller—although they’ll never grow too tall.

AutoFlowers’ Growing Guide

How Long Do You Need to Grow Autoflowers?

Autoflowers are usually much quicker than photoperiod plants, with a lifecycle of about 10 weeks. However, if you’re experienced and have found an especially fast strain, you can grow a plant from seed to fully flowered in 8 weeks.

Autoflowering CannabisAutoflowering cannabis, Grace Genetics 

Do You Need to Do Anything Special for Autoflowers?

Autoflowers do differ from photoperiod cannabis in a few ways and there are a few things you will need to be aware of as you grow:

  • Watering: Autoflowers require less water than photoperiod plants because they are smaller. They also require lighter soil so that excess water can drain quickly—adding clay balls or coco coir can help. If you’re using soil, you’ll want to use a PH meter to test your water/nutrient mix to have a pH of 6—7.
  • Temperature and humidity: Autoflowers like room temperature (~70°F). RH is the same as other strains, but during flowering, it should be between 40—50%.
  • Space: This depends on your growing technique, however on average an autoflowering plant needs about 2-4 gallons of room, depending on the strain and environment you’re in.
  • Grow them alone: Autoflowers grow better when grown next to other autoflowers—you’ll get smaller yields and less reliable growth periods if you grow them next to photoperiod plants.
  • Nutrients: Autoflowers need fewer nutrients than their larger cousins. Be sure to check out the nutrient requirements provided by your seed supplier, but in general, because autoflowers are so much smaller, they need about ½ to ¼ the number of nutrients that a normal-sized plant requires.

Benefits and Drawbacks of Autoflowering

Here’s a quick pro and con guide to autoflowers to help you make your decision about whether they are right for you!

Pros Cons
Fast life cycle Lower yields
Tiny plants/small space requirements Potential lower THC levels
No changes in photoperiods Not easy to clone/clones are poor quality
Fewer nutrient requirements If you make mistakes the plants don’t have time to recover
Generally resilient A smaller variety of strains (but still a fair amount!)
Generally easy to grow and maintain

What is autoflower?

An autoflower, short for autoflowering cannabis, is a type of cannabis plant that automatically transitions from the vegetative stage to the flowering stage based on age rather than changes in light cycles. It offers a convenient and efficient option for growers looking to cultivate cannabis with minimal hassle and maximum flexibility.

Why did autoflower produce seeds?

Hermaphroditism: Cannabis plants can sometimes develop both male and female reproductive organs, a condition known as hermaphroditism. It can happen due to stress factors such as light stress, temperature fluctuations, nutrient imbalances, or physical damage to the plant.

Light Leaks: Autoflowering cannabis plants rely on age rather than light cycles to transition from the vegetative stage to the flowering stage. However, if your grow space experienced light leaks during the dark period, it could have caused stress to the plants.

Genetic Predisposition: While autoflowering strains are typically bred to be stable and resistant to hermaphroditism, there can still be genetic variations within a strain. If your autoflowering plant had a genetic predisposition to hermaphroditism, it may have produced seeds.


Overall, we think autoflowers are an awesome development in cannabis cultivation. They’re extremely unique and easy to grow, they don’t require much maintenance, and you’ll still get decent yields for the size of the plant. Also, you can grow more of them in a 4×4 tent than you could if you were growing larger photoperiod strains. They definitely make life easier if you’re growing your first crop since such a large part of growing becomes automatic.

If you have any questions, please don’t hesitate to reach out to us!

And be sure to check out our other blog posts for useful tips on becoming a great grower!

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