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How long do Autoflowers take from seed to harvest?

25 January 2023
If you're wondering how long it takes for autoflowers to complete their cycle, read this article!
25 January 2023
13 min read
How long do Autoflowers take from seed to harvest?

Read more
  • 1. What are autoflowering cannabis plants?
  • 2. How long does it take for autoflowers from seed to harvest?
  • 2. a. Week 1: seedling stage
  • 2. b. Week 2: early vegetative stage
  • 2. c. Week 3: late vegetative stage
  • 2. d. Week 4: late vegetative stage
  • 2. e. Week 5 - pre-flowering
  • 2. f. Week 6: first half of flowering
  • 2. g. Week 7: first half of flowering
  • 2. h. Week 8: second half of flowering
  • 2. i. Week 9: second half of flowering
  • 2. j. Week 10: end of flowering and ripening
  • 2. k. Week 11: harvest
  • 3. In conclusion

Growing cannabis is like developing a skill over time. It takes time, patience, and you must be prepared for failure along the way. However, despite your urge to maintain a cannabis garden, a lot of factors can go against you. When you realize that it takes almost 4-5 months to harvest the buds (not to mention the extra time for curing) you may change your mind and settle for buds available in the dispensary. But, what if I told you that autoflowers are the solution to your problems? It doesn’t take a lot of effort to grow them, and you save the most important resource – time. Unlike photoperiodic strains that can take anywhere from 8-14 weeks or more, autoflowering strains take as little as 7 weeks up to 11 weeks from seed to harvest. So read on to learn more about autoflowers from seed to harvest.

The advent of autoflowering cannabis cultivars opened up a whole world of new possibilities. The idea that a person could place a seed in the soil and harvest a canopy loaded with flowers in a matter of weeks brought many new growers into the fold. But rapid growing times aren’t only beneficial for impatient growers or those looking to maximize commercial profits. This trait comes in extremely handy for growers looking to remain as stealthy as possible. Cannabis prohibition has caused growers all over the planet to have to adapt and overcome. Autoflowering plants are highly valuable to them because it gives them the opportunity to set up and take down a growing operation in such a small window of time, leaving them with jars packed full of buds at the end of it all. 

So, ask yourself, what are you looking for in a cannabis plant? If you don’t mind waiting several months for a huge plant to grow, develop, and put out buds, then you’ll get on just fine with photoperiod genetics (those that require a seasonal change in the light cycle to trigger flowering). However, if you want delicious and potent buds at your disposal as soon as possible, then you need to sow autoflowering seeds into the soil, my friend! Decades ago, autoflowering strains didn’t really stand out too much. Sure, they grew extremely fast but lacked the potency and productivity of their photoperiod counterparts. Since that time, skilled breeders all over the world have been working hard to produce autoflowering strains that match, and even outcompete, photoperiod strains when it comes to THC content. Newer varieties also offer excellent yields in very small windows of time. Just in case you’re clueless about autoflowers, let’s start with:

1. What Are Autoflowering Cannabis Plants?

Autoflowering cannabis seeds grow just like regular cannabis plants. However, there are a few differences. The biggest difference is that while traditional cannabis plants grow and flower according to the seasons, autoflowers don’t follow seasons. In simple words, they don’t flower according to the light they receive. Another major difference is the time required to grow autos vs traditional cannabis plants. 


How long do autoflowers take from seed to harvest: what are autoflowers?

Autoflowers can take between 7-11 weeks from seed to harvest.

By traditional cannabis plants, we are referring to photoperiod plants. Let’s imagine you plant a regular cannabis seed today. You wait for it to complete its vegetative stage while providing anywhere from 16-18 hours of light. If they are growing outside, it’s out of your control and you can only plant them based on the seasons. Anyway, coming back to the vegetative stage, the plant will grow indefinitely in the vegetative or growth stage until it receives almost 16-18 hours of light. Once the number of hours reduces and it begins to receive only 12-14 hours, the flowering stage is triggered.

With autoflowers, though, it’s different. They don’t follow seasons and are grown under the same light cycle from seed to harvest so you can expect to harvest yields faster.

Without diving too deeply into genetics and evolution, this difference came about via natural selection. Most wildtype and landrace cannabis plants found in nature are photoperiods, with the exception of those that adapted to conditions further north. Natural dispersion and human migration drove cannabis up to northern regions that experience shorter growing seasons. Here, relying on seasonal sunlight as a cue to start flowering wouldn’t leave plants very long to reproduce and set seed. Therefore, naturally occurring autoflowering cannabis plants—known as the subspecies binomial Cannabis ruderalis—developed the ability to flower based on their age to determine their survival and proliferation. Wildtype ruderalis specimens are nothing special when it comes to flower density and cannabinoid and terpene profiles. However, breeders have crossed these genetics with photoperiod varieties to get the best of both worlds. The hybrid progeny have both the autoflowering gene and possess superior phytochemical production.

2. How Long Does It Take For Autoflowers From Seed To Harvest?

So, coming back to the main question… How long does it take for autos? Well, it depends. There’s no exact answer, but there’s an average time that’s good enough to consider. Autos – like regular plants – also spend some time growing in the vegetative stage. With regular plants, you can force them to flower by changing the light schedule.

During this time, plants put all of their energy and resources into putting out large fan leaves. These biological solar panels perform photosynthesis and create more energy and allow plants to form big canopies. Later down the line, in the flowering phase, plants put out flowers on the nodes (the point at which branches meet the mainstem) that they spend time developing during the vegetative phase. Autoflowering strains charge through the veg period much faster. It only takes them around four weeks to go from a tiny sprout into a large plant with a developed root system and canopy. Growers of photoperiod plants have the option to force their plants into flower at this point, too. However, it will involve sacrificing their full potential in the interest of speed.

For instance, if you’re providing an 18/6 light/dark cycle now, you can make the plants flower by switching to a 12/12 cycle.


How long do autoflowers take from seed to harvest: how long does it take?

Autoflowers start flowering automatically around 4-5 weeks since germination.

With autos, however, you can’t do that. Why? Well, it’s because autos follow a fixed timing. As soon as the plant grows for a while, the plant switches to the flowering phase on its own without your interference. And, this is also why most growers prefer autos. There’s zero maintenance and you’ll never have to worry about light leaks.

How long do autos take from seed to harvest? There’s no exact answer, but most autos complete their growing cycles in just a matter of 7-11 weeks, that is the autoflower time from seed to harvest. The total growing time depends on two factors: Genotype and phenotype.

Autoflowering plants possess a genetic code, or genotype, passed down from both of their parents. All of the offspring share a genotype that dictates their growing speed. However, every offspring features some degree of genetic variability, meaning every plant has a slightly different genetic code and therefore total growing time. This varies between cultivars and also between the same plants of the same cultivar, or “strain”. Phenotype refers to how the genotype expresses itself within a particular environment. Favourable temperature, humidity, nutrition, and lighting all impact growing speed to some degree. 


Here’s how it works:

Week 1: Seedling Stage 

Considering that you’ve germinated the seeds successfully, you can plant the seeds in their respective containers. Autos can be transplanted, yes, but leave that to the experts. They will do far better if you do NOT transplant them and instead plant them directly in the containers you’ve chosen. Transplanting any plant causes stress. While vegetating photoperiod varieties have all the time in the world to recover before flowering, autoflowering cultivars are constantly moving towards flowering regardless. Any unnecessary stress can result in stunted or reduced growth that these plants have little time to recover from, resulting in reduced vigor and yields.


How long do autoflowers take from seed to harvest: week 1 - seedling

Bruce Banner Auto on week 1 by Chubbs.

There isn’t a lot of action in the first week, but it will start pretty soon. Additionally, remember not to feed any nutrients during the first week. Sure, you want your plants to grow fast and also want to help them, but feeding nutrients in the very first week will actually burn your plants faster than you can imagine! Although your autoflowering seedlings might seem like they’re cruising along just fine, the slightest wrong move can result in detrimental effects. As well as being careful when it comes to feeding nutrients, you should also be exact with your watering. Always wait until the top couple of centimeters of soil becomes completely dry before watering your seedlings again.

Giving them too much water can over-saturate the growing medium. It might not seem like it, but the soil contains oxygen, and plant roots need this element in order to breathe. Watering seedlings too much can result in root suffocation. On top of this, the anaerobic (oxygenless) environment caused by overwatering can foster pathogens that can kill seedlings in less than a day. These bad microbes cause a disease called damping off that will spell the end of your grow before it truly begins.

Seedlings are extremely fragile so make sure the conditions are on point and that you handle them with care!

Week 2: Early Vegetative Stage 

The plants will show some growth at this point. Use some nutrients, but it will be better if you use it at quarter strength. You can even use a little more but try not to burn the babies. Once the first pair of true leaves have appeared, your plant is officially in the vegetative stage.


How long do autoflowers take from seed to harvest: week 2 - early veg

Bruce Banner Auto on week 2 by Chubbs1 and Hardcorezgarden2.

Remember that cannabis plants depend on the environment to thrive so make sure the conditions are within the acceptable range. During the vegetative stage you should keep the following conditions for the best plant growth possible:


60% RH22-28°C

Week 3: Late Vegetative Stage 

The plant starts growing vigorously this week because the roots have properly developed. By now your plant should be growing exponentially so you should be providing enough nitrogen.


How long do autoflowers take from seed to harvest: week 3 - late veg

Autoflower on week 3 by hardcoresgarden1 and nebula4202.

Also make sure that you provide a little bit of phosphorus, potassium, and micronutrients to allow your plant to develop foliage, stems, and branches as it should, and adjust the lights accordingly so you don’t burn the plants. You can use full-strength nutrients at this point. Adjust the lights accordingly so you don’t burn the plants. 

Week 4: Late Vegetative Stage

The plant is a month old now. It will grow faster than you can control it. Thus, it makes sense to train them using several techniques. The best technique by far is Low-Stress Training (LST) but you can also top the tips to produce several colas. 


How long do autoflowers take from seed to harvest: week 4 - late veg

Autoflower on week 4 by Chubbs.

Autoflowers respond very well to both FIMing and Topping if done properly, so make sure that you don’t do it too aggressively! Depending on how your plant grows (and if needed), it’s a good idea to provide support with a trellis net or bamboo stakes so you keep your plants in the upright position it doesn’t fall over.

Week 5 - Pre-Flowering

If everything went well your plant should be ready to enter the pre-flowering stage. Some plants will start showing pistils at this point but others will just show signs that they’re about to enter pre-flower, such as the flowering sites turning light-green. The pre-flowering stage happens any time from week 4 to 5. Some may not, but they are super close.

When dealing with non-feminized genetics, growers have to carefully sex their plants as soon as possible during pre-flowering. Those that show signs of male flowers are immediately removed to prevent pollination that would send female flowers to seed. Thankfully, feminized genetics are made possible by “selfing” the parent specimen. The result? Plants that only emerge as females. This saves casual home growers a lot of work during this crucial stage of the growing cycle. 


How long do autoflowers take from seed to harvest: week 5 - pre-flower

Cream Cookies Auto by Nebula420.

If this is the case, you should switch to flowering nutrients if the plants are responding positively after receiving nutrients all this while.

Week 6: First Half of Flowering 

Once your plants have grown a good amount of white hairs, they’re in the proper flowering phase now. During this stage you should add nutrients that include a lot more potassium and phosphorous compared to nitrogen. Depending on the specific strain you’re growing, it’s possible that your plants start stretching a lot so you will have to adjust the lights so that the stretching doesn’t go out of control.


How long do autoflowers take from seed to harvest: week 6 - first half of flowering

Autoflower on week 6 by Nebula420.

Just like in the other growth stages, you should adjust the conditions; During the first half of the flowering stage the humidity and temperature should be the following:


40-50% RH20-26°C


The conditions mentioned in the table aren’t obligatory, you will still be able to grow and enjoy your harvest but following these conditions will result in the best harvest possible because these conditions allow your plants to perform their basic processes such as photosynthesis and transpiration as they should.

Lemon AK Auto
5 out of 5
She was very easy. She grew quite chunky considering she's a sativa, but the effects did feel sativa. She has a lovely taste.
Verified customer
Reviewed 19 January 2020

Week 7: First Half of Flowering

By week 7 your plant should be starting to fatten up the buds so you’ll see proper buds now. Obviously, they won’t be very big but will start to take form, you’ll also see pistils keep shooting everywhere, and adding nutrients will increase the rate of growth.


How long do autoflowers take from seed to harvest: week 7 - first half of flowering

Autoflower on week 7 by Chubbs.

Stretching will also stop now since the plant focuses all its energy on the flowers so there’s no need to worry about space now, just make sure your plant gets the nutrients it needs and the conditions are on point. Despite seeming ready, your plant needs at least 2-3 weeks so be patient, if the flowers look good now imagine how they’ll be when they’re actually ready!

Week 8: Second Half of Flowering

Week 8 marks the second half of the flowering stage, this means that the buds will become fatter and denser during week 8. Make sure you don’t try to use any training techniques at this point since the plant has already come too far and you may end up stressing it.


How long do autoflowers take from seed to harvest: week 8 - second half of flowering

Autoflower on week 8 by Chubbs.

Even if your plant has already developed too many amber pistils just let it be; Some strains get amber pistils before it’s time to harvest and it’s completely normal, the standard practice for harvesting is to see the color of the trichomes, so keep an eye on the color of the pistils at all times. Remember that for the second half of flowering the conditions should be the following:


30-40% RH18-24°C


These growing conditions will ensure your buds fatten up as they should and that they don’t have a lot of water in them, which will result in better yields after drying so, if possible, make sure the humidity and temperature are within the ranges mentioned in the table above.

Week 9: Second Half of Flowering

The second half of the flowering stage marks the week before the last, by now the majority of the hairs that were once white should be orange or brown and there should be lots and lots of trichomes all over the buds and surrounding foliage. If everything goes as it should, you can stop feeding nutrients at this point.


How long do autoflowers take from seed to harvest: week 9 - second half of flowering

Week 9 of flower by Wachsemilian.

You can even start flushing to remove extra chemicals. There’s no need to flush if you’re growing organically though. The buds will display a mix of clear and white trichomes. Some plants may be slow and you may not see cloudy trichomes at all. If that’s the case there’s no need to worry, this depends from strain to strain, you’ll see the trichomes changing colors once it’s time.

Week 10: End of Flowering and Ripening

On week 10 the trichomes change colors from clear to cloudy and sometimes to amber. You’ll also notice the fan leaves turning yellow. You can flush again this week. Flush as much as you can to remove all the chemicals.


How long do autoflowers take from seed to harvest: week 10 - end of flower and ripening

Checking the state of the trichome sis the standard practice to know when to harvest.

Flushing is also done to make the buds taste better when you smoke them, so don’t skip this part. Once you have finished flushing, your plant is ready for harvest.

Week 11: Harvest

Most growers harvest their autoflowers during week 11. You’ll notice that the pistils are a lot more red and amber in color compared to white pistils. Also, the majority of the trichomes should be cloudy and a good amount starting to turn amber.


Wedding Cheesecake auto time-lapse from seed to harvest.

If you have a jewelers loupe or a microscope, wait until at least 70 percent of the trichomes are cloudy. If you see too many clear trichomes, you need to wait a couple more days until they’re cloudy. And remember, after harvesting your plants, you will still have to do the following:

These processes can be done in several ways but they should be done if you want to have the best results possible; These processes will not only make your buds smoke better but will also result in better tasting and smelling buds!

LSD25 Auto
4 out of 5
I think my mistake was to decide not to train her. She was basically one fat cola and very short side branches with small buds.
Verified customer
Reviewed 21 October 2022

3. In Conclusion

As you can see, it takes about 10-11 weeks for an autoflower to complete its entire life cycle. Some autoflower seed to harvest time may take a week more or you might even harvest them a little earlier, but it all depends on the type of container, nutrients, light schedule, and type of lighting you’ve used. Even commercial growers can harvest their amazing plants just after week 11. However, some growers prefer to harvest only during weeks 12-13 so that most of the pistils turn amber. Buds that are amber produce a body-high similar to an Indica, so you can keep this in mind before you cut down the buds. 

So, as you can see, it takes about 11 weeks for an autoflower from seed to harvest! You may require a week more or less, but this is an average estimate for an autoflower seed to harvest cycle.