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growing autoflowering cannabis seeds indoors

-Limited Strains
If you were hoping to get an autoflowering seed that contains the genes of your favorite strain than you will be disappointed to learn that the number of strains available with this feature is few and far between. If you are open to trying new strains than this isn’t so important but for those wanting to grow a specific plant for its individual qualities than autoflowering seeds likely may not be an option.

Indoor autoflower grow gu >Published Mar 11, 2019 10:38 a.m. ET

Autoflowering, sure you have likely heard of it, but what does it mean? Autoflowering cannabis strains will automatically adjust from the vegetative stage to the flowering stage with absolutely no changes in lighting. This makes them appealing to growers looking for a foolproof seed that requires the least work. Autoflowering cannabis strains will also be ready to harvest early usually in as little as 60 days after they are started from seed.

Autoflowering grow cycle

The autoflowering grow cycle differs from any other cannabis plant due to its hastened finish meaning shorter stages and fewer adjustments required for lighting. There are three different stages in the life cycle of an autofloweringplant.

Post germination 8-12 weeks – The first stage in an autoflowering grow cycle lasts approximately 8-12 weeks. This is how long it takes the cannabis plant to fully establish itself before entering into the vegetative stage. Autoflowering plants should not be transplanted after this part of the cycle. Once seeds crack open and plant life begins it is necessary to provide sufficient lighting. While autoflowering cannabis strains can live on a bare minimum of only 5-7 hours of daylight per day, it is recommended to provide at least 18 hours. Some growers swear by 24 hours a day of light so if you don’t have a timer then don’t worry too much. You will just want to place your light fixture several inches further from the plant’s foliage to be sure nothing gets burned.

Vegetative Stage 10-14 weeks – This stage of an autoflowering grow cycle is much more accelerated then their more traditional counterparts. Autoflowering plants will exit this stage within 30 days and begin blooming. The autoflowering plants will stretch out the most during this stage with most easily growing an inch or more in a day. To see the most effective results and speed this process up each plant should be grown in its own 10 liters to 20-liter pot and should be kept at a temperature of 25 degrees Celsius with a high humidity level of around 60%-70%. In the vegetative stage fertilizers and nutrients are essential. Adding nutrients along with constant adjustments of your lighting to avoid burning while the plant is skyrocketing in size are the two most significant requirement changes during this phase of the cycle. Expect massive growth and leave plenty of room at least ten inches between the plant’s foliage and any bulbs.

Flowering stage 12- 20 weeks – Autoflowering plants will take 45-60 days from when the first pistils and hair begin to appear to when the plant will be ready to harvest. The optimal temperature for autofloweringcannabis to flourish at this stage is 25 degrees Celsius with a humidity of 45%-55%. Lighting schedules will not need to be adjusted at all and will maintain the same as when you began. Fertilizer can be provided up until the last two weeks before harvest which is when flushingshould occur to ensure the bud is safe for ingestion once harvested.

Tips for growing autoflowering plants

  • Provide the most lighting possible.
  • Keep a safe distance between lights and plant foliage to prevent burning.
  • Grow indoors for optimal results.
  • Water frequently. Since an autoflowering cannabis strain grows so quickly, it will need a bit more water to do so. Misting is a great way to add extra water to your care regimen without risking root rot.
  • Use 20 liter or larger pots. An autoflowering plant requires space to stretch out its roots to establish its immune system. Insufficient room to grow will hinder the pace at which the plant grows and overall yield that will be produced.
  • Prune and train just like you would with any other marijuana plant. Autoflowering strains grow much faster during the vegetative stage making them perfect for growing methods such as the scrog method. The plant can recover faster making it hardy for those who want to manipulate the size of the buds or plant itself.

Pros and cons of using autoflowering cannabis


Rapid Growth
Autoflowering strains can cut as much of half of the expected grow time necessary when compared to their alternatives.

Smaller, More Compact Plants
Growers who only have a small space in which to grow will benefit significantly from an autoflowering strain. Since their overall life cycle is shorter, they do not usually end up as tall. The average autoflowering plant will reach a maximum of 1.5 feet tall.

Powerful Genetics
Autoflowering cannabis seeds are made by breeding hand picked strains specifically for qualities that include hardiness. The majority of DNA used in the making of autoflowering plants is from those grown in the northern hemisphere that have a much shorter growing period and much cooler temperatures making them easy to care for.

Fast Harvest
Autoflowering plants have a life cycle that lasts only a couple of months making them perfect for those wanting to pull off multiple yields each year with minimal effort and time.

Do Not Require Adjustment of Lighting
Autoflowering plants can get by on as little as five hours of daylight but prefer 18+ hours and can even do well in full 24 hours a day. This makes them useful for those who don’t want to have to keep track of an ever-changing light schedule.


The size of an autoflowering cannabis plant can be both a positive and a negative feature. A smaller plant quite often translates to a lower yield. Since an autoflowering plant doesn’t grow as long, it will not grow as high. This is not always the case as some choose autoflowering seeds for specific growing methods such as SCROG which can easily manipulate a small plant into producing plenty of giant buds that are short but bountiful.

Autoflowering seeds require more light than your average marijuana plant which can be costly when considering the unavoidable spike in utility bills from running lights so frequently.

-Low THC Content
Autoflowering seeds are created using more northerly strains of marijuana. Unfortunately, the majority of these strains are not high producers of THC. This does not mean that you cannot have a high THC content autoflowering strain, it just means that the majority of autoflowering plants will be lower on average than most other non-autoflowering ones.

-Limited Strains
If you were hoping to get an autoflowering seed that contains the genes of your favorite strain than you will be disappointed to learn that the number of strains available with this feature is few and far between. If you are open to trying new strains than this isn’t so important but for those wanting to grow a specific plant for its individual qualities than autoflowering seeds likely may not be an option.

-Difficult to Transplant
Since autoflowering cannabis has such a short life cycle, just one small interruption in its focus can be enough to seriously hinder its health. Transplanting should never be done beyond the first couple of weeks after germination if you don’t want to severely stunt your plant’s growth. This makes autoflowering plants unless for those who wish to begin by growing indoors to later transplant and finish them outside.

  • More Expensive/ More Difficult to Obtain
    Despite some of the downfalls of autoflowering seeds, they have grown in popularity making some of them a bit more expensive to purchase. Since the strains available with this feature aren’t exactly common, many seed banks don’t carry or advertise them as they aren’t the biggest money makers.

In conclusion, autoflowering cannabis strains are neither better or worse than their counterparts and are more of a group of specific features that focus around a shorter time requirement before harvest. To know if growing one is right for you weighing the pros and cons alongside your particular needs and preferences to see if an autoflowering plant will provide you with the product you hope to achieve.

Because in most cases autoflowers become a lot smaller and spend a shorter vegetative phase than photoperiod species, they also need considerably less nutrition so please don’t overfeed your plants. When you use the aforementioned soil it won’t be necessary to add extra nutrition.

How to grow autoflowers?

Autoflowers are a great choice for both beginners and advanced growers. An automatic flowering plant is in fact easy to grow and you don’t need much for a successful breeding. Moreover, the new generation of autoflowers are increasingly producing weed and above all of high quality. But how to grow autoflowers? How long does it take to grow an autoflower? What do you need to grow autoflowers indoors or outdoors? What is the best light scheme and what is the easiest way? In this blog you will find all the answers to your questions and we provide various tips for a successful breeding.

How long does it take to grow an autoflower?

A big advantage of an autoflower is the speed. Nowadays it takes on average 8 – 12 weeks for an autoflower to become ready for harvest. This allows outdoor growers to harvest 4 to 6 times a year.

Two ways to grow autoflowers

Just like normal cannabis seeds, autoflowers can be grown in two ways: indoors or outdoors. Which method you choose is of course entirely up to you and the available options, but before you make a choice it’s important to know what the benefits are from a indoor and outdoor cultivation.

Advantages: growing autoflowers indoors

  • Speed: in an average of 10 to 12 weeks from seed to harvest.
  • Autoflowers are suitable for growing in confined spaces.
  • You can grow without changing the light scheme.
  • Autoflowers can receive a lot of light and as many know: light is weight.
  • Due to a controlled interior space, the risk of top rot is small.

Advantages: growing autoflowers outside

  • Due to the compact size, an autoflower is less noticeable.
  • You can harvest multiple times in one summer (2 to 4 times per summer).
  • If you grow in late spring and summer, the chance of rot or fungus is very small.


Autoflowers can be grown outdoors as long as the temperature is above 15 degrees. This is in particular an important point of attention for growers in the UK who want to grow outdoors.

How to grow autoflowers indoors?

Autoflowers are very suitable choice for indoor cultivation. For example in a closer or small tent. However, there are a number of points of interest that apply. Besides, for a successful breeding it’s important to make good preparation. Of course you will need autoflowering cannabis seeds, but there is more. Below you find a step by step explanation on what you should pay attention to.

Pots and earth

Because autoflowers grow quickly and often flower after 30 days you have little time for repotting. It’s therefore advisable to place the germinated seeds directly in the final pot with a lightly fertilized, well-aerated growth medium. Think of earth mix or coconut. Air pots are the most suitable, but dark pots of 10 – 20 liters with drainage are also perfect.


Because in most cases autoflowers become a lot smaller and spend a shorter vegetative phase than photoperiod species, they also need considerably less nutrition so please don’t overfeed your plants. When you use the aforementioned soil it won’t be necessary to add extra nutrition.

Humidity and temperature

An autoflower grows and blooms best at a temperature of 20-25 °C and a humidity of 50-70%.

Note: prevent the temperature from exceeding 28 °C degrees.


For growing an autoflower you have various options with regard to lighting. Think of LED, CFL, HPS or MH lamps.

Note: When the lamp is too close to the plant, leaves will burn. Because autoflowers often grow at a fast pace, you will have to keep an eye on your lights every day.

What is the best light scheme for an autoflower?

Autoflowers don’t need much light to survive. Indoor growers can light their autoflower with about 5 hours a day, but that is of course not enough for a good yield. For a good yield you need approximately 18 to 20 hours of light per day. That is why indoor growers mostly apply a 20/4 light scheme during their breeding. That means 20 hours of light and 4 hours of dark.

How to grow autoflowers outdoors?

Many people wonder: can autoflowers be grown outdoors, for example in the garden, in the wild or on a balcony? The answer to that is, yes! In fact, autoflowers are very suitable for outdoor growing in both warm and cool climates. Mainly because the plant gets more light outdoors which benefits the trichome production. Moreover, the CO2 ensures a rapid metabolism, so that the plant is able to grow faster. Below you can read how autoflowers should be grown outdoors.

Best time to plant autoflowering seeds outdoors

Outdoor growers can start when the spring begins and continue growing until fall. For many climates, the hottest periods are between March and September / October. It is important that the outside temperature is at least 15 degrees. Timing is very important. Remember that.

If you live in a country with a warm climate (6 – 8 months of summer) then you are lucky. You can then harvest 3 to 4 times. However, if you have a summer of 4 – 5 months you can harvest 2 – 3 times.

What should you pay attention to?

For outdoor growing, it’s important to germinate the seeds indoors and place them under artificial light for about two weeks before being moved outside. That way the seedling can strengthen and you prevent a young seedling from breaking through a strong gust of wind or being eaten by animals.

Note: when you plant the seeds at the end of the season or when the weather is unreliable, you can consider growing in a greenhouse. The risk of top rot will then be greatly reduced. Also, do not plant the seeds early because cold can damage your plant and reduce your yield.


In our opinion it is best to grow your autoflower as organic as possible. For example, by mixing the potting soil with organic fertilizers and nutrients such as cow and chicken manure, compost, bat guano, blood meal or permite.

Such a mixed soil is more than sufficient to provide the autoflower with nutrients throughout the entire process of growing and flowering. When you see a sign of a lack of nutrients, for example because the leaves turn yellow, it’is always possible to add some extra nutrients.

Pollen and seed production

Growing outdoors always involves a risk. Your female plant can easily be pollinated by a male plant, making your harvest less big. Such a pollination can even happen when the male plant is miles away. A smaller harvest is disadvantageous for many growers, but can also offer opportunities. Pollinated plants will produce seeds that you can use for your next harvest.

Although pollination is quite difficult to prevent you can take measures to reduce the chance of pollination. For example, by placing a high fence.

Mold, insects, animals

Finally you have to take mold, insects and animals into account. Especially because they pose a threat to your plant. You can take precautions by digging wire mesh under the roots and making a fence of chicken wire. However, you cannot do much against fungi and insects. Fortunately, rain and wind often prevent insects such as aphids and spider mites from starting a colony on your plant.

What do you need to grow autoflowering weed outdoors?

One of the most important factors for the cultivation of autoflowers outdoors is the soil. For firm buds you need a decent soil. This can be in your own garden, but of course also in the wild (also called a guerrilla culture). As long as the soil is fertile, beautiful autoflowers can grow on it. You also need sunlight, a little rain and a breeze from the wind. Once you have found the right place, you can get started. For your outdoor grow you have basically two options:

  • Directly in the ground
  • Grow outside in a pot

Growing autoflowers directly in the ground

Unfortunately, inexperienced growers often opt for the least effective method by placing the seed directly in the ground. This is a big gamble. Especially because the conditions for germination and seedling phase aren’t optimal.

Growing autoflowers outdoors in a pot

A better option is to carry out the germination process and the seedling phase indoors after which the pot is moved outside after just 2 weeks. With this method, the chances of success are much greater. Especially because the most vulnerable process is completed indoors. You can complete this process in two ways:

  1. For the germination and first part of the seedling phase you can use a starting pot after which you place your seedlink to the final pot with the same medium. This is also called repotting. However, autoflowers don’t like this process. So be careful because root damage will not improve the quality of your plant.
  2. Place the germinated seed directly in the final pot with a nutritious soil. This makes your plant powerful.

Tip: you can avoid the transplant shock and give the roots the chance to grow further by burying the pot in the ground. To do this, cut the plastic tray loose, place the soil with the plant in the ground and make sure you use the same type of soil as the soil in the pot.