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 and what are the fastest autoflower strains? 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.

Fastest autoflower strains

For those who are in a hurry we have created a top 3 with the fastest growing autoflower strains. Check it out!

  1. Gorilla Glue
  2. Santa Maria
  3. AK 48

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

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

What is the best light scheme for an autoflower grow?

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 keep your autoflower grow 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’s 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 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.

Tip: Check all our high quality autoflowering cannabis seeds