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Autoflowering Cannabis Seeds start to flower automatically when they reach a given maturity, regardless of photoperiod.

Auto flowering cannabis seeds are in almost all cases crossings (hybrids) between Cannabis ruderalis and Cannabis indica and/or Cannabis sativa. As said before, they start to flower automatically, this in comparison to the ‘classic’ Cannabis sativa and Cannabis indica which need a reduction of sun hours a day in order to flower. Auto flowering marijuana seeds with Cannabis ruderalis inheritance simply start to flower when they reach a certain age. Most autoflowering cannabis seeds start to flower around week 3.

Autoflowering cannabis seeds are already on the market for a while, but in the last few years the popularity of autoflowering seeds has skyrocketed. And totally deserved in our humble opinion.

Advantages Of Autoflowering Cannabis Seeds:

– Multiple harvests per year
Autoflowering cannabis seeds will always flower automatically, this means that if you start early in the year, you can all of a sudden harvest your plants in the middle of the summer. This will enable you to start a new cycle again. If you have a very favourable spring and summer this could enable some growers to harvest three times a year! Let us compare this to the Cannabis sativa and Cannabis indica. Naturally, sativa’s and indica’s will grow in the spring and summer, and will only flower when the daylight hours are diminishing. This is around the end of summer. This will allow for only one harvest a year, since you are dependent on the time of the year.

– They stay small
The genetics of  autoflowering cannabis seeds will generally keep these plants on the smaller side. Sometimes they are even called ‘dwarf cannabis plants’. The largest benefit of this is that the autoflowering cannabis seeds are very suitable for small cultivation on balconies and smaller gardens. It’s even possible to get some nice results on a window sill! So all in all, perfect for the discreet guerrilla grower…

– Very short growth- and flower period
Autoflowering cannabis seeds grow extremely fast and have a very short flowering period. Most autoflowering cannabis seeds available allow you to harvest within a period of 60-70 days. That’s from germination to harvest!

– Resistant plants
Due to the influence of the Cannabis ruderalis most autoflowering cannabis seeds are reasonably to well resistant to many diseases and moulds. They are also usually quite resistant to the cold.

How To Grow Autoflowering Cannabis Seeds

Growing autoflowering cannabis seeds does not differ greatly from growing the usual Cannabis sativa and Cannabis indica varieties. However, there are a few differences you will need to take into account.

Of course, most notably the life cycle of the plants are very different. Most autoflowering cannabis seeds will flower automatically after 17-20 days of growth, which makes them ready to harvest after 60-65 days, some up to 70-80 days. This in contrast with the sativas and indicas who need the entire spring and large part of the summer to grow, plus a flowering period of 6-12 weeks when the light is weaning.

There are of course certain circumstances which will allow autoflowering cannabis seeds to develop in the best way possible.


Hours of light

On the internet there are many different opinion on this matter, varying from 16 to 24 hours of light each day. We favour 18 hours a day. So from the beginning to the end of the life cycle it’s 18/6.


Autoflowering cannabis seeds enjoy airy soil, relatively low on nutrients. Standard pot plant soil is not suitable for autoflowering cannabis seeds (actually, not for sativa’s and indica’s either, by the way…). It’s much better to buy your soil at a specialized growshop. Always go for the ´Light´ mix.

If you want or need to mix your own soil, you could start with a simple basic recipe such as:

  • 3 parts compost
  • 3 parts peat moss
  • 2 part perlite, pre-wet
  • 1 part vermiculite, pre-wet


During the first 12-14 days you won’t have to feed your plant anything but water. After this period you could start adding growth nutrients, the light type. Continue this until the plant has been flowering for a week. This will amount to about two weeks of giving growth nutrients. Flush well and then switch to flowering nutrients for about 4 weeks. Again, use the light type. About a week before harvesting you can stop giving nutrients.

And please remember, don’t feed them too much. Commercial producers of plant nutrients tend to advise very high concentrations of nutrients for your plants. We usually use a lot less, especially with autoflowering cannabis strains. If the bottle reads 20-30 ml per litre, we will use 10-20 ml per litre.

Size Of Pots

Most autoflowering cannabis seeds will not become very large. So really large pots are not advised to use. You could use pots varying in content from 3 – 15 litre. The larger the pot is you use, the more roots the plant will make, the higher and larger your plant will be. Of course there’s a limit there. In our experience with most autoflowering cannabis seeds 15 litres pots are the limit. Every extra space it gets is basically useless. It doesn’t harm your plants either by the way.


The outdoor grower is of course dependent on the time of the year. With autoflowering cannabis seeds you can start the germination when the first serious signs of  ´nice weather´ have come in spring. Of course it’s important to take into account where you are situated, on this globe. In the warmer regions you could start early may. But if you live in a colder area you will need to wait a few weeks. During a long and warm summer you are able to start a new cycle of plants in the start of august. 2 to 3 cultivations are possible within one season!

In the somewhat colder regions it’s most likely your autoflowering cannabis plants will need a few days more to fully mature than the amount of days given by the seed producer.

P.S. There are areas on this globe were during the summer the sun doesn’t set at all, giving (nearly) 24 hours of daylight. The introduction of autoflowering cannabis seeds has enabled people in these areas to grow outdoors nowadays! From Finland to the North West Territories… Just give ´m a little bit of sun and they will thrive everywhere.

All info listed above is of course strain dependent, and as such could vary.