Cannabis cycle: here are all the growth phases of the plant

Cannabis cycle: here are all the growth phases of the plant

Modified on: 19/04/2024


Growing cannabis is not a simple process. To do so, in countries where it is permitted by law (remember that Switzerland – JustBob’s HQ – has law, which allows the purchase of CBD cannabis with a THC of less than 1%). It is essential to be aware of the 4 main stages of growth: germination of the seed, the seedling or seedling stage, the vegetative stage and finally, the flowering stage.

These stages can be subdivided into other intermediate steps, limiting ourselves to these four for simplicity.

Cannabis cycle in four stages      

  • seed germination: 2-10 days
  • seedling or seedling stage: 1-3 weeks
  • vegetative stage: 1-15 weeks
  • flowering: 7-14 weeks

The growth cycle and its duration can vary depending on the seed you choose (e.g., autoflowering seeds or feminised seeds) and where you decide to grow them, indoors or outdoors.

A good quality marijuana seed can be recognised firstly by its colour (usually light-brown or dark brown with tiger stripes) and if it feels complex and compact to the touch.

This article will explain the best methods for growing a cannabis plant correctly.


Seed germination

Seed germination is the period from when the seed is planted in the soil until the first leaves, called cotyledons, sprout. These ‘baby’ leaves do not have the familiar serrated shape, but don’t worry: the leaves will gradually take on the appropriate shape.

For hemp Sativa seeds or any other species to germinate, conditions must be humid: temperatures between 22° C and 25° C is considered optimal. The seed shell must be softened and allowed to grow in the dark, like inside a cupboard. A little water will be sufficient nourishment. Once the cotyledons have sprouted, the growth process has officially begun, and the sprout can be exposed to light.

It is significant to be patient and not speed up the germination process because you risk killing the plant before it even grows.

Read also: THC & brain: short and long term effects and damage

The seedling or seedling stage

If you have decided to germinate the plant in a moist cotton pad (the so-called ‘moist cotton pad method’), you will need to transplant the seedling.

Many growers prefer to use a large pot straight away to avoid repeated transplanting as the plant grows. The seedling does not need as much water compared to the previous cycle.

If you decide to buy a particular type of low-fertilised, pH-stable soil online, there will be enough nutrients for the two weeks after the germination phase.

Meanwhile, the leaves will develop more and more tips, starting at 3, 5, 7 and so on. From this stage onwards, the choice of light is crucial. Most experts recommend a PPFD level of 200-400, while others prefer T5 fluorescent tubes. As in the germination phase, a temperature of 20-25° C is advisable.

The vegetative phase

The plant will grow branches, leaves, and roots in this phase. More water, fertiliser and light will then be required.

For the latter, the level used in the previous phase can be increased, and consequently, also, the number of hours of exposure is between 18 and 24.

The period during which the plant is vegetative can vary: on average, we are talking about 4 to 6 weeks, with a maximum of 15. Furthermore, the length of the vegetative phase must depend on the size of the grow room: remember that a cannabis plant can be up to 7 metres tall!

the flowering phase

The flowering phase

With autoflowering seeds, the flowering phase of Cannabis flowers or CBD flowers will follow the vegetative stage automatically. If the plant is indoors, the light hours should be reduced to 12; if outdoors, the plants themselves will feel the shortening of the days as autumn approaches, even if grown in the equatorial zone. As a result, more water, phosphorus, and potassium will be needed as the plant flowers.

Once the flowers are heavier and produce more resin, they are ready for harvest, although some growers wait a few weeks to enjoy a more generous crop! The flowering phase lasts an average of 7-14 weeks, which varies according to the type you’re growing and your personal preferences.

You can also speed up the flowering process by exposing the plant to darkness for 48 hours before the 12/12 light cycle and then switching to an 11/13 cycle. In this way, the plant will believe that winter has arrived.

Read also: THC-free cannabis: are there really 0% THC levels?


In conclusion, we can say that there is no magic formula for growing a cannabis plant correctly because several factors that contribute to its growth have already been mentioned.

This article has limited itself to explaining the stages of growth of the cannabis plant while reminding you that this process should only be practised where it is permitted and does not violate the law.

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