The Life cycle of Cannabis: From seed to harvest

A sprouting seed, a seedling and a cannabis plant

Cannabis passes through a series of stages in its life. The most important of these are the germination, seedling, growth and flowering stages. Each stage brings its own challenges. Novice growers need to be aware of these, to be sure of giving their plants the attention and care that they deserve.

Plants are living beings. They are at the base of the evolutionary tree, they heal our bodies and souls, they delight our senses. I think all our readers know by now which is our favourite plant: Cannabis sativa L. – a fantastic crop and medicinal plant, and one of the oldest plant genera in the world.

No matter why cannabis is being cultivated, to see with your own eyes how a small seed grows into a bulky plant, which then starts flowering, is a moving experience every time.

Cannabis is an annual plant, so its entire lifecycle takes place within a single year, with most varieties reaching the end of their life after between four and ten months. In general terms, the following four stages of life can be distinguished:

  • Germination stage
  • Seedling stage
  • Growth or vegetation stage
  • Flowering stage

A quick glance is usually enough to determine the current stage. Over time, it is not just the appearance of the plant that changes, its needs also change. Different stages require different quantities of light, water and nutrients. Furthermore, if you want to determine the sex of the plant or prune it, it is useful to know which stage the plant has currently reached.

1 – Germination stage (1 to 2 weeks)

Sprouting cannabis seeds

All forms of life start from a seed of some kind. High-quality seed is the single most important factor for successful cultivation. Cannabis seeds should be hard, dry and brownish in colour. There are a number of different ways of getting the seeds to germinate. The easiest is the paper towel method.

In the germination process, the germ in the seed breaks through its shell and forms a root, which is known as the taproot. Germination takes anything from 24 hours to 7 days. Generally cannabis varieties with a high proportion of Indica germinate faster than pure Sativas.

The germinated seed can now be placed carefully into the growing medium. The plant will start to grow and force its way upwards.

While the first two cotyledons (seed leaves) are being formed, the plant shrugs off the protective seed husk. That signifies the end of the germination stage.

2 – Seedling stage (2 to 4 weeks)

A cannabis seedling growing from the ground

Particular care is necessary at this stage in the lifecycle. Seedlings are susceptible to illnesses and mould. Many novices get carried away with watering and give the seedlings too much fertiliser. Even if you plan to grow outdoors, it may be useful to give the plants a healthy start indoors, assuming that a location is available with adequate light (e.g. a windowsill). The plants need as much light as possible at this stage.

How long the seedling stage lasts depends on the variety and on the environmental conditions. The main focus of the plant is on developing a root system. This forms the foundation for its later growth.

Meanwhile the plant will grow its first “real” leaves with the characteristic marijuana shape.

The leaflets are long and jagged. Initially a leaf has just one leaflet, although a mature cannabis plant will have five to seven leaflets per leaf.

Once the plant produces the full count of leaflets for each new leaf, the seedling stage is over.

3 – Growth stage or vegetation stage (2 to 8 weeks)

Cannabis plants in pots against white background in grow space

Now the plant starts its main growing phase. Provided it receives enough light, it can grow up to two inches (5 cm) in a single day. It is obvious that the plant needs to be repotted if it is still growing in a small pot.

Leafy plants like a healthy soil that is rich in nutrients. The production of chlorophyll and proteins depends on a supply of nitrogen. It is worth investing in the right kinds of fertiliser or even producing them yourself.

As it grows, the plant also needs more water. Young plants are best watered close to their stem, but later on water should be distributed more widely so that the tips of the roots can absorb water more efficiently.

Have you ever heard of topping, super-cropping or lollipopping? Using these techniques you can train cannabis or manipulate the shape of the plant. Growers use them to develop stronger plants with more buds. Opinions vary, however, on whether these techniques actually deliver results. They are only necessary for special cultivation methods such as the Screen of Green (SCROG).

How long the growth phase lasts is not a simple question to answer. Autoflowering cannabis varieties move automatically on to the flowering stage within 2 or 3 weeks. Regular or feminised varieties only start flowering once the days become shorter (outdoor cultivation) or the grower reduces the lighting period to 12 hours (indoor cultivation).

4 – Flowering stage (4 to 12 weeks)

Flowering cannabis plants

For most people, the flowering stage is the most exciting stage in the lifecycle of a cannabis plant. Once the days become shorter and the plant receives less light, it starts to take care of reproduction.

Only now can the sex be determined with any certainty. While male plants produce pollen, the female plants pour their energy into producing flowers or buds. Most growers want to prevent their female plants from getting pollinated, because then they start to produce seeds. That is why male plants should be removed from the growing area.

Some growers use special fertilisers during this stage to stimulate bud formation. During the flowering season, cannabis plants need plenty of water. They may need to be staked to help support the weight of the buds. In order to avoid disrupting hormone development, the plants should not be pruned after the second week of the flowering stage.

The length of the flowering stage again depends on the varieties being grown. Autoflowering cannabis can be ready to harvest within as little as one month, while Indicas need about 6 to 8 weeks. For some Sativa varieties it can take longer than 3 months for the right harvest moment to arrive.

  • Disclaimer:
    Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.


20 thoughts on “The Life cycle of Cannabis: From seed to harvest”

  1. So wait, itll grow for (example) 6-8 weeks, then start to flower, and stay flowering for another 6-8?

    1. Mark - Sensi Seeds

      Hey Toby,

      Thank you for your question,
      Cannabis is an annual plant, so its entire lifecycle takes place within a single year, with most varieties reaching the end of their life after between four and ten months.
      In general terms, the following four stages of life can be distinguished:

      Germination stage – 1-2 weeks
      Seedling stage – 2-4 weeks
      Growth or vegetation stage – 2-8 weeks
      Flowering stage – 4-12 weeks

      I hope this has helped!
      To learn a little more about medicinal cannabis, here are some links that you might find of interest – The life cycle of cannabis: From seed to harvest and When can seedlings be put under lights or in the sun

      Thanks again, and I hope you continue to enjoy the blog.


  2. Questo articolo è molto utile per chi si avvia ad una coltivazione da principiante, manca solo alla fine una buona descrizione per capire quando è ora di fare il raccolto, si può lasciare che la pianta prosegua fino alla morte naturale ? cè un modo per capire quando estrarre la pianta dal terreno per metterla ad essiccare ?

    1. Mark - Sensi Seeds

      Buongiorno Aldo,

      Grazie per il tuo commento, e il supporto dall’Italia!

      Fortunatamente, abbiamo un articolo su How to Harvest Cannabis Plants. Purtroppo però, è disponibile solo in inglese, spagnolo, francese e olandese.

      Una tecnica utile è quella di valutare la percentuale di peli bianchi che hanno cambiato colore (di solito in un marrone-arancione, anche se alcuni ceppi possono avere peli rosati o violacei). Le piante non dovrebbero essere raccolte finché almeno il 40% dei peli non sono diventati colorati.

      I livelli di THC sono spesso più alti se si raccoglie quando il 40-70% dei peli è cambiato; se si continua ad aspettare oltre questo punto, il THC inizierà a degradarsi in CBN. Questo può far sì che l’effetto dei fiori finiti sia più calmante e meno propenso a indurre ansia. Questo processo di degradazione del THC in CBN avviene anche dopo la raccolta e durante la decarbossilazione.

      Grazie ancora per il tuo commento, e spero che tu continui a goderti il blog!

      Buona giornata!


  3. Is possible know the pwrfect ec e ph for the grow and floration
    Of Norther lights n5 x haze???

    1. Scarlet Palmer - Sensi Seeds

      Hi Marco,

      Unfortunately, legal restrictions mean we can’t answer grow-related questions or give grow advice on this blog. However, other readers of this blog will often answer questions like yours. Sorry I can’t be of more help, and I hope you continue to enjoy the blog!

      With best wishes,


  4. That’s a solid article about growing cannabis, it’s important to understand the fundamentals of growing marijuana if you want to grow the super nice flowers, thank you for the hard work you put into gathering all of this great info. Have you heard of the new RSPEC Niemi Deep-Red grow lights are designed to enhance flower while still being a great full cycle grow light from seed to flower?

  5. Hello,

    I have a question, what would be a good fertilizer that I can find in Germany?

    Best wishes


  6. I have dune everything you need to do to my plants , but some of them are leggy with not many leaves, can anyone tell me what I am doing wrong

    1. Scarlet Palmer - Sensi Seeds

      Hi Sue,

      Unfortunately, legal restrictions mean we can’t answer grow related questions or give grow advice on this blog. However, we do have the Sensi Seeds Forum where you can ask questions and share your experiences with a thriving community of cannabis and gardening enthusiasts, so please don’t hesitate to join the community!

      With best wishes,


  7. bonjour,

    est-il possible de lire les articles en français? si oui comment?

    merci de votre réponse, bonne journée,


    is it possible to read in french? if, yes, how can i do it?

    thanks for your answer, have a good day,

  8. Maureen Measure

    If my pendulum moves clockwise the plant is male and anticlockwise the plant is female.

  9. Victoria Moore

    Thanks for this info… very useful..
    Going to your site/menu to order some seeds…

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    The Sensi Seeds Editorial team has been built throughout our more than 30 years of existence. Our writers and editors include botanists, medical and legal experts as well as renown activists the world over including Lester Grinspoon, Micha Knodt, Robert Connell Clarke, Maurice Veldman, Sebastian Maríncolo, James Burton and Seshata.
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