The Complete Guide to the Growth Stages of Cannabis
Anyone who wants to grow cannabis successfully – whether for CBD flowers in Switzerland or as part of legal projects – needs to understand that this plant goes through different life stages. Each stage has its own specific needs for light, water, nutrients and care.
In this article on weedx.ch we take you by the hand and guide you step by step through the four main growth stages of the cannabis plant: from germination of the seed to the decisive moment of harvest.
Stage 1: Germination
Duration: approx. 1 to 7 days
It all starts with the seed. In this very first stage, life awakens inside the seed.
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What happens? Moisture and warmth activate the embryo. A taproot breaks through the shell and grows down into the medium, while the first shoot (the seedling) reaches up towards the light.
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Needs: the most important factors are warmth, moisture and darkness (until the shoot breaks the surface). Many growers use the paper towel method or place seeds directly in special germination cubes (such as rockwool).
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Light cycle: as soon as the seedling appears, it needs light. Weaker light sources are often enough at this stage (such as fluorescent tubes or special seedling LEDs) on an 18/6 or 20/4 (light/dark) cycle.
Stage 2: The seedling stage
Duration: approx. 2 to 3 weeks
Once the first “true” leaves appear (not just the round seed leaves), the plant enters the seedling stage.
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What happens? The plant is extremely sensitive at this stage. It focuses on building a stable root system and forming its first fingered leaves.
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Needs:
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Light: intense light sources can burn seedlings. Keep the lamp far enough away.
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Nutrients: seedlings need very little to no additional nutrients. Overfeeding at this stage is fatal.
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Environment: high humidity (approx. 65–70%) is ideal, as the roots are still weak and the plant absorbs moisture through its leaves.
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Stage 3: The vegetative stage
Duration: approx. 3 to 8+ weeks (adjustable for photoperiod plants)
This is the stage of massive growth. The plant starts to build its structure.
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What happens? The plant produces leaves, stems and branches at a rapid pace. It “vegetates” and becomes tall and bushy. This stage also reveals the plant’s sex (males form pollen sacs, females small white hairs/pistils) – crucial for growers who want to harvest flowers.
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Needs:
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Light cycle: photoperiod plants stay in this stage as long as they receive at least 18 hours of light.
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Nutrients: the plant now has high requirements, especially for nitrogen (N), to build leaves and stems.
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Care: this is the ideal time for training methods (such as LST or topping) to shape the plant’s structure and increase yield.
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Stage 4: The flowering stage
Duration: approx. 6 to 12+ weeks (depending on strain/genetics)
The moment every grower is waiting for: the plant starts to form flowers.
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What happens? With photoperiod strains, flowering is triggered by changing the light cycle to 12 hours of light and 12 hours of total darkness. The plant stops vegetative growth and focuses on producing resin and flowers (buds). Autoflowering strains flower automatically after a certain time, regardless of the light cycle.
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Needs:
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Nutrients: the need for nitrogen drops, while the need for phosphorus (P) and potassium (K) rises sharply to form dense flowers.
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Environment: humidity should be lowered (to approx. 40–50%) to prevent mould in the dense buds.
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Harvest: timing is crucial and is often determined by the colour of the trichomes (resin glands). They should change from clear to milky white and finally to amber.
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Conclusion: patience and understanding
Growing cannabis is a journey. Every stage needs attention and the right care. If you understand your plants’ needs at each stage, you lay the foundation for healthy plants and a rich harvest of aromatic flowers.
Quality starts at the source: at weedx.ch we’re proud to offer only products that have gone through these stages under optimal conditions. Discover our selection of first-class CBD flowers, grown with the utmost care by passionate growers!
Sources & further reading
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Royal Queen Seeds: The cannabis growth cycle: from seed to harvest. (Detailed overview of the stages.)
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Leafly: How to grow marijuana: the ultimate guide.
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Canna: Plant growth and flowering. (Botanical explanations of the stages.)
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Alchimia Grow Shop: Stages of cannabis cultivation: from seed to harvest.
