5.1 The flowering phase

The flowering period of cannabis is a crucial phase in the plant's life cycle, during which it develops its flowers (also called buds). This phase begins when the light cycle changes to 12 hours of light and 12 hours of darkness, prompting the plants to begin flower production. Here are some important information and tips regarding the flowering period of cannabis:

Duration of flowering period

The duration of the flowering period varies depending on the variety:

  • Indica strains: These strains typically have a shorter flowering time of about 7-9 weeks.
  • Sativa strains: Sativas often take longer, typically between 10-14 weeks.
  • Hybrids: The flowering time of hybrids can vary depending on the genetic composition and is usually somewhere between the times for Indicas and Sativas.

Phases of flowering

  1. Pre-flowering (weeks 1-2):
    • In the first one to two weeks after the light cycle changes, the plants begin to show sexual characteristics. Female plants develop small white hairs (pistils), while male plants form pollen sacs.
    • It is important to remove male plants to prevent pollination and seed formation in the female plants.
  2. Early flowering (week 3-4):
    • The plants are visibly beginning to bloom, and bud formation is becoming more noticeable.
    • The plants may continue to grow tall (stretch), especially in sativa-dominant varieties.
  3. Medium flowering (weeks 5-7):
    • The buds become larger and denser.
    • Trichomes (resin-producing glands) begin to develop, giving the buds a frosty appearance.
    • The smell becomes more intense.
  4. Late flowering (week 8+):
    • The buds reach their maximum size and density.
    • The trichomes change color from clear to milky and finally to amber, which is a sign that harvest time is approaching.

Care during flowering

  1. Light:
    • Maintain a strict light cycle of 12 hours light/12 hours dark.
    • Avoid any light leakage during the dark period, as this can disrupt the flowering process.
  2. Nutrients:
    • Use a special fertilizer for the flowering phase with higher phosphorus and potassium content and reduced nitrogen content.
    • Be careful not to over-fertilize; this can lead to nutrient burn.
  3. Irrigation:
    • Water regularly, but avoid waterlogging.
    • Reduce watering slightly towards the end of the flowering phase to minimize the risk of mold growth.
  4. Environmental conditions:
    • Maintain a constant temperature between 22°C and 26°C during the light period and between 15°C and 20°C during the dark period.
    • Reduce the relative humidity to about 40%-50% to prevent mold growth on the buds.
  5. Support:
    • If necessary, support heavy branches with stakes or netting to prevent them from breaking.

Determine harvest time

The right time to harvest depends on the trichomes:

  • Clearly, the plant is not yet ripe.
  • Milky: Highest THC content; energetic effect.
  • Amber: THC begins to break down; calming effect.

Use a microscope or magnifying glass to closely observe the color of the trichomes.

Conclusion

Flowering is a critical phase in cannabis cultivation that requires careful monitoring and care. By paying attention to your plants' needs and following the tips above, you can ensure your plants produce healthy and potent buds.