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Flowering/Bloom Stage

Growing cannabis in the flowering stage is an exciting phase as it is when the plants begin to produce buds. Here's a breakdown of key aspects and considerations when growing cannabis in the flowering stage:

A circle representing day and night

Light Cycle

During the flowering stage, cannabis plants require a specific light cycle to initiate bud development. Most
commonly, a 12/12 light cycle is used, which means providing 12 hours of uninterrupted darkness followed by 12 hours of light each day. This simulates the natural light cycle that occurs during the late summer and early fall, triggering the plants to transition into the flowering phase.

A cartoon flask filled with a blue liquid


Adjust the nutrient regimen to meet the changing needs of the plant during the flowering stage. Reduce the amount of nitrogen and increase phosphorus and potassium. This shift towards bloom-specific nutrients supports bud development and enhances resin production. Many nutrient manufacturers offer specific "bloom" or "flowering" nutrient formulas that are suitable for this stage.

Three small LED lights


Use high-quality grow lights that emit the appropriate
spectrum for flowering, such as high-pressure sodium (HPS) or
LED lights designed for bloom. It's crucial to maintain
consistent lighting conditions throughout the flowering stage,
avoiding any interruptions during the dark period.

A cartoon watering can


Be mindful of the watering needs of your cannabis plants in the flowering stage. As the plants transition to flower, they may require slightly less water than during the vegetative stage. Monitor the soil moisture levels and water only when the top inch of the growing medium feels dry. Avoid overwatering, as it can lead to root issues or nutrient imbalances.

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Temperature and Humidity

During the flowering stage,
maintain a slightly lower temperature range of 20-26°C (68-79°F) to help prevent heat stress and excessive stretching. Humidity levels should be lowered gradually from the range of
60-70% in the vegetative stage to 40-50% during the flowering
stage. Good airflow and ventilation are essential for temperature and humidity control as well as to minimize the
risk of mold and mildew formation.

A graphic of a plant with long stems


As the buds develop and gain weight, they can put significant stress on the plant's stems. Provide adequate support, such as using plant trellises, stakes, or bamboo rods, to prevent branches from breaking and to maintain an even canopy. This support also promotes better light penetration and airflow, reducing the risk of bud rot and improving overall bud quality.

A picture of a beetle

Pest and Disease Management

Continue to monitor for pests
and diseases during the flowering stage, as they can still affect
your plants. Regular inspections and preventive measures,
such as maintaining a clean growing environment, proper air
circulation, and organic or safe pest control methods, are
important to protect your crop.

A magnifying glass


The flowering stage lasts for several weeks, typically 8-12 weeks depending on the strain and desired maturity. Pay attention to the trichomes (the resin glands) on the buds, using a magnifying glass or a microscope to observe their color and clarity. Harvest at the desired level of trichome maturity, which can range from clear (less potent) to milky/cloudy (peak potency) to amber (more sedative effects).

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It's essential to research and understand the specific requirements of the cannabis strain you're growing, as flowering stages can vary. Adhering to local laws and regulations regarding cannabis cultivation is crucial at all stages of the process.

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