Cannabis plants go through several stages of growth, from the vegetative stage to the flowering stage. The flowering stage is an important period for cannabis growers as it is when the plants produce buds, which contain the plant’s most potent compounds, such as THC and CBD. In this article, we will take a closer look at the first signs of the cannabis flowering stage, as well as the different stages of flowering week by week.
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Cannabis Flowering Stage
The cannabis flowering stage spans 6-10 weeks and is characterized by the rapid growth of buds. Here, plants need a 12-hour light/dark cycle for optimal results. Key management points include:
- Environmental Control: Keep humidity below 50% to prevent mold, particularly for dense strains.
- Feeding: Boost levels of phosphorus and potassium, as these nutrients support flower size and potency.
- Air Circulation: Increase airflow around plants to keep moisture from building up and to simulate natural outdoor conditions.
For tips on choosing equipment for indoor flowering, check out Best Grow Lights.
Pre Flowering Stage: First Signs of The Cannabis Flowering Stage
The first signs of flowering in cannabis plants begin with the appearance of small, white hairs called pistils that emerge from the nodes where branches meet the main stem. This stage, known as pre-flowering, can vary slightly depending on the growing environment. Indoor plants often enter this stage more quickly due to consistent lighting schedules, while outdoor plants begin flowering as daylight hours naturally decrease.
At this stage, you may notice subtle changes:
- Increased Growth: Plants focus energy on bud formation rather than vertical growth.
- Distinct Sex Characteristics: Female plants reveal white pistils, while males form pollen sacs. Identifying and removing male plants early prevents accidental pollination, which can lower bud quality in females.
- Nutrient Adjustments: Shift nutrients to bloom formulas, reducing nitrogen while increasing phosphorus and potassium to support budding.
- Enhanced Aroma: As buds develop, plants begin emitting stronger scents, signaling early resin production.
Monitoring and adjusting environmental conditions during this period can enhance bud quality and yield. Lower humidity to around 50% to avoid mold, and make sure the pH in soil stays between 6.0 and 6.5 for efficient nutrient uptake.
First Signs of Flowering Outdoors
If you are growing cannabis plants outdoors, the first signs of the flowering stage will usually occur later in the season, around August or September, depending on your location. Outdoor plants will start to show signs of the flowering stage as the days get shorter, and the nights get longer.
The first signs of the cannabis flowering stage outdoors are the same as indoor plants. You will see small white hairs forming at the nodes, and the plants will start to grow buds.
what do buds look like when they start to form?
When buds first start to form, they will be small and round, about the size of a pea. As the plants continue to grow, the buds will start to get bigger and denser. You will also start to see the trichomes forming on the buds, which are the small, hair-like structures that contain the plant’s cannabinoids.
Pre Flowering Stage
In this phase, the plant prepares itself to start full flowering. During pre-flowering, adjusting your plant’s nutrients and environment can help maximize yield potential. This stage typically lasts 1–2 weeks, though it may vary by strain.
Key Pre-Flowering Actions:
- Adjust light exposure gradually to avoid shock.
- Monitor growth for signs of plant stress and adjust care routines as needed.
- Prune lightly if needed, to allow light to reach budding areas.
When to Switch from Vegetative to Flowering Stage
The timing of the switch from the vegetative stage to flowering is crucial for a healthy cannabis crop. Most growers initiate flowering in photoperiod cannabis plants by changing the light cycle to 12 hours of darkness and 12 hours of light, simulating the shorter days of late summer and triggering the plant’s flowering hormones. This shift signals to the plant that it’s time to start focusing energy on bud production rather than leaf and stem growth.
For indoor growers, adjusting the lighting schedule gives more control, allowing you to initiate flowering at the optimal size and structure. Photoperiod plants generally benefit from 4-8 weeks of vegetative growth before switching, though some sativas might need longer to reach their potential, while indicas can flower sooner.
Autoflowering strains, however, are unaffected by light cycles and will naturally enter the flowering stage after a few weeks of growth, regardless of lighting. This trait makes them particularly useful for growers with limited space or time, as autoflowers are ready to harvest in about 8-12 weeks from germination.
Additional signs that photoperiod plants are ready for flowering include:
- Sturdy Stem and Root Development: Strong roots and a thicker stem are essential for supporting large buds.
- Desired Height: Once plants have reached about half of their intended final size, it’s generally a good time to transition, as they will continue to grow during early flowering.
- Sexing and Pruning: Identifying male and female plants is essential before flowering, as female plants produce the buds. This is also an ideal time to conduct last-minute pruning or training to maximize light exposure and airflow.
Transition Tips:
- Gradually introduce the 12-hour cycle to minimize stress.
- Avoid light interruptions during dark periods to prevent reversion to vegetative growth.
- Observe plants closely for nutrient needs and modify accordingly.
Watering During Flowering Stage
Proper watering during the cannabis flowering stage is crucial for bud health. Overwatering can lead to mold, especially with dense buds, while underwatering can stress plants and reduce yields. Generally, flowering plants need watering every 2–3 days, depending on environmental conditions.
Watering Tips:
- Water in the morning to give roots time to absorb moisture throughout the day.
- Consider the size and root structure of your plant to determine water needs.
- Nutrient Watering: Use a nutrient solution every other watering to prevent nutrient burn.
Check out our Guide to Watering Cannabis Plants for more specifics.
Best pH for Flowering Stage in Soil
pH balance is essential during flowering for nutrient absorption. The ideal soil pH range for flowering cannabis is between 6.0 and 6.5. Maintaining this range prevents nutrient lockout and ensures that plants receive critical nutrients like phosphorus and potassium.
Tips for Managing pH:
- Test pH levels regularly using a soil or water pH meter.
- Use pH up or down solutions to adjust levels when necessary.
- Watch for signs of nutrient deficiency, as this can signal pH imbalance.
The Cannabis Flowering Stage Week by Week
Week 1: Early Flowering Stretch and Initial Bud Formation
During the first week of the cannabis flowering stage, the plants will continue to grow, and the buds will start to develop. You may notice that the plants are stretching, with the internodes starting to space out. This is a natural part of the flowering stage, as the plants start to divert energy away from vegetative growth and towards bud production.
At this stage, it is important to maintain the correct levels of humidity and temperature to ensure that the plants are healthy and productive. You should aim for a humidity level of around 40-50%, with temperatures between 68-77°F (20-25°C).
Week 2: Bud Development
By the second week of the flowering stage, the plants will have continued to grow, and the buds will be starting to get bigger. You may also start to notice that the pistils on the buds are starting to change color, from white to a light brown or orange.
This is a good time to start training techniques such as low-stress training (LST), which involves gently bending the branches to encourage lateral growth and improve light penetration. You should also continue to monitor the humidity and temperature levels, as well as nutrient levels. At this stage, the plants will require more phosphorus and potassium, which are essential for bud development.
Week 3: Bud Formation and Plant Height
At this point, the plant is well into the flowering stage, and the buds will be getting bigger and more densely packed. The buds will start to form distinct shapes and begin to fill out, and you should start to see small hairs (pistils) emerging from the buds. The pistils will eventually turn from white to orange or brown, indicating that the buds are nearing maturity. The plant will also continue to grow taller, so you may need to consider staking or tying it down to prevent it from falling over.
Week 4: Resin Production and Aroma
By week four, the buds will be significantly larger, and the plant will continue to grow taller. The pistils on the buds will continue to darken, and the plant will begin to produce more resin. The leaves may start to turn yellow, which is normal as the plant redirects nutrients to the buds. You may also notice a strong aroma coming from the plant at this point.
Week 5: Bud Fattening and Energy Consumption
By week five, the buds will be well-formed and beginning to fatten up, they should be dense and covered in resin, and the pistils should be starting to darken. The size of the buds will depend on the strain and growing conditions, but in general, they should be about the size of a golf ball or slightly larger. Keep in mind that the buds will continue to grow and fatten up in the coming weeks, so don’t worry if they’re not as big as you expected at this point.
The plant will be using a lot of energy at this point, so you may notice that the leaves are starting to yellow and die off. This is completely normal and is a sign that the plant is focusing all of its energy on producing the buds. It’s important to keep the temperature and humidity levels consistent during this stage to ensure that the buds develop properly.
Week 6: Continued Bud Development and Maintenance
As your plants enter week 6 of the flowering stage, they will be in full bloom, and the buds will continue to develop and fill out. This stage is crucial for ensuring optimal growth conditions. Focus on maintaining appropriate nutrient levels, as the plants will require a steady supply of phosphorus and potassium to support bud formation.
This week is also an excellent opportunity for defoliation, which involves removing some of the larger fan leaves. This practice enhances airflow and light penetration to the lower parts of the plant, promoting overall health and potentially leading to bigger, denser buds. Pay close attention to your plants’ health and adjust environmental conditions to keep them thriving.
Week 7: Approaching Harvest and Trichome Monitoring
By week 7 of the cannabis flowering stage, your plants will be approaching the end of the bloom phase. The buds will be larger and more resinous than ever, and the pistils will start to turn brown and curl inwards.
This is also a critical time to monitor the trichomes closely. Trichomes are tiny, hair-like structures that cover the buds and contain the plant’s cannabinoids. By observing the color and clarity of the trichomes, you can determine when to harvest your plants for the best effects.
At this stage, it’s also essential to continue flushing your plants to remove any excess nutrients. Be sure to monitor the pH levels of the water to ensure that it remains within the optimal range.
Week 8 and Beyond: Final Preparations for Harvest
As your plants reach week 8 and beyond, they will be nearing the end of the flowering stage. The buds will have reached their peak size and potency, and the pistils will turn a deep red or brown, signaling that they are ready for harvest.
During this final stage, it’s important to start flushing your plants. Flushing involves watering them with plain, pH-balanced water to remove any residual nutrients from the soil. This process can enhance the flavor and smoothness of your final product by ensuring the buds are clean and free from chemical buildup.
When ready to harvest, cut the entire plant down and hang it upside down to dry in a cool, dark place. After the buds are dry, trim them and cure them in airtight jars for several weeks to improve flavor and potency.
Final thought
The cannabis flowering stage is a critical time in the growth cycle of your plants. By understanding the first signs of the flowering stage and monitoring your plants week by week, you can ensure that they receive the best care and produce the highest quality buds. Remember to monitor humidity and temperature levels
FAQ: Cannabis Flowering Stage
How long does the Cannabis flowering stage last?
The flowering stage can last anywhere from 6 to 10 weeks, depending on the cannabis strain and growing conditions.
What temperature and humidity should be maintained during flowering?
Aim for 18–27°C (65–80°F) and keep humidity under 50% to prevent mold and encourage resin production.
How often should I water my plants during flowering?
Water every 2–3 days, but adjust based on soil dryness, plant size, and environmental conditions.
Can I switch to flowering by just adjusting the light cycle?
Yes, for photoperiod plants, a 12-hour dark cycle typically signals the plant to begin flowering.
