Sales Hotline +1 (855) 904-4090
Great! 4959 Reviews on
  • Secure Payment
  • Discreet Packaging
  • Buy 2+ Products & Get FREE SHIPPING!
  • High Quality Seeds for Sale

The Cannabis Flowering Stage

Apr 20, 2020
The Cannabis Plant

What Happens During the Cannabis Flowering Stage?

The flowering stage is a pivotal time in the life of a cannabis plant. During this phase, plants start to produce flowers (buds), and in the end, growers harvest those buds. While the vegetative phase focuses on outward and upward growth, the flowering stage sees the plants shift their focus toward the production of those sweet, sticky buds we all want. Plants become more sensitive during this time, and a minor mistake can be catastrophic. With the information in this guide, you’ll learn how to handle your flowering cannabis plants properly.

In the Beginning

Somewhat counterintuitively, the flowering phase doesn’t begin when flowers emerge. Rather, it starts when the plants detect slight changes in the level of light they receive. Though many growers assume these changes come when winter approaches, it simply means that plants spend more time in the dark.

When the plants meet their light threshold, they may start to grow tall very quickly. In many cases, cannabis plants can double in size during the initial two weeks of the flowering phase.

Further into the Flowering Stage

Cannabis plants like white widow and ak 47 fem develop leaves and stems during the first one to three weeks of the flowering phase. However, their growth quickly changes to bud formation at the end of the month. All plant components needed for a successful harvest grow within the first several weeks of the flowering stage, and even the slightest problem may affect the overall yield.

When cannabis is planted outdoors, the start of flowering is determined by the season and the location where it’s grown. Strain selection also plays a role. While some plants (such as autoflower marijuana seeds) flower right away, photoperiod strains have a longer darkness threshold that makes them stay in the vegetative stage longer.

Indoor growers face their own challenges because they have greater control over lighting, so it’s possible to force your plants into the flowering phase. As flowering begins, the internodes become narrower and plant growth slows. In the beginning, it may seem as if growth has stopped, but that’s not the case. During the beginning of the flowering phase, growers should pay attention to the quality and quantity of nutrients used.

Initiating Early Flowering in Cannabis Plants

Outdoor-grown cannabis plants start the flowering process on their own, but it’s still possible to jumpstart the process. Why would a grower want to do so? Early flowering leads to an earlier harvest, and it’s easy to do. Cover the grow tent with black sheeting or by turning off your LED grow lights. With changes to the lighting schedule, the plants will know that it’s time to start flowering.


Great care should be exercised during flowering. You’ll need to ensure that no light seeps into the grow room during the 12 hours of darkness, as even the smallest amount of light will delay flowering. Depending on the strain you’ve chosen, the plants may need slightly more or less time in the dark.

Cultivating Auto-Flowering Cannabis Strains

When growing auto-flowering marijuana seeds for growing indoors, it’s not necessary to provide plants with continual darkness. These cannabis plants start to flower on their schedule. Though they’re smaller than other plants and offer decreased yields, the length of the vegetative stage is far easier to predict.

As the flowering phase begins, you’ll notice several changes, with slowed growth being the most notable. The plants will stop producing leaves, and pistil growth will speed up. Additionally, flowers will develop from the plants’ buds. It’s at this time that a plant’s gender is revealed. Females will develop pistils, while males grow pollen sacs. Male plants will grow taller so they can pollinate nearby females.

Identifying Plants by Gender

There are several ways to separate cannabis plants by gender. Though both sexes develop flowers, there are differences to consider. Female plants’ flowers contain white, hairy stigmas, while male plants’ flowers are small and pale green, purple, yellow, or red.

The way plants are treated during this phase will determine the potency and THC content of the final product. To get the most potent buds, it’s important to prevent fertilization by removing male plants from the grow room. Of course it doesn’t hurt to start with high THC seeds like bruce banner feminized seeds or gorilla glue strain seeds aavailable at

Aside from the growth of flowers, the plants’ internodes will extend. Leaves will develop a transparent, sticky coating. As the initial four weeks of the flowering stage draw to a close, female plants’ flowers may develop clusters. These will gradually turn into buds. However, there’s still some work to be done before harvest time comes around.

Plant Upkeep During the Flowering Phase

Before the flowering stage begins, growers should ensure the health of their plants. Leaves should not be discolored, and the plants should not show signs of stress or nutrient deficiency. If any abnormalities are detected, bring the plants back to good health before moving on to the next part of the flowering phase. If the plants have been well fed, consider switching to a flowering formula during the first part of this phase. Don’t make any changes until the plants have developed pistils and stamens.

Proper Nutrient Usage

When the flowering stage begins, the plant’s nutrient requirements will change. Here, cannabis plants may need more potassium and phosphorus. It’s important to give plants enough of these nutrients so they can keep up with the rapid changes they experience during this time.

Before changing fertilizers, though, it’s crucial to make sure that the growing plants are ready to enter the flowering phase. The fertilizers used during vegging typically give plants what they need to start flowering. However, flowering formulas will meet the plant’s needs as they continue through this life stage.

Flowering fertilizers should be used only within the first month of the flowering phase. Growers should note that, during this time, their plants are more vulnerable to environmental factors and nutrient deficiencies. Be sure to give the plants plenty of attention and watch for signs of pest infestation and disease.

Preventing Overfeeding

During the last few weeks of the flowering phase, nutrient use should be avoided. The plants may shed a few leaves in lower and shaded areas. These changes are normal, occurring as the plants shift their focus to bud development. However, your purple kush plant’s leaves start to drop quickly or become discolored, overfeeding is the most likely culprit. Tend to these plants immediately to minimize the risk of bud damage.

Training Plants During the Flowering Phase

When cultivating cannabis indoors, the plants should be trained during the first four weeks of the flowering phase. With training, you’ll maximize the usage of the growing space and increase yields.

Why is it so important to train plants from the beginning? Cannabis plants’ stems are flexible and easily manipulated at this time. However, as the weeks go by, those stems become stiff and woody.

Low-stress training is one of the most effective methods. Here, the stems are trained to grow horizontally, not vertically. LST helps the plant’s canopy develop evenly, and it may increase the area light reaches. With low-stress training, yields may increase by 40% or more.

During the Second Month of the Flowering Phase

From the fifth week of the flowering phase, plants start getting ready for the harvest. They’ll become noticeably thicker and buds will develop. The sticky resin that appeared on the leaves during the first four weeks will darken and acquire a pungent aroma.

If you’re not prepared, these changes may spell trouble. The plants will get heavier and need support from a trellis or another form of bracing. During this time, the plants should get plenty of air. Without good airflow, the plants may develop fungal, mold, and bacterial infections that affect crop yield and quality.

In the second month of the flowering phase, it’s easy to tell if there are male plants in the garden. While most growers have already removed the males by this time, the occasional hermaphrodite may pop up. These plants often contain male reproductive organs that fertilize female plants and diminish their THC potency.

Conditions in the Grow Room

During flowering, indoor growers should ensure favorable conditions in the grow room. Because these plants grow close to one another, it may be necessary to adjust the humidity and temperature to prevent disease and fungal infection. Keep the grow room’s temperature between 68 and 77 degrees at the leaf level and 68 degrees at the roots (when the lights are on). When the lights are turned off, it’s okay to drop the temperature to 68 degrees. When the grow room’s temperature is high, its CO2 level should be high as well.

As the flowering stage starts, the humidity level should be at 40-50%. Once you’ve reached the second month, the level can safely be dropped to 30%. Though the flowering phase comes with a lower recommended humidity level than the vegetative phase does, it’s important to the crop’s success.

Monitoring pH Levels

If the growth medium’s pH level is off, your plants may suffer serious damage. Whether you’re using soil or a hydroponic setup, it’s important to check the pH level continually. Cannabis plants exhibit several signs when the pH is incorrect, with wrinkly, curled leaves being the most visible sign. Soil-based gardens should stay at a pH of 6.0 to 7.0. In hydro gardens, keep the pH between 5.5 and 6.5.

Preparing for Harvest

From beginning to end, the flowering phase takes about two months. With certain strains, though, it may be extended by a couple of weeks. Plants are ready to harvest when the calyces and pistils become red and swollen. The flowers will move closer to one another, eliminating empty spaces. During the final weeks, the bud’s THC levels increase, protecting them from insects.

Two weeks before harvest, be sure to flush the growth medium. Flushing makes the product enjoyable and safe because it rinses away the nutrients and minerals the plants have received. To flush the plants, use pH-balanced water that’s been checked.

The time within which the harvest occurs has a significant effect on the final product. All plants have unique timing, and it depends on the strain selected. Most breeders and seedbanks recommend the appropriate timeline for a successful harvest. If you’re looking for an energetic high, harvest early. However, if you want a more relaxed feeling, wait a bit to harvest the buds. Harvesting at the right time prevents undesirable effects such as a harsh taste.

How to Tell When a Plant is About to Begin Flowering

Only the grower can determine how long their plants will stay in the vegetative stage. However, it’s important to remember that, even when plants reach the flowering phase, they’ll still grow bigger. Therefore, you should consider the size of the grow room when deciding how long to let your plants veg. It’s better to have a growing space that’s a little too large than it is to end up with crowded plants.

The Bottom Line

The flowering phase is one of the most important stages in a cannabis plant’s life. Growers should apply due caution and care during the process as even a minor mistake will adversely affect the crop yield. As the garden moves from the vegetative phase into the flowering stage, pay attention to environmental factors such as growth medium pH, humidity, and room temperature. Be sure to give the plants enough nutrients and flush them two weeks before harvest time.

The most crucial part of cannabis cultivation is paying attention to the crop. While plants can’t speak, they’re good at telling growers what they need and how they’re doing. Before getting started, read some grow literature and learn about the phenotype and genetics you’re dealing with. In doing this, you’ll assure that your cannabis plants are the best they can be, and you’ll be richly rewarded with a plentiful harvest of sweet-smelling buds from your premium weed seeds. The best crops start with great seeds, and you’ll find them at

Popular Posts
Female Marijuana Seed
Cannabis Plant i49 Genetics USA
Check All Popular Posts

Buy Fast Flowering Weed Seeds

Grow Cannabis Flowers From Seed

Related Posts
Vegetative Stage Cannabis

Everything You Need to Know About the Vegetative Stage

Everything you Need to Know About the Vegetative Stage Contents When does the vegetative stage start? What happens in the vegetative stage? ...
Is weed legal in Florida

Is Weed Legal in Florida?

Is Weed Legal in Florida? Contents Florida marijuana laws Is buying cannabis legal in Florida? Can I grow my own cannabis in Florida? Is can...
Is weed legal in California

Is Weed Legal in California?

Is Weed Legal in California? Content California marijuana laws Is buying cannabis legal in California? Can I grow my own cannabis in Califor...