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Flowering Stage Of Cannabis Plants – Week By Week

Cannabis goes through four stages of development: germination, seedling, growth, and flowering.

You’ve had a hard time taking care of cannabis as a seed. You have also done a series of training techniques to help the cannabis grow as you want.

The flowering stage is the final step. Whether your harvest is worth it, the flowering stage plays an important role.

Don’t make any mistakes. Check out Flowering Stage in Cannabis Plants – Week By Week to see the changes of cannabis. From there, you’ll have a to-do list, so you don’t waste your growing time.

When Does The Flowering Stage Begin?

When does the flowering stage begin
When does the flowering stage begin

Outdoor and indoor cannabis, although of the same breed, will have different stages of growth. Therefore, the time when cannabis enters the flowering stage also changes.

Cannabis grown outdoors usually blooms in the fall. Cannabis grown outdoors is seasonal because the plant is highly dependent on natural conditions such as light, temperature, humidity. 

During autumn, the number of hours of sunshine decreases. Cannabis realizes winter is coming, needs to flower before the weather gets too cold quickly.

With indoor cannabis, normal cannabis strains will begin to flower after a growing period of 6 – 10 weeks.

However, in not every growing period, cannabis can flower. In order for cannabis to enter the flowering stage, you absolutely must re-adjust the light and dark cycles: 12 am and 12 pm.

Some auto-flowering cannabis strains have a shorter growth period. After only about four weeks of going through the vegetative phase, the cannabis will automatically enter the flowering stage.

How Long Is The Flowering Stage Of Weed?

The flowering phase of cannabis lasts an average of 7-9 weeks. Depending on the cannabis strain you choose and environmental conditions, the time may vary.

Sativa cannabis strains have an extended flowering period: 10-12 weeks. Notably, purebred Sativa can take up to 16 weeks to complete its flowering cycle. However, in return, the vegetative phase of Sativa is shorter than that of some other cannabis strains.

Meanwhile, Indica cannabis strains have an average flowering period of 8 weeks. Some Indica and Sativa hybrids will inherit the fast-growing advantage of the Indica strain, which has a flowering period that lasts only 6-10 weeks.

Flowering Stage In Cannabis Plants – Week By Week

7-9 weeks of flowering again divided into three smaller stages. Specifically, the beginning of flowering lasts for the first three weeks, the middle flowering period lasts for 4-5 weeks, and the flowering period lasts from the 6th week onwards.

Every small stage, your cannabis has big changes. Here are the signs of how marijuana changes week by week:


Week 1 cannabis flowering stage
Week 1 cannabis flowering stage

Seasonal variation in the number of hours of sunlight or adjustments in daylight hours is required for cannabis to enter the flowering stage.

During the first week, cannabis will assume that winter is approaching. The tree will have to complete its growth cycle before the climate becomes more extreme. Therefore, cannabis will accelerate the growth rate.

The height and even the size can double as the first sign of the flowering stage. In addition, at the top of the main colas, some new leaves are growing. Cannabis gradually becomes stronger and stronger.

In the first weeks of the flowering period, you need to keep a few points in mind.

First, don’t stop providing nutrients to the plant. Although cannabis has entered its final stage, nutritional requirements have not decreased. You should maintain your normal nutrition for at least the first week of the flowering period.

Second, you can also still train for cannabis during this time. Since cannabis continues to grow in height during the first weeks of flowering, the best training technique is Low Stress Training (LST).

You only need to bend the stem to maintain the flat foliage as you did throughout the growing period. Thanks to a simple technique, cannabis can be exposed to more light during flowering without too much pressure. From there, you can expect a significant increase in cannabis yield.


week 2 cannabis flowering stage
Week 2 cannabis flowering stage

The most important change in the second week of cannabis flowering is the sex of the plant.

On female cannabis plants, you will spot the first white pistils. Pay attention to where the large leaves grow. At that position, you can easily recognize the soft white hairs. Those white hairs, after 2-3 weeks, will develop into young shoots.

On male cannabis plants, instead of the white pistils, you will see small pockets of pollen.

No buds will arise from male cannabis. That is one reason you should get rid of male cannabis plants to focus on caring for female cannabis. Also, a more important reason is that male cannabis will pollinate female flowers, causing even female plants to develop seeds instead of buds.

Therefore, during the early flowering period, especially during the second week, the most important thing is to detect and remove male cannabis plants.

Conventional cannabis seeds are 50% female and 50% male. But why bother taking care of half of the cannabis that won’t bring you a single bud?

From the very beginning, my advice is to look for selective seeds for the highest percentage of female plants. Then, during the first weeks of the flowering period, keep an eye on it to ensure that there isn’t a single male plant mixed into your cannabis garden.

Also, starting from the second week, you need to change the nutritional intake of cannabis. Do not give too much nitrogen during this stage because nitrogen can inhibit growth and give an unpleasant taste to the buds.


week 3 cannabis flowering stage
Week 3 cannabis flowering stage

During the third week of the flowering period, the cannabis slows down and tends to stop altogether. However, at this time, cannabis also has a much larger height and size when compared to the plant in the growth stage.

In addition to taking growth, the biggest change in the third week that you may notice is the first sign of buds. In the places where you found the soft hairs in week 2, your first shoots are growing.

Buds during this time are not large in size, and the smell is too impressive. Because during the third week of the flowering period, the sap glands and trichomes on the plant are not yet fully developed. 

By the end of the third week, you will be able to clearly notice the location of the buds at the tips of the plants. Because of the appearance of the buds, you have more to pay attention to.

Most importantly, you should not defoliate during this time. Buds will appear in all locations with white stigmas. That means cutting off the fan blades will stop the buds from growing.

Minimize touching the area where the buds are forming. Additionally, do not conduct any High-Stress Training techniques during this critical period.

Cannabis will consume more and more energy for the flowering stage. Therefore, you need to add nutrients to the plant constantly. But first, you need to know what kind of nutrition cannabis requires.

The best way is to observe the color of the leaves. A well-developed cannabis plant will have bright green leaves. Meanwhile, dark leaves are indicative of an excess of nutrients. Similarly, yellowing leaves are a sign of nutrient deficiencies.

In addition to checking the nutrition of cannabis, you need to be concerned about problems related to pests, molds.

The first three weeks of the flowering period are the easiest to eliminate these hazards. Otherwise, when the cannabis has actually bloomed, you will regret not having removed the mold and pests before that.


Week 4 cannabis flowering stage
Week 4 cannabis flowering stage

During the fourth week of the flowering period, the cannabis stops growing in height completely. Instead, the plant’s buds are constantly getting bigger. 

You can still see the white hairs sticking out. In addition, marijuana will create more Trichomes, resulting in a more noticeable scent.

You may also see some changes in the cannabis leaves. Some older leaves will turn brown and fall off.

If the number of fallen leaves is not large, do not worry too much. This is a completely normal phenomenon. What you need to pay attention to is to adjust the temperature and humidity accordingly.

Your cannabis will not grow any more leaves from this point on. If there are not enough leaves, it will be difficult for cannabis to absorb enough light to convert into energy, resulting in high yields.

Therefore, you should protect your existing leaves well by stopping training techniques like topping or defoliation. In addition, as cannabis does not continue to grow, some training techniques are no longer necessary.


Week 5 cannabis flowering stage
Week 5 cannabis flowering stage

At week 5, the number of shoots is significantly more. The old shoots continue to grow to a larger size. Meanwhile, new shoots grow along with the main cola. Buds appear all over your cannabis, which is a sign of a good crop.

The dense number of buds also makes the scent of cannabis more intense. You should check your ventilation system if growing cannabis indoors.

Besides the change in the buds number, week 5 also witnessed a change in the color of some hairs on the pistil. Instead of being white, the fur turns darker. When the hairs turn brown or amber, your cannabis is nearing its final harvest.


Week 6 cannabis flowering stage
Week 6 cannabis flowering stage

Week 6 is one of the last weeks of the flowering period. Not much has changed during this period. The shoot is the fastest-growing part. You can feel the stickiness to the touch, and the scent is quite heavy when you smell it.

Weeks 7, 8

Week 7, 8 cannabis flowering stage

Not every cannabis strain can be harvested after 8 weeks of flowering. However, from week 7 onwards, you are very close to the results.

There won’t be too much of a difference in the final 3 week period. Therefore, whether your cannabis is harvested at the 10th or 7th week, you can refer to the directions for the right time.

You can only harvest cannabis when the THC content of the plant is at its highest. To recognize the THC content in a plant, you need to observe Trichomes. Using a small microscope to look at the triple leaf of cannabis is the simplest way to test for Trichomes.

If Trichomes are transparent, do not rush to harvest. Conversely, if the Trichomes turn amber, the flowering stage of the cannabis can stop here.

What Is Attention In Cannabis Flowering Stage?

The Size Of The Plant

The size of the plant is proportional to the size of the pot. Especially during the flowering stage, cannabis can grow rapidly; too small a pot size can affect the height of the plant.

Repotting is probably the first solution that comes to mind. However, you should remember, any stress during the flowering period can affect shoot yield.

Therefore, it is better to choose a large enough pot in the first place. Or, if you want to transplant before the flowering period is the best time.


Nitrogen (N), Phosphorus (P), and Potassium (K) are three essential nutrients for any stage of cannabis growth. However, during the flowering period, the importance of these three nutrients changes.

The Role Of Nutrients

Cannabis in the flowering stage does not need too much nitrogen. Because nitrogen can affect the taste and size of the buds. Meanwhile, cannabis in the final stage requires a large amount of Phosphorus and Potassium.

During the first three weeks of the flowering period, cannabis requires a large number of nutrients to both grow plant height and develop bud size. The recommended amount of N P K in this stage is 1:3:2.

From week 4 on, your cannabis focuses entirely on developing bud size. The formula NPK 6:15:10 will help the buds grow larger, the fragrance more intense.

In the final weeks, make sure your cannabis doesn’t have a problem with nutrient deficiencies or excesses. 

In the last few days, stop providing Nitrogen for cannabis. The NPK ratio should be 0-3-3. Instead, you should give more calcium to the plant.

PPM Index

To control the number of nutrients in the soil, you cannot ignore the PPM.

PPM is a unit of measurement for nutrients in growing media, whether soil or hydroponic. Devices that help measure PPM will help you assess the nutrient level of the soil or growing medium.

In the early flowering stages, cannabis will grow best if the soil or growing medium reaches 950 – 1000 PPM. When the plant begins to flower, the nutrient level should reach 1000 – 1100 PPM.

Through the measurement, you find that the amount of nutrients in the soil is too much. The next time you fertilize, you should take the suggested PPM to subtract the PPM of the environment. Thus, cannabis will avoid the danger of excess nutrients leading to leaf burn.


Lighting for cannabis flowering stage

Lighting for cannabis during the flowering period should be adjusted as a general rule: 12 hours of light and 12 hours of darkness continuously.

With indoor cannabis, it’s very easy to adjust your light-dark cycle.

You just need to change the lighting schedule and make sure there are no interruptions. Be prepared for a power outage that renders the lighting system inoperable. 

At the same time, you also need to check that your growing room is closed enough so that no light can get in when the cannabis enters the midnight darkness.

You need to wait until the day starts to shorten with outdoor plants, usually in the fall. Your cannabis will flower naturally when the hours of sunshine are shorter than 12 hours per day.

All you need to do is prevent the plant from being exposed to light for the remaining 12 hours. Street lights, even headlights, shouldn’t be on when marijuana is in the midnight period.

What happens to cannabis if you don’t guarantee 12am/night during the flowering period?

Short 12 hours of darkness per day can cause cannabis grown outdoors to remain in its vegetative stage. That is, the plant cannot enter the flowering and budding phase.

In addition, it is also difficult for cannabis to flower properly if you mess up the plant’s light and dark cycles. In the worst case, most cannabis will have hermaphroditic flowers. And of course, you won’t have the desired crop.


Temperature for cannabis flowering stage

The temperature is too high or too low. In every stage, cannabis is inevitable, especially during this critical period. You won’t want to run into heat-related troubles in this final stage.

General principles of temperature for cannabis in the flowering stage

A little lower temperature would be better. Because the buds of cannabis will grow quickly with higher Trichome content if the environment is temperate, the temperature is not too high.

If the temperature during the flowering period is too high, the growth of buds will slow down. In addition, the smell and potency of the buds will also be greatly reduced.

Plus, the high temperature also makes the photosynthesis process abnormal. The enzymes in cannabis will decrease potency, resulting in poor protein levels or even disappearance. Your cannabis will probably die if grown in high temperatures for a long time.

During the first three weeks of the flowering period, daytime temperatures should be 26C, and nighttime temperatures should be between 16–18°C.

Over the next 4-6 weeks, you should adjust the temperature a little lower. During the day, the temperature should not exceed 25°C. Meanwhile, the room temperature for growing cannabis at night should be between 16–17°C.

How to help you lower the room temperature

Firstly, you can adjust the amount of air in the room. If you have a ventilation system that removes warm air, drawing in cool air, not only temperature, you can also control humidity.

Secondly, always maintain a schedule to turn off the lights at 12 hours during the day and turn on the lights for 12 hours at night. Maintaining this light-dark cycle not only helps the cannabis flower properly but also warms and cools the air at the right time.

Equipping a timer to turn on/off the lights will make your job easier. Also, if you light up your grow room with HPS lights, don’t skip the cooling tube because the heat emitted by the HPS lamp is much higher than the LED with the same capacity.

And finally, the simplest way: install the air conditioner. Investing in an air conditioner will help you quickly adjust the temperature and control the humidity in the room.


The presence of mold and pests can completely ruin your crop. And did you know inappropriate humidity is the main cause of mold growth and development?

Therefore you should reduce the environmental humidity in the final stage instead of keeping it too high like in the first stage.

The most suitable humidity for the first 3 weeks of the flowering stage of cannabis is 40-50%. Gradually reduce the amount of moisture. When entering the final weeks, make sure that the humidity level does not exceed 40%.

With cannabis grown outdoors, it is difficult to adjust the humidity to exactly 40 – 50%. Because when cannabis enters the flowering stage in the wild, the weather becomes cooler, and the humidity is also higher. The autumn sun is not enough to clear the early dew, which also causes an increase in moisture.

But you can completely reduce the ill effects of humidity on cannabis.

Shielding cannabis from the morning mist is a simple but effective way to do it. In addition, you should move your cannabis pots to dry places, away from wet rain.

With indoor cannabis, you can easily control the humidity.

The first piece of equipment you will need is a hygrometer. For a very small cost, you can check the humidity in the room. From there, you will have measures to use appropriate humidity increase or decrease devices.

A dehumidifier will help remove moisture from the air. An extractor fan can also effectively reduce humidity. And as mentioned above, air conditioning will also help you control humidity.


You have to water the cannabis. During the early flowering stages, you should maintain the same watering schedule as with the growing phase. From week 4 onwards, as the cannabis buds grow, the roots need a larger amount of water.

But how to water so as not to increase the humidity in the air? The advice is that you should water when the cannabis is in the light cycle. The electric light system brings light to the plants for photosynthesis and helps to evaporate a large amount of excess water.

However, you should not expect too much of the water’s self-evaporation. Better yet, you should have an efficient escape system.

Water when your cannabis needs it. The most common watering frequency is every 2-3 days.

You should use your finger to check the moisture content of the water before watering directly. Besides, remember not to spray water on the tips of the buds.

The place that needs water the most is the roots of the plant. And it makes no sense if you try to moisten the tips of the shoots, causing a mold condition.

When there is a lack of water or an excess of water, the signs of cannabis are quite easy to detect. Cannabis leaves that are drooping, curled, and yellow are signs of overhydration. 

Meanwhile, withered leaves are a warning that you need to add water to the cannabis immediately.


Ventilation is key for proper humidity and clean air flow. A well-ventilated environment will help reduce the risk of mold and pests. From there, cannabis will also grow better.

In addition, ventilation also helps dispel the hot air by the electric light system. Cannabis in the flowering stage always requires a low temperature. And the ventilation system will be an indispensable element to reduce the temperature of the growing room.

Besides, the wind moving between the branches also contributes to making the plant more sturdy. When it comes to flowers, being strong is the key to keeping the plant from falling.

Therefore, investment in the ventilation system is never redundant. And fortunately, you also don’t need to invest too much equipment for ventilation.

The ventilation system consists of two main devices: the exhaust fan and the oscillating fan.

The oscillating fan, as the name suggests, will help circulate the air in the room. The oscillating fan can be installed anywhere in the room. However, you should avoid letting the fan point directly at the cannabis, causing unnecessary pressure.

The exhaust fan system has two main tasks: removing stale air and drawing in the fresh air. Along with the exhaust fan system, you should be equipped with a dehumidifier.

With the above combination, you will completely get rid of the old damp air in your grow room.

To deal with unpleasant odors in the cannabis grow room, a carbon filter will be very helpful. By simply attaching the filter to the exhaust system, the terpenes released by the cannabis should no longer be a concern.

pH Levels

pH is a scale that determines the level of acidity or alkalinity. With cannabis, a change in pH can increase or decrease the plant’s ability to absorb nutrients.

A soil pH of 6.0 to 7.0 will prevent the cannabis from being “nutritionally locked” – the roots do not have access to nutrients even when the soil is full of nutrients.

If you grow cannabis hydroponically, the pH is even more important. Because the pH of the water will directly affect the roots, the optimal pH should be between 5.5 and 6.5.

During the flowering stage, the right pH for cannabis to absorb nutrients is 6 – 6.2. In the last three weeks, the most suitable pH is 6.3 – 6.4.

To adjust the pH, you need the support of pH measuring devices and specialized solutions. For example, to lower the pH, you should use solutions such as citric acid. Or, to increase the pH, you can use silicon-based keys.

In addition, natural fertilizers such as compost create an environment for beneficial bacteria and fungi. These organisms will keep the soil condition in general and the pH always at an optimal level.

Flushing Your Cannabis Plants

Flushing cannabis plants

Discharge of cannabis is a step that should be taken before harvesting. Cannabis discharge will help remove excess salts and minerals, including fertilizers in the plant. It will keep the buds purer. If you hate the unpleasant chemical taste, this last step cannot be skipped.

Just as it’s impossible to pinpoint the exact harvest time for each type of cannabis, there’s no one at the same time for you to release it. Generally, you should discharge cannabis two weeks before harvest.

When it comes to cannabis discharge, you will stop fertilizing the plant, whether chemical or organic. All you need is water with a balanced pH.

You should drain the pot with water three times the volume of the pot. Be sure to leave a drainage hole to prevent the plant from waterlogging.

When you stop providing nutrients, cannabis will have to use up all the nutrients stored in the plant. As a result, there is not a single bit of excess fertilizer that can affect the taste of your cannabis.

Step By Step Harvesting Guide

When And How to Harvest Cannabis Plants?


“Flowering Stage in Cannabis Plants – Week By Week” can make you nervous. Because seemingly every mistake in the flowering weeks can affect your harvest.

However, instead of harvesting cannabis too soon, calmly monitor and care for cannabis according to the instructions above. More than 6 weeks can be a long time, but if you know how to take care of it, you will have the best time of the season watching the fruits grow day by day.

Hopefully, the above article will help more than 6 weeks in your flowering period, not too difficult. May your harvest be filled with cannabis buds of excellent size and quality.

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