When Does Cannabis Flowering Begin Outdoors?

Learn when cannabis flowering begins outdoors so that you can be prepared to enjoy the fruits of your labor!

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The Basics of Cannabis Flowering

For growers in the northern hemisphere, cannabis flowering begins sometime in late September and continues through October. The amount of daylight each day decreases as the season changes from summer to fall, and this is what triggers the flowering response in cannabis plants. Let’s learn more about the basics of cannabis flowering.

What is cannabis flowering?

Cannabis flowering is the process whereby the plant produces flowers or “buds”. This is opposed to the vegetative stage of growth, where leaves and stems are produced. The flowering stage is induced by a change in the ratio of daylight to darkness that the plant experiences (called the photoperiod). Outdoors, this happens naturally when the days start to get shorter in autumn. Indoors, growers can artificially control the light cycle to force their plants to flower whenever they choose.

Once plants have reached maturity and begin producing flowers, they will do so for a period of around 6-8 weeks before entering the final stage of their lifecycle – harvest. During this time, growers need to provide their plants with the right conditions and nutrients to ensure that they produce high-quality buds.

What triggers cannabis flowering?

In the cannabis world, flowering is what happens when a plant goes from producing leaves to producing buds. Flowering is triggered by a change in the amount of light the plant receives each day, also known as the photoperiod.

In nature, the photoperiod changes with the seasons. For example, cannabis plants grown outdoors in the northern hemisphere will receive more hours of darkness in fall and winter, and fewer hours of darkness in spring and summer. This change in the photoperiod tells the plant when it’s time to flower.

You can mimic this natural process by controlling the amount of light your plants receive each day. If you want your plants to flower faster, you can give them more hours of darkness each day. If you want to prolong flowering, you can give them more hours of light each day.

The average cannabis plant will begin flowering after about 6-8 weeks of vegetative growth. However, there are some fast-flowering strains that can flower as quickly as 4 weeks after germination. There are also slow-flowering strains that can take up to 12 weeks or longer to flower.

The best way to determine when your plants will begin flowering is to consult a reputable source like a seed bank or grow Bible. They will list the approximate flowering time for each strain.

When Does Cannabis Flowering Begin Outdoors?

Cannabis flowering begins when the plant receives less than 12 hours of sunlight per day. This usually happens in late September or early October in the northern hemisphere, and in late March or early April in the southern hemisphere. The days are getting shorter and the nights are getting longer, which signals to the plant that it is time to start flowering.

The role of daylight

The role of daylight in cannabis flowering is crucial. As the days get shorter, cannabis plants detect this change and begin to flower. The amount of daylight exposure cannabis plants need to flower varies by strain, but is typically around 12 hours of sunlight per day.

Indica strains tend to flower sooner than sativa strains, and are often ready to harvest by late September/early October in northern hemisphere climates. Sativa strains usually take a bit longer to flower, and are typically ready to harvest by mid-October to early November in northern hemisphere climates.

If you are growing a hybrid strain, it will usually fall somewhere in between the flowering time of indica and sativa strains.

Once your plants have started flowering, they will need 12 hours of uninterrupted darkness per day in order to produce buds. This means that if you are growing outdoors, you will need to ensure that your plants are not getting any light exposure during the nighttime hours. If they are, this will disrupt their natural flowering cycle and can prevent them from developing properly.

The role of temperature

The role of temperature
Cannabis flowering outdoors is temperature dependent. The average temperature during the day needs to be below 25°C (77°F) for flowering to occur. Night-time temperatures can be higher, but not by much. If the average day and night temperatures are above 30°C (86°F), the cannabis plants will not flower regardless of the number of hours of darkness they receive.

It’s not just the average temperatures that are important. The highs and lows are also crucial. If the temperature swings are too extreme, that can inhibit or prevent flowering as well. For example, if it regularly gets up to 34°C (93°F) during the day but then plummets down to 10°C (50°F) at night, that can prevent flowering from occurring even if the average temperature is below 25°C (77°F).

In general, cannabis plants like stability. They don’t like it when their environment changes too much or too rapidly. So, if you live in an area with large swings in temperature, it’s best to find a place for your plants where they will be protected from those extremes. A garage or shed with good ventilation is often a good option.

Tips for Maximizing Your Cannabis Flowering

If you want to grow your own cannabis, you’ll need to know when flowering begins so you can get the most out of your plant. Flowering begins when the plant starts to produce flowers, which is typically around the end of the vegetative stage. Here are some tips to maximize your cannabis flowering.

Use a light deprivation system

To get your cannabis plants to flower sooner, you can use a light deprivation system. This involves using blacklisting material to block out all light for a period of 12 hours or more every day. Doing this tricks the plant into thinking that winter is coming and it will begin to flower.

You can buy light deprivation systems online or you can make your own using materials like black garbage bags and duct tape. Just make sure that whatever you use is completely light-proof so that your plants get the maximum benefit.

Use supplemental lighting

Supplemental lighting can be a great way to maximize your cannabis flower production. By adding extra light, you can encourage your plants to produce more buds.

Here are a few tips to keep in mind when using supplemental lighting:

– Make sure the light is bright enough. A good rule of thumb is to use a light that is at least twice as bright as the sun.
– Use a timer to control the amount of light your plants receive. 14-16 hours of light per day is ideal.
– Be careful not to overwater your plants. Too much water can lead to mold and mildew problems.

Use organic nutrients

Organic nutrients are not only better for your plants, but they are also better for the environment. Synthetic nutrients can runoff into waterways and cause pollution, whereas organic nutrients are biodegradable and pose no threat to the environment. In addition, organic nutrients provide your plants with a more complete nutrient profile, which results in healthier plants that are more resistant to diseases and pests.


In conclusion, the answer to when does cannabis flowering begin outdoors is that it depends on the cannabis strain and the weather conditions in the location where the plant is grown. For most strains, flowering will begin sometime between late September and early October. However, there are some strains that will flower earlier or later than this depending on the variety. In general, indica strains tend to flower earlier than sativa strains.

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