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How a Cannabis Plant Grows

How a Cannabis Plant Grows

We might know how to smoke it, but how many of us actually know how to grow a cannabis plant successfully from seed to harvest?

Cannabis has been cultivated for centuries and has gained increasing popularity as its legalization has changed across the world. Understanding the growth stages of a cannabis plant is essential for any grower, whether you're just starting to baby your first seedling, or you're already tending to your lush cannabis garden!

In this blog post, we will discuss the different stages of growth in a cannabis plant, so if you are ever curious about these precious plants and their lifecycle, read on! 


The Stages Of A Cannabis Plant 

The phases of a cannabis plant’s life cycle include:

  1. Germination (3 to 10 days)
  2. Seedling (2 to 3 weeks)
  3. Vegetative (3 to 16 weeks)
  4. Pre-Flowering (1 to 2 weeks)
  5. Flowering (8 to 11 weeks)
  6. Harvest!


Germination is a crucial stage in the growth of cannabis plants, and it requires careful attention to detail. If you’d like to grow your own weed, understanding the germination stage is necessary for a successful harvest. 

Germination involves the sprouting of a seedling into a small plant. Germination can take up to 10 days, requiring certain conditions to be met. The seeds must be planted in rich, moist soil and kept warm and humid. The seeds will then grow roots and stems, eventually turning into a small plant.

The germination stage sets the foundation for the plant's development and overall growth. The plant may only grow to its full potential if germination is done correctly.

  • To germinate a cannabis seed, you will need moist soil, water, and light. Cannabis seeds need to be planted in a seedling tray, where they can sprout and develop roots. 
  • Once sprouted, they are now ready to go into the soil. The seeds should be planted at a depth of about 1/4 inch, then covered with a layer of soil. 
  • After planting the seeds, water the soil until it becomes moist but don’t overwater. Overwatering can cause the soil to become too wet, leading to root rot or the seeds rotting before they even germinate. 

There are many common mistakes that cannabis plant growers make during the germination stage. The most common mistake is planting seeds too deeply or too shallowly!


The seedling stage begins when the cannabis seed germinates and sprouts from the soil. As your plant grows, it turns from a sprout to a seedling and develops more leaves with blades or “fingers.” 

At this stage, the plant is very fragile and requires a lot of care and attention. It is also when the plant is the most vulnerable to disease and mold. 

The first few days of growth are crucial, and the plant needs to be kept warm, moist, and in a nutrient-rich environment. It is also essential to ensure the plant gets enough light, as this will help it grow strong and healthy.

In the early days of the seedling stage, the plant will focus most of its energy on developing its root system. It is important to remember that the plant only absorbs water and nutrients through its roots at this stage. 

As a result, it is crucial to keep the soil moist and well-drained to encourage root growth. The best way to achieve this is by watering the plant gently and frequently, ensuring that the soil never dries out completely.

As the plant grows and develops its first true leaves, it will require more light to continue its early growth. It's important to note that the plant should be exposed to only a few nutrients during the seedling stage. 

This is because the plant is still developing its root system and cannot yet absorb many nutrients. Instead, it's recommended to use a mild nutrient solution and gradually increase the concentration as the plant develops.



Now your plant should be REALLY growing! Once you’ve repotted your seedling into a bigger pot, the roots and leaves have room to grow rapidly. 

The vegetative stage is the second stage in the lifecycle of a marijuana plant. It starts after the seedling stage and lasts 3 to 16 weeks, depending on the strain, growing method, and environmental conditions. 

One of the ways to identify the vegetative stage is through the number of leaves on the plant. At the beginning of the vegetative stage, the plant will have two to three leaves. These leaves will grow to seven or more leaves by the end of the stage. Another way to know if your plant is vegetative is by height. The plant will typically double in size by the end of this stage.

The vegetative stage is the best time to train your marijuana plant. Plant training is used to manipulate the plant's growth and productivity. Some popular training methods include topping, pruning, and LST (low-stress training). These techniques help to increase the yield and quality of marijuana buds.

The vegetative stage requires specific light conditions. Cannabis plants are known to be happy with 10 to 12 hours of sunlight a day, but some plants can do with as little as six hours. 

The environment, including temperature and humidity, is crucial in vegetative. The ideal temperature range is between 20-30°C (68-86°F), and the humidity should be between 40% to 70%. A lack of nutrients, overwatering, or underwatering can stunt the plant's growth during this stage.


The pre-flowering stage of the cannabis plant occurs after the vegetative stage and before the flowering stage, typically a month or two after the seedling sprouts. For some plants it can happen up to four months after. 

During this time, the plant is still growing and developing, but it has not yet started to produce flowers. Instead, it is focused on building a strong root system, developing sturdy stems and leaves, and preparing itself for the upcoming flowering phase.

This time is crucial, especially if there’s a chance you have males in your crop. As your plants reach sexual maturity, they also develop reproductive organs. A male cannabis plant will have small balls that will grow into pollen sacs, while the female plant will have pistils. 

It is important to get rid of a male plant as soon as you notice it, as it can fertilize your female plants, negatively affecting the quality of your cannabis output. 

To ensure you always get female plants, the easiest and most effective way to ensure you have female cannabis plants is to start with feminized seeds. These seeds have been bred so that they will almost always produce female plants. 

You can determine the sex of your plants once they begin to grow. Use a magnifying glass if the organs are still too small. Female plants will form small white hairs called pistils at the nodes where leaves and branches join the main stem. 


That’s the moment we’ve all been waiting for! Your plants are now starting to sprout flowers from the pistils. You should watch out for pest populations and lower humidity to reduce the risk of fungal diseases and rot. 

The first sign of flowering is when the cannabis plant shows the preflowers or pistils at the joints where the leaves and branches connect to the primary stem. The plant's growth slows down, and the focus is now on producing flowers, also known as the buds we all know and love. 

The flowering stage can last 8 to 11 weeks, depending on the strain, growing condition, and environment. The plants require more light to ensure the buds develop correctly during this period. Most growers use a 12/12 light cycle where the plant receives 12 hours of light and 12 hours of darkness.

As the flowering stage progresses, the buds develop a sticky resin containing cannabinoids, terpenes, and other essential oils. The trichomes are tiny, hair-like structures that cover the buds and are visible to the naked eye. 

The trichomes' color can provide growers with an idea of when to harvest their plants. Clear trichomes indicate that the plant needs more time to mature, while cloudy or amber-colored trichomes suggest the plant is ready for harvesting.

Maintaining the ideal temperature and humidity levels is crucial for the plant's health and growth during the flowering stage. The recommended temperature range is 20 to 28 degrees Celsius, and the humidity should be 40 to 50%. High humidity levels can lead to mold growth, while low humidity levels can cause the plant to dry out.


You've finally reached the end of your marijuana plant's growth cycle! And now it's time to harvest and reap the fruits of your labor. Harvesting your cannabis plant is a vital step that can significantly affect the potency and quality of your buds, so it’s important to do it correctly.

Knowing when to harvest your marijuana plant is crucial to ensure the best results. There are a few ways to tell if your plant is ready for harvesting. First, check the pistils, the tiny hairs on the buds. When they’ve turned from white to a darker color, that’s the first sign that it’s time to harvest. 

Another way to check is to examine the trichomes, the resin-filled glands on the buds. When the trichomes have turned milky white, that’s a good indicator that it’s time to harvest. Be careful not to wait too long to harvest, as this can result in a loss of potency and a harsher taste.

Before cutting your plant, stop watering it a few days before the harvest to allow the soil to dry up. Get a pair of sharp pruning shears and cut the plant at the stem about two to three inches above the soil. 

Remove the large fan leaves on the plant and then trim the remaining leaves around the buds. Make sure to keep the buds intact and avoid damaging them, as this can affect the quality.

Once the plant has been harvested, the buds need to be dried. This process can take anywhere from five to ten days or even longer. Cannabis is best dried very slowly and under low temperatures. Start by hanging the buds upside down on a string or wire in a cool, dark, and airy space. 

Check the room's humidity and ensure it is around 50%. This helps to prevent mold and mildew from forming on the buds. After a few days, the buds should start to feel dry to the touch but not brittle. 

After they dry, the buds are ready for consumption! Store them in an airtight container in a cool, dark place to preserve their freshness. 


What Time of Year Should You Grow Cannabis Plants?

If you are growing cannabis outdoors, you’ll be at the mercy of the weather and have to watch the changing seasons carefully.

Cannabis is a plant that may grow all year round in some regions. However, the most recommended time to grow cannabis outdoors is early spring. By then, you should have some germinated seeds you’ve started in a secure, ideal environment. You might even have seedlings to plant if you have started growing them indoors in a controlled environment. 

Depending on where you live and the environmental conditions, you should stick the seedlings in the ground by mid-May or early June. As the weather heats, the plants will enter their vegetative stage and require regular training and topping. 

Once fall comes along in September to November, it would be time to harvest your plants. Not every year is the same, and while some years you could harvest in September, some years might be October. 


Final Thoughts 

Now that you know all the stages of the cannabis plant, you can think about growing some of your own! Remember to thoroughly check out Health Canada's regulations to growing cannabis at home, and remember to always source your seeds from a licensed retailer.