Fraser Horton
Fraser Horton
Last Updated on May 14, 2021

To get from seed to bud, the cannabis plant needs to go through its specific growth stages. Both photoperiod and autoflowering strains go through the same life cycle, although the stages may take longer for photoperiod strains. To get from seedling to harvest, and ultimately to curing the resinous buds, marijuana plants go through four growth stages:

  • Germination stage;
  • Seedling stage;
  • Vegetative stage;
  • Flowering stage.

Each stage is essential for growing quality cannabis plants, and during each one the plant requires specific conditions to thrive. For the purpose of this article, we’ll go over all the stages of growth in cannabis plants and focus on how long it takes for weed to flower.

Important Factors for Growing Cannabis Plants

For those thinking about starting cannabis cultivation, it’s important to remember that cannabis plants need some essential equipment and growing conditions in order to thrive. 

The Light Cycle

So, when you plan how to set up your grow room, the first thing you need is appropriate lighting. Plants have different light requirements at each stage. The first stages of cannabis growth will require more hours of light, and as the plant reaches the flowering stage, it will need more hours of darkness and less light (about 12h/12h). 

The Amount of Nutrients

The next important factor would be choosing your growing medium and the amount of nutrients your plants will need. When it comes to the growing medium, cannabis plants can be grown in coco, hydroponics, or soil, depending on what the grower chooses. They’ll also need some essential macronutrients like Nitrogen (N), Phosphorus (P), and Potassium (K), and micronutrients like Calcium, Magnesium, Sulphur, Manganese, Boron, Zinc, and Copper. A balanced amount of nutrients will result in a healthy marijuana plant.

Water, Warmth, and Humidity

Growing cannabis plants require adequate hydration, humidity levels, and temperature. These conditions should be at optimum levels to ensure your plant is thriving and to prevent the plants developing mold or bud rot.

Cannabis Plants Growth Stages

It’s crucial for cannabis growers to get acquainted with all the cannabis growth stages so they’re able to create the ideal growing conditions for their plants.

Seed Germination

Germination is the first stage in the cannabis life cycle that begins with a hard and dry cannabis seed and can last between 3-10 days. Once the seed is placed in water, it will start to sprout (for more information look at our sprouting guide). And after it has sprouted, it needs to be transferred into a growing medium. This stage doesn’t require artificial lighting, and germinating seeds should be kept in a cool, dark place.

Seedling Stage

The seedling stage lasts between 2-3 weeks during which the cannabis plant develops fan leaves and small roots. Once the plant gets to this stage, it needs plenty of light, and also a bit of water and nutrients.

Vegetative Stage

The vegetative stage is the period during which the plant grows even more and develops its reproductive organs. At this point, growers are able to tell whether they have a male plant or a female plant on their hands. This stage can last between 3-16 weeks.

Flowering Stage

The flowering stage is the final stage in the life cycle of the marijuana plant, and after it ends, the plant is ready for harvesting. It can last between 8-11 weeks, depending on the strain. Indicas take about 10 weeks, and Sativa strains might take longer.

Cannabis Flowering Stage Timeline

The flowering period is the most crucial one in the life cycle of cannabis plants as it greatly affects the yield and quality of the plant. Different cannabis strains have different flowering times, although there are some general guidelines that are specific to the marijuana plant. The cannabis flowering stage begins at about 3-4 weeks in autoflowers, and at 5-16 weeks in photoperiods

Week 1 

The first few weeks of the flowering phase are transitional, meaning, some plants can even grow double in height to prepare for the oncoming load of the buds. New leaves will grow at the top of the main colas, stems become stronger and sturdier, and the plant will require more nutrients. In order to use the grow lights more efficiently, some growers decide to use low stress training techniques (LST) like SOG, ScrOG, and others.

Week 2

During the second week of flowering, female cannabis plants may develop their white hairs (white pistils) in places where fan leaves connect to the main stem. This is where the buds will develop in the following weeks. During the same period, male plants will grow pollen sacks instead of pistils. It’s important that both male and female plants are separated during this period to prevent the male flowers from pollinating the female ones.

Week 3

During this period, the cannabis plants will have grown twice in size as buds slowly start to develop. Even though there will only be a few resin glands and trichomes on the plant, more will start developing soon. It’s important to check for potential deficiencies, or yellowing leaves so you can calibrate the levels of nutrients you add to your plants. That will prevent both nutrient burns and nutrient deficiencies which can affect photosynthesis and result in smaller buds.

Week 4

During this period, the cannabis plant will likely stop growing and focus on forming bud sites, fattening the budlets, and growing more trichomes that will produce cannabinoids and terpenes. After the plants have stopped growing, growers won’t need to use training techniques, they’ll only need to focus on having structural support for the loaded bud sites.

Week 5

During week 5, the buds will become thicker, and some new buds may grow along the main cola. Trichomes will become milky white, the pistils will turn a darker color, as the plants near the harvesting stage.

Late Flowering Stage (Weeks 6-8)

The general guideline for the length of the flowering stage is about 8 weeks, although not all cannabis strains require the same amount of time to flower. About two weeks before the plant is ready to harvest, you should start flushing the cannabis plant to get better buds that won’t have an unpleasant chemical taste. When the plant nears the end of the flowering stage, you need to check the plants to see if they’re at peak THC levels and ready for harvesting (check our guide to see if your plant is ready to be harvested). 

Final Thoughts on Cannabis Flowering Plants

Growing marijuana plants can be a bit discouraging, especially for inexperienced growers. In order to get your plants from the veg stage, through the flowering stage, to harvest, follow the tips below:

  • Sex your plants out and separate male plants, female plants, and hermaphrodites.
  • Maintain adequate nutrient levels by correcting nutrient deficiencies.
  • Learn about proper humidity levels and temperatures that will enable your plants to thrive during the flowering stage.
  • Make sure you get the appropriate grow lights for the specific strain you’re growing.
  • Don’t transplant your plants if they’re nearing their blooming period.
  • Defoliation could be important for letting the plants focus on growing cannabis buds of higher quality instead of more leaves.
  • Avoid light burn and nutrient burn.
  • Maintain good airflow to prevent bud rot.

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