Cannabis Growing & Flowering Stages Guide

A man holding a cannabis leaf up to the sunlight

The cannabis plant goes through four stages as it grows and matures. Those growth stages need varying amounts of water, nutrients, and light to grow well.

For anyone who’s thinking about growing cannabis, it’s crucial to know about these stages, how long they last, and what your plant will need when.

Knowing where your plants are in their life cycle will help you determine when to prune, train, and eventually harvest them.

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From Seed to Weed: How Long it Takes to Grow Cannabis

Growing a cannabis plant can typically take anywhere from 3-8 months. Starting with an auto-flower or clone can speed up the process, though.

If you grow indoors, you can force your plants to flower by changing the light cycle and have a crop in 3-4 months. But if you grow outdoors, you’ll be at the mercy of the seasons.

When’s the Best Time to Grow?

If you’re growing indoors—good news! You can grow cannabis whenever you like.

However, if you’re growing outdoors, the best time to start germinating your seeds is by the end of April. This way, you’ll be ready to harvest between September and November before hard freezes start.

Starting your seeds indoors is a good idea—they are extremely delicate in the early stages. Ideally, your plants will be in the ground, outside, and ready to go by the end of June.

Cannabis Growth: The Four Stages

Let’s break down the cannabis plants’ growth stages into four sectors. From seed to harvest, they are:

The Germination Stage (3-10 Days)

The seed germination stage lasts from three to ten days, and the plant needs 16 hours of light every day.

The first stage starts with the cannabis seed. Your seeds should feel hard, dry, and be a medium brown color. Undeveloped seeds will feel squishy and be green or white in color—these likely won’t germinate.

Once it has germinated, you’ll want to place it in your grow medium (like soil). Then, the taproot will drive down, and the stem will begin to grow upwards.

Next, you’ll notice two rounded leaves growing from the stem—these are called cotyledon leaves. They are responsible for taking in the right amount of sunlight so that your plant can grow stable and healthy.

As roots continue to develop, you’ll notice the stalk rising, and the iconic marijuana leaves begin to sprout. Now, the next stage begins.

The Seedling Stage (2-3 Weeks)

The seedling stage lasts from two to three weeks, and the plant will continue to need 16 hours of light each day.

Once your plant goes from germination to seedling, you’ll see it start to develop more and more of those traditional cannabis fan leaves. Initially, it will produce leaves with a single blade, but as new growth develops, so will additional blades. Mature plants will typically have 5-7 blades on each leaf.

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Your cannabis plant will stay in the seedling stage until the leaves are a vibrant green and the number of blades on each leaf reaches its maximum.

During this stage, the roots are small, and your plant won’t need much water—overwatering is a big concern during these two to three weeks.

It’s also vulnerable to mold and disease during this time. You’ll want to keep away excess moisture and ensure it gets plenty of light.

Even when growing outdoors, many growers start their seeds inside to help them succeed through the delicate seedling stage.


The Vegetative Stage (3-16 Weeks)

The vegetative stage lasts from three all the way to sixteen weeks, and outdoor plants will need a minimum of six hours spent in direct sunlight—and a few more in indirect light. Indoor plants should stay on the same 16-hour light cycle.

Now, your plant will truly start taking off—it’s time to move your cannabis plant to a larger pot as the roots and foliage rapidly start to grow. In the early stages, you’ll want to water near the stalk, but as the roots grow, you’ll want to water further away in the soil so that the plant’s roots can stretch and efficiently absorb more water.

Plants in this stage need healthy soil with plenty of nutrients. You’ll want to add additional nitrogen to your soil now.

If you want to sex your plant to get rid of the males, a few weeks into this stage is when they’ll start showing their reproductive organs. You’ll want to separate the males to avoid the pollination of your female plants.

The Flowering Stage (8-11 Weeks)

The flowering stage lasts from eight to eleven weeks, and you’ll want to change your light cycle to 12 hours on / 12 hours off.

We’re in the final stage now! This is when your plant will begin developing resinous buds, and you’ll start seeing results from your hard work. Many strains flower in eight to nine weeks, but some (especially Sativas) can take longer.

When growing outdoors, flowering occurs once the plant receives less light during the day—i.e., when summer turns to fall. When growing indoors, you can trigger the cycle by gradually reducing the amount of light you expose your plants to from 16 to 12 hours.

The flowering stage also has three substages—these are:

  • Flower Initiation: Your plant will keep growing and develop pre-flowers. You’ll see the beginnings of buds. These are called pistils and look like little white hairs.
  • Mid-Flowering: During this time, the plant will cease growing, and you’ll notice the buds getting larger.
  • Late Flowering & Ripening: Finally, your plants will start to get sticky as the trichome density increases. Watch the pistils to see when it’s time to harvest!


Now, here are some final tips to keep in mind while your plant is going from its vegetative stage to its flowering stage:

  1. Resist pruning when your plants are flowering—this can upset their hormones.
  2. Use trellises for your plants so that the buds are supported while they develop.
  3. Plant bloom (phosphorus) nutrients are a great addition during the flowering stage.

There you have it—All the info you need to know about the growing and flowering stages of cannabis. All that’s left is to get your grow gear!

Related: Gorilla Grow Tents: Perfect for Indoor Growing


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