Everything you need to know about the 6 stages of cannabis growth. From selecting seeds to determining plant sex. Knowing where your cannabis plants are in their life cycle will dictate when to prune, train, and harvest your plants. Learn more about marijuana growth stages today. Starting cannabis from seed is an affordable and fulfilling way to start growing. It all starts with germinating cannabis seeds, followed by creating the ideal warm, humid environment for seedling growth. Giving your seeds (and then the seedings) the best support from the very start, you'll set yourself up for success
The Stages of Cannabis Growth
Cannabis growth is made up of a series of stages that plants undergo during their lifecycle. Each stage during the cannabis cultivation process requires its own unique demands, including different levels of light, water, and nutrients.
It can take anywhere from 4 to 8 months to grow a cannabis plant, this varies based on where you’re growing. If you have an indoor grow room, your plant has the ability to flower after only a few weeks!
The quality of your plant depends on your knowledge of the cannabis growth stages and the lifecycle of your plants.
Cannabis Growth Timeline
1. Germinating: 1-7 days
2. Seedling: 2-3 weeks
3. Vegetative: 2-8 weeks
4. Pre-Flowering: 1-2 weeks
5. Flowering: 6-8 weeks
1. Germinating Seeds
2. Seedling Stage
3. Vegetative Growth
How to tell if your plant is a male or female
Female: Two pistils (the pistil contains the reproductive parts of a flower) will be growing on the buds (flowers grow above these leaves, one cluster on each side).
Male: Small green sacs full of pollen will be seen on the node areas.
- If there is a high color ratio of white to red pistils your cannabis will provide a euphoric THC high.
- If the color ratio is more red to white, your cannabis will provide a calmer, CBD-stoned feeling.
- If you harvest once half the trichomes are opaque and the pistils haven’t turned brown, your cannabis will provide a balanced THC/CBD high.
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4 stages of marijuana plant growth
Cannabis plants go through a series of stages as they grow and mature, and those different growth stages call for different amounts of light, nutrients, and water.
It’s important to know these stages and how long each lasts to know what the plant needs and when. Knowing where your cannabis plants are in their life cycles will dictate when to prune, train, and trellis your plants, and when to harvest.
How long does it take to grow a marijuana plant?
Generally speaking, it takes anywhere from 10-32 weeks, or about 3-8 months, to grow a weed plant from seed to harvest. It’ll be quicker if you start with a clone or an autoflower seed.
The biggest variability in how long a marijuana plant takes to grow will happen in the vegetative stage—after the seedling phase and before flowering.
If you’re growing indoors, you can force a weed plant to flower after only a few weeks when it’s small or after several weeks when it’s big.
When growing outdoors, you’re at the whim of the seasons and will have to wait until the sun starts to go down in the fall for plants to flower, and then to harvest.
However, one way outdoor growers can control the flowering cycle is by using light deprivation techniques.
What are a weed plant’s growth stages?
The growth stages of marijuana can be broken down into four primary stages from seed to harvest:
- Germination (3-10 days)
- Seedling (2-3 weeks)
- Vegetative (3-16 weeks)
- Flowering (8-11 weeks)
Cannabis seed germination
Seed germination length: 3-10 days
Marijuana light cycle: 18 hours a day indoors; full, direct sun 6 hours a day outdoors
The first marijuana plant stage begins with the seed. A cannabis seed should feel hard and dry, and be light- to dark-brown in color. An undeveloped seed is generally squishy and green or white in color and likely won’t germinate.
Once your seed has germinated, or sprouted, it’s ready to be placed in a growing medium, like soil. The tap root will drive down while the stem of the seedling will grow upward.
Two rounded cotyledon leaves will grow out from the stem as the plant unfolds from the protective casing of the seed. These initial leaves are responsible for taking in sunlight so the plant can grow healthy and stable.
As roots develop, the stalk will rise and you’ll begin to see the first iconic fan leaves grow, at which point your cannabis plant can be considered a seedling.
Can you speed up the germination process?
No. Cannabis seeds are delicate and don’t like to be moved around. They need a warm environment that doesn’t fluctuate in temperature, and not too much water. Once you put them in soil, we recommend leaving them be.
Quality seeds typically have high germination rates, but you may get some duds that don’t sprout. Let them do their thing; helping them along can decrease their change of survival.
Seedling stage in cannabis plants
Seedling stage length: 2-3 weeks
Marijuana light cycle: 18 hours a day indoors; full, direct sun 6 hours a day outdoors
When your marijuana plant becomes a seedling, you’ll notice it developing the traditional cannabis fan leaves. As a sprout, the seed will initially produce leaves with only one ridged blade.
Once new growth develops, the leaves will develop more blades, or “fingers” (3, 5, 7, etc.). A mature cannabis plant will have between 5 or 7 blades per leaf, but some plants may have more.
Cannabis plants are considered seedlings until they begin to develop leaves with the full number of blades on new fan leaves. A healthy seedling should be a vibrant green color.
Be careful to not overwater the plant in its seedling stage—its roots are so small, it doesn’t need much water to thrive.
At this stage, the plant is vulnerable to disease and mold. Keep its environment clean and monitor excess moisture. Be sure to give it plenty of light.
Even if growing outdoors, a lot of growers will start their seeds inside under an artificial light to help them through this delicate stage of marijuana growth.
If you buy a clone from a grower or breeder it will be a seedling, so you can skip the seed germination phase.
Vegetative stage in cannabis plants
Vegetative stage length: 3-16 weeks
Marijuana light cycle: 18 hours a day indoors; full, direct sun 6 hours a day outdoors
The vegetative stage of cannabis is where the plant’s growth truly takes off, and it typically lasts 3-16 weeks. At this point, you’ve transplanted your plant into a larger pot and the roots and foliage are developing rapidly. This is also the time to begin topping or training your plants.
Be mindful to increase your watering as the plant develops. When it’s young, your plant will need water close to the stalk, but as it grows the roots will also grow outward, so start watering further away from the stalk in the soil so roots can stretch out and absorb water more efficiently.
Vegetative plants appreciate healthy soil with nutrients. Feed them with a high level of nitrogen at this stage.
Cannabis plant flowering stage
Flowering stage length: 8-11 weeks
Marijuana light cycle: 12 hours a day indoors; full, direct sun 6 hours a day outdoors
The flowering stage is the final stage of growth for a cannabis plant. This is when plants start to develop resinous buds and your hard work will be realized. Most strains flower in 8-9 weeks, but some can take even longer, especially some sativas.
Outdoors, flowering occurs naturally when the plant receives less light each day as summer turns into fall.
Indoor growers can trigger the flowering cycle by reducing the amount of light marijuana plants receive from 18 to 12 hours a day.
There are three subphases of the flowering stage:
- Flower initiation (week 1-3): The plant will continue to grow and females will develop pre-flowers—pistils, or white hairs, will grow out, which are the beginnings of buds.
- Mid-flowering (week 4-5): The plant itself will stop growing and buds will start fattening up.
- Late flowering/ripening (week 6 and on): Trichome density will increase and plants will get very sticky; keep an eye on the color of the pistils to tell when to harvest.
There are a number of changes to consider once plants go from the vegetative stage to the flowering stage:
- Don’t prune when plants are flowering, as it can upset their hormones
- Plants should be trellised or scrogged so buds will be supported as they develop and air can flow through plants
- Consider giving plants bloom or phosphorus nutrients
What does the pre-flower stage look like?
Pre-flowers are the beginnings of cannabis plant sex organs. If you’re growing regular seeds, you’ll likely have a mix of male and female plants and will need to determine the sex of your plants to discard the males. It’s imperative to separate males so they don’t pollinate the females.
Pre-flowers appear at the nodes of the plant, where a branch grows out of the main stalk. Females will develop an oval-shaped bract with hairs or pistils sticking out, while males will develop round pollen sacs.
Learn more about pre-flowers and cannabis plant sexing in our anatomy article.
How to tell when a cannabis plant is ready to bloom
When growing outdoors, weed plants will start flowering, or blooming, after the summer solstice, when the daily amount of light starts to decrease. Plants will start developing pre-flowers, as mentioned above, telling you that flowering has initiated.
When growing indoors, growers make the decision to force blooming or “flip” plants into flower by cutting off the amount of artificial light they receive.
What to do when cannabis plants flower early or late
The amount of time it takes a plant to finish, or be done flowering and ready for harvest, will depend on what strain it is. Typically, indicas finish flowering early and sativas finish flowering late.
Note information from the breeder when you buy seeds to grow to get a sense of how long it takes to flower. You may have to harvest some plants early and some late depending on their finish times.
For late-flowering strains, keep an eye on the weather and make sure cold weather doesn’t ruin your plants before they finish.
When do buds grow the most?
Buds typically grow the most toward the end of the flowering life cycle. You probably won’t notice much budding out at the beginning of the flowering stage, and it will slow down toward the end of the cycle, when buds become fully formed.
Once buds have reached full maturation, it’s time to harvest your marijuana. How long it takes to harvest buds depends on many factors, including harvesting methods and how many plants you harvest.
How long can a marijuana plant live?
Weed plants are annuals, meaning they grow and live for one season and then die. Wild cannabis plants grow seeds and drop them when they die, which will grow into new plants the following year.
When harvesting, plants are cut down and die in order to get their buds. New seeds need to be planted in order to grow more plants.
If left unharvested, weed plants will eventually wither and rot within a few months after the peak flowering phase.
When should you grow marijuana?
If you’re growing outdoors in the Northern Hemisphere, growers usually get their seeds between February and April and start germinating seeds by the end of April.
Many start growing seedlings inside in a more controlled environment because seedlings are more delicate, and then put the seedlings in the ground outside once they’re a little bigger and the weather is warmer.
If you’re growing clones or autoflowers, you have a grace period of another month or so. Plants usually need to be outside, in the ground, by the end of June.
Harvesting happens sometime between September and November. This depends on your local climate, as well as the weather that particular year—one year it could be the end of September, the next, end of October; growers in the Pacific Northwest will have to pull down their crops earlier than those in Northern California because of cold weather.
If you’re growing weed indoors, you can grow whenever you like. Keep in mind that the outside environment will affect your grow space—you may need to add heaters in the winter or fans and ACs in the summer.
Other than that, you can start seeds whenever you like and flip them into flower whenever you like, depending on how big you want the plants.
Important dates for growing marijuana outdoors
Many growers begin germinating seeds as early as February and March in order to have big plants come harvest time, but the Spring Equinox is a good reminder that it’s time to kick off the outdoor growing process and start germinating your seeds if you haven’t already.
Many farmers wait until after Mother’s Day in May to put their plants outside. Just make sure all of your plants are outside by the Summer Solstice at the latest.
The weather will start to turn and the sun will begin descending in the sky as your plants fatten up with sweet, sticky buds. It might be tempting, but the Fall Equinox is about when to start harvesting. It’ll depends on your climate and the year—it could happen a little before or after.
Everything should be cleaned up, dried, and curing by Thanksgiving, and in some places, even by Halloween.
As winter approaches, it’s prime time to make your own cannabutter, topicals, or tinctures with all that trim from the harvest. Kick your feet up, relax, and hunker down for the cold, it’s been a long growing season!
Notes on marijuana growth phases
We can’t stress enough that the timeframes in the above graphic are ranges of time for the Northern Hemisphere. You’ll need to adjust them based on your specific region and local weather and climate.
Be sure to keep a grow journal to track the progress of your plants. Looking back on your notes will help you learn from mistakes and maximize the quality and quantity of your buds next year.
Take meticulous notes on when and how you perform each step, noting:
- How much water you give plants, and at what intervals
- Nutrient amounts
- When you top and prune
Pictures will also give you a better sense of how your plants look along the way.
Grow Guide: How to Start Cannabis from Seed
Starting cannabis from seed is an affordable and fulfilling way to start growing. It all starts with germinating cannabis seeds, followed by creating the ideal warm, humid environment for seedling growth.
Giving your seeds (and then the seedings) the best support from the very start, you’ll set yourself up for success come harvest. Here are the basics to growing cannabis from seeds.
Where to Find Cannabis Seeds
At this point, there are hundreds of different online options for sourcing cannabis seeds . If you are growing indoors, the world is your oyster, as many websites are willing to ship nationally (or even internationally). Plus, if you master the indoor environment, you can recreate perfect conditions for even the most demanding of strains.
For those growing outdoors, try to locate a local breeder who also cultivates outside. These cultivars will be adapted to your unique climate and will likely produce better results.
No idea where to start? Seed Finder is an excellent resource for sourcing specific genetics and breeders in your area. But this is just one place among many in today’s weed-friendly world.
How to Germinate Cannabis Seeds
What You’ll Need:
- Cannabis seeds
- Paper towel
- Plate or tray
- Ziplock bag
- Heating mat (optional)
The first step to growing cannabis from seed is learning how to germinate them. Place cannabis seeds on a sheet of paper towel, laid on top of a tray. Dampen the towel with water so it’s wet but not soaking.
Fold the towel in half to cover the seeds, and enclose it inside a Ziploc bag. Place the entire tray on a heating mat, the top of a fridge or other warm area of your house. Cannabis seeds germinate between 71 to 77°F (22–25°C).
Check back every day for signs of life. If your seeds are viable, they should sprout within a week. If you are still waiting for a few to emerge after a week, toss those and begin again. If no seeds have sprouted, your seeds are no longer viable.
Ed Rosenthal recommends soaking seeds for 12 hours before germination. His formula uses water, a cannabis rooting solution and hydrogen peroxide.
This solution is a good option for commercial and large scale growers, as it reduces the risk of fungal infection and encourages rapid sprouting. Compost tea is another excellent option for a natural alternative.
Ideal Conditions for Cannabis Seeds and Seedlings
What You’ll Need:
- Germinated Cannabis Seeds
- Potting Mix (or Root Riot Plant Cubes )
- Propagation Tray with Dome
Once germinated, you must carefully move these tiny seeds into the soil or soilless growing medium like Root Riot Plant Cubes. When you start cannabis from seed, the aim is a warm and relatively humid environment.
Starting Cannabis With Soil
If using soil, choose an organic potting mix suitable for seeds and starts. Water soil mixture before use, and fill potting containers that have a drainage hole. Avoid pellets that are commonly sold at garden centers, as they don’t retain moisture well, and it’s challenging for cannabis roots to break free of the netting.
Using a popsicle stick, tweezers or a toothpick, lower the germinated seed into a premade hole roughly two the three times the height of the seed. As you gently fill in the hole, be careful not to damage the sprout.
Starting Cannabis for Hydroponics
For hydroponics, you’ll want to use Rockwool cubes or Root Riot Plant Cubes. These come pre-cut into perfect starter plugs, often with a hole in the middle for the seed.
Before use, soak the cubes in water and rooting solution until they are wet but not dripping. Gently lower the germinated seed into the hole using a popsicle stick, tweezers or a toothpick. Be extremely careful not to damage the early sprout.
Whatever option you choose, keep the seedlings at a consistent temperature: 68 to 77°F (20 to 25°C). Depending on where you live, a heating mat may be necessary. Use a propagation tray with a clear dome to trap the humidity in, but open up once a day to encourage a bit of airflow.
Lighting Requirements for Cannabis Seedlings (& How to Eliminate Stretch)
Seedlings and starts require 16 hours of light a day and eight hours of dark. You can even bump this up to 24 hours a day, and the seedlings will continue to eat it up.
What kind of grow light do you need for this early stage of development? Not the same capacity you’ll need for veg and bloom. Higher wattage types of HID lights (Metal Halide and High-Pressure Sodium) are far too powerful for sensitive seedlings.
Most growers use a simple LED grow light or a CFL fixture. Ed Rosenthal recommends 40 to 60 watts per square foot.
While these may not be entirely enough for veg and bloom, they produce enough light for seedlings without the added heat. This means you can place the lights close to the tops of the seedlings.
Place lights as close as possible to the tops of the starts, without raising the temperature over 77°F. You want seedlings to get enough light without burning them.
The goal is to avoid early stretching in your small cannabis seedlings. Healthy seedlings are short and wide, not tall and skinny. Stretching is when the sprout reaches tall for the light without putting out leaves.
Typically, under outdoor conditions, plants remain short for the first few weeks as they focus energy on building structure and root development. Stretching inside demonstrates the seedling is not getting enough light. The light source is either not intense enough or too far away.
When to Transplant Cannabis Seedlings
The primary goal for starting cannabis seeds in small pots is to encourage healthy and strong root development. Once the seedling has three to four sets of leaves, begin checking root development. This will likely be three or more weeks after germination.
Another telltale sign it’s time to transplant is when you notice roots begin to creep out from the drainage holes. If working with Rockwool, a key indicator it’s time to transplant is when the roots begin to outgrow the cube. A plant’s growth trajectory slows down if it is root-bound. If the roots have consumed the available space, it’s time to move up a size.
Cannabis Seedlings From Germination to Transplanting
Starting cannabis from seed gives growers access to a much larger genetic pool than what you can find locally from a clone supplier. Plus, if you’ve got the time to invest, it’s a much more affordable way to grow cannabis. Finally, if you are already set up with a veg and bloom room, you have everything you need to get started from seed.