2 week old pot plant

Stages of the marijuana plant growth cycle

Cannabis plants, like all living things, go through a series of stages as they grow and mature. If you’re interested in cultivating cannabis, it’s especially important to understand the changes a plant undergoes during its life cycle, as each stage of growth requires different care.

Different stages call for different amounts of light, nutrients, and water. They also help us decide when to prune and train the plants. Determining a plant’s sex and overall health rely on stages of growth as well.

How long does it take to grow a marijuana plant?

Generally speaking, it takes anywhere from 14-32 weeks, or about 4-8 months, to grow a weed plant.

The biggest variability in how long a marijuana plant takes to grow will happen in the vegetative cycle—if you’re growing indoors, you can force it to flower after only a few weeks when it is small, or after several weeks when it is big. If you’re growing outdoors, you’re at the whim of the seasons and will have to wait until fall to harvest. The plant will develop buds in the last 8-11 weeks.

The life cycle of cannabis can be broken down into four primary stages from seed to harvest:

  • Germination (5-10 days)
  • Seedling (2-3 weeks)
  • Vegetative (3-16 weeks)
  • Flowering (8-11 weeks)

Seed germination (5-10 days)

Light cycle: 18 hours of light

The first stage of life for a cannabis plant begins with the seed. At this point, your cannabis plant is dormant, patiently waiting for water to bring it to life.

You can observe the quality of the seed by its color and texture. The 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.

To begin growing from a seed, learn more about germination here. This stage can take anywhere between 5-10 days.

Once your seed has popped, it’s ready to be placed in its growing medium. 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 needed for the plant to become healthy and stable.

As the roots develop, you will begin to see the first iconic fan leaves grow, at which point your cannabis plant can be considered a seedling.

Seedling stage (2-3 weeks)

Light cycle: 18 hours of light

When your plant becomes a seedling, you’ll notice it developing more of the traditional cannabis 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 (1, 3, 5, 7, etc.). A mature cannabis plant will have between 5-7 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 very 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.

Vegetative stage (3-16 weeks)

Light cycle: 18 hours of light

The vegetative stage of cannabis is where the plant’s growth truly takes off. 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.

Spacing between the nodes should represent the type of cannabis you are growing. Indica plants tend to be short and dense, while sativas grow lanky and more open in foliage.

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 so the roots can stretch out and absorb water more efficiently.

Vegetative plants appreciate healthy soil with nutrients. Feed them with a higher level of nitrogen at this stage.

Flowering stage (8-11 weeks)

Light cycle: 12 hours of light

The flowering stage is the final stage of growth for a cannabis plant. Flowering occurs naturally when the plant receives less than 12 hours of light a day as the summer days shorten, or as the indoor light cycle is shortened. It is in this stage that resinous buds develop and your hard work will be realized.

If you need to determine the sex of your plants (to discard the males), they will start showing their sex organs a couple weeks into the flowering stage. It’s imperative to separate the males so they don’t pollenate the flowering females.

There are a number of changes to consider once your plant goes from its vegetative stage to flowering:

  • Your plants shouldn’t be pruned after three weeks into the flowering stage, as it can upset the hormones of the plant.
  • Plants should be trellised so that buds will be supported as they develop.
  • Consider feeding plants with blooming nutrients.

What week of flowering do buds grow the most?

Buds typically grow the most toward the end of the flowering cycle, around week 6-7. You probably won’t notice much budding out at the beginning of flower, and it will slow down toward the end of the cycle, when buds become fully formed.

Once the buds have reached full maturation, it’s time to harvest.

This post was originally published on July 18, 2017. It was most recently updated on January 17, 2020.

It’s important to understand the changes a growing cannabis plant undergoes during its life cycle, as each stage of growth requires different care.

Do these seedlings look ok for 2 weeks?

  • Dec 20, 2010
  • #1
  • Shootz
    New Member

    This is my first grow, they sprouted on 12/7. I am worried that I am under watering them I usually water every 2 days. Lately the soil is getting very crusty and dry should i water them more?

    Medium- FF light warrior 160z cups
    Strain- 5 nirvana WW, 2 freebie autos
    Humidity- 40-50%
    Temp- 75-80 light on 70-75 light off
    light-4 26w 5000k CFLs on 20/4 light cycle

    • Dec 20, 2010
  • #2
  • AK GreenLover
    New Member

    They don’t look to shabby for a few weeks of age. Mine are that size by the first week, but at least they look decently healthy.

    You do want a good wet dry cycle, but it’s really BAD if you let your soil dry out to much before watering. If your soil is to dry most of your water will run right through instantly. Your soil wont hold as much moisture as it should.

    I grow with CFl’s a lot and have never bothered with 5000k in veg. I can say I tried them once but didn’t get the growth I wanted and was used to. I would use 1 x 2700k and 4 x 6500k in my veg box. I did however find a use for my 5000k bulbs. I use them in the last few weeks of flowering, and it seems to help a little with size. Not anything to write home about but I did go hmm on my last grow. So I will be using them again late in flowering next time.

    The only other thing I would recommend you do is kill the 24 / 0 light schedule with a massive axe. 24 / 0 is excellent for clones or the first few days of veg but thats it. If you must pump them with so much light at least go with 20 / 4 instead. It will promote better root growth. Thats probably the biggest reason why your two week plants are the size of my less then 1 weekers on an average grow.

    Anyways over all good job! Keep up the good work.

    • Dec 21, 2010
    • Thread starter
    • #3
    New Member
    • Dec 21, 2010
  • #4
  • hc5guam
    New Member
    • Dec 21, 2010
  • #5
  • MrsLonely
    New Member
    • Dec 21, 2010
  • #6
  • Thew1sest
    New Member

    Yeah just make sure you’re not over watering/ feeding the little girls. In the beginning they’ll take to minor changes and show it quite well how they’re feeling. You seem to have the light spectrum and watering down, (Just make sure to not over/ under water). Letting them just grow, and they’ll do just fine. Marijuana is a resilient plant and can thrive in many conditions that most think it would not.

    • Dec 22, 2010
    • Thread starter
    • #7
    New Member
    • Dec 22, 2010
  • #8
  • Thew1sest
    New Member
    • Dec 22, 2010
  • #9
  • New Member

    if you going to put them under intense light. than is best to water them before doing so if is time for them to be water. than after that start put them under the intense light, after that.

    this way you’ll be safe and not get the top dry out. seedling won’t be growing to much untill they take root. so that’s not untill like atleast 3-5 day after they rooted well and than shoot to cum up. by than you is still not too late to start putting intense light on them.

    using a 400 hid light for right now. it won’t hurt. and the leave might grow alittle better. but the root hasn’t take place yet. so there no reason to be hurry. is not going to start growing fast untill there is enough root.
    so it won’t hurt but is not necesarry to to use that much light at this put because it just wont be growing all that much without now root. if your plant is dying without light that yes give light to them. otherwise i say save some money eletrictricity and wait untill they are ready. it won’t hurt by giving plant alot of light right now, but it wil only help a little more than with cfl bulb. is really up to you what you want to do. if you want the plant to grow fast right away than do it, if you can wait i say wait. wither way will work but if you want to save money and not have to wait too long. you don’t have to put to much light on it at this point, not untill i say a good 13 more days.

    so is really bad if you want to grow but not want to use to much electricity at this point. cause 13 more days is still alot of days of light if you talking hids. cfl now is only about a function of the price but is no wrong or right anwser here. if you can afford it that i say try it once and try cfl next tiem and see what’s work best and choice if you want to save money for the extra growth during this time. than go with that later on your growing years.

    This is my first grow, they sprouted on 12/7. I am worried that I am under watering them I usually water every 2 days. Lately the soil is getting very…