Average vegetation time when growing cannabis plants

Although cannabis earned the nickname ‘weed’ because it can grow in most locations and under a wide variety of climate conditions, cultivating cannabis plants is much more complicated than the average person would think.

This article will discuss the vegetative stage, average veg and flower time for cannabis, and everything you will need to do, from lighting, watering, and feeding to keep your plants strong and healthy as they enter the flowering stage.

For starters, cannabis plants grow in different stages, and during each phase of growth, they will have a different light schedule, water, and nutrient needs.

To ensure your plants produce big, resinous buds at the end of their growth cycle, keep a close eye on them during the germination, seedling, vegetative, and flowering phases.

This article will discuss the vegetative stage, average veg and flower time for cannabis, and everything you will need to do, from lighting, watering, and feeding to keep your plants strong and healthy as they enter the flowering stage.

Learn more about the vegetative stage and other stages of the marijuana life cycle when you download my free Grow Bible.

The vegetative stage of marijuana plants

Once a cannabis plant germinates and develops its first set of leaves on a relatively sturdy stem and root system, it enters the vegetative phase.

This is what most people consider the first stage of life for the cannabis plant.

This phase is when the plant concentrates on growing big and strong in preparation for the flowering phase. 

The average veg time for marijuana lasts between 4-18 weeks, depending on how big you want the plants to grow and how soon you would like them to start flowering.

During the vegetative stage, the plant will concentrate on growing and strengthening its foliage, stems, and roots.

This prepares it for carrying heavy buds once it flowers.

vegetative stage 4 weeks
Cannabis plants in vegetative stage

As the stem, roots, and foliage grow rapidly, you will have to adjust your watering, feeding, and lighting habits to ensure the plants get the right amount of light and water.

For instance, you should start watering further away from the stalk as the plant grows and the roots spread out to ensure it gets enough water.

Keep in mind; the flowering stage can begin as early as four weeks.

However, the cannabis plants will most likely be small, and the buds they yield will be equally small.

Ultimately, it’s going to be a trade-off between making the plants flower early but getting smaller buds or waiting a few more weeks for them to grow bigger and stronger and grow larger, denser buds.

Since the marijuana plant’s life cycle is greatly determined by how much light it gets during the day, you can trigger early flowering in photoperiod plants by adjusting the lighting schedule.

How long is the average cannabis vegetation time?

The vegetative cycle is crucial for the cannabis plant’s life cycle, especially if you’re looking to harvest resinous buds rather than seeds for later cultivation.

The plants will need to develop healthy leaves coupled with a strong, sturdy stem and root system to photosynthesize sunlight and support big, heavy buds’ weight. 

The average veg time will last anything from 4 weeks to 8 weeks; however, you have some control over this with photoperiod plants.

Let’s have a more in-depth look at what happens during the vegetative stage:

Marijuana vegetative stage week 4
Vegetative stage week 4
Marijuana vegetative stage week 5
Vegetative stage week 5

Once a marijuana seed is planted, either in the ground or some sort of container, it takes around 2-3 weeks to germinate and become a seedling, after which it begins vegetative growth.

During this stage, the seed will develop a tap root, its first set of fan leaves, and a complete set of leaflets.

Before you transplant the plants to a larger container or the ground, you may want to remove any stunted seedlings or seeds that haven’t fully germinated to prevent them from competing with the healthier plants for resources.

Now that there are leaves and a taproot, the taproot will drill downwards, looking for water while the leaves absorb sunlight and photosynthesize, furthering the growth process.

Marijuana vegetative stage week 7
Vegetative stage week 7
Marijuana vegetative stage week 8
Vegetative stage week 8

If you would like to start training or topping the cannabis plants, the vegetative phase is the best time to do it.

As the plant develops lateral roots that grow outwards in search of water and nutrients, start watering your plants further away from the stalk to ensure the roots stay hydrated.

If you are growing outdoors, make sure you plant the cannabis in healthy, nutrient-rich soil to support the rapid growth of the vegetative phase.

You can also supplement this by adding nutrients to your plant’s water.

For hydroponics or liquid nutrients, make sure you check pH levels and ensure they are at an optimum level (6.0 – 6.5).

Know how to perfectly time your harvest so you can maximize your yield. Download our free mini harvesting guide

Controlling the light cycle for indoor grow setups

Now that we know the average veg time for cannabis let’s get to the good stuff, lighting.

Growing your cannabis plants indoors gives you much more control over them, especially in terms of lighting.

These plants are extremely sensitive to light.

The levels of light and darkness provided during the vegetative phase determine how quickly your plant progresses to the next stage of development.

On average, cannabis will need 18+ hours of light per day during the vegetative phase.

growing cannabis indoors under light
Growing marijuana plants indoor under lights

Remember how changing the light cycle can force the plants to start flowering?

Well, as long as your indoor cannabis plants receive 18 hours of sunlight and 6 hours of darkness per day, they will remain in a vegetative state, growing bigger and stronger every day without developing any buds or flowers.

Once the plants start getting less than 12 hours of light per day, they start flowering.

However, you will have to provide just the right amount of light during this stage as too much will damage the plants, while too little light will impact the rate of photosynthesis and plant growth.

Also read “What is the best light cycle for weed plants?

Concerning average veg time, indoor cannabis grows will largely depend on how soon the grower would like them to start flowering.

If you want bigger plants and heavier buds, you will have to wait a couple more weeks to let them stay in the vegetative phase.

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However, if you don’t mind smaller plants and lighter buds, you can force them to flower early.

Give your marijuana plants a little extra love with my complete fertilizer set. Just provide your growing medium, light source, and water, and the fertilizers will do the rest.

How environmental factors affect outdoor grow setups

Growing outdoors leaves your plants at the mercy of environmental conditions.

At most, the only thing you can control is the quality of the soil you use. You won’t be able to determine the amount of light and darkness your plant receives.

It will flower naturally as the days shorten and the amount of sunlight they receive reduces. 

Starting indoors? Before you transplant your cannabis seedlings outside, ensure they receive at least 14 hours of sunlight to keep them in a vegetative state and prevent them from flowering early.

Grow marijuana outdoors in a vegetative phase
Growing outdoors leaves your plants at the mercy of environmental conditions

If you grow your cannabis plants outdoors, you also have little to no control over the humidity, temperature, and wind the plants are exposed to.

Worst case scenario, your outdoor cannabis plants will be subject to extreme environmental conditions like too much heat and light, excess rain, hailstorms, as well as pests, and plant diseases.

You’ll also deal with pollination from nearby male hemp or cannabis plants, irrigation system failures, and theft.

Some of these risks, such as extreme weather, pests, and diseases, can completely mess with your yields.

But by carefully considering your grow site and its climate before cultivation, building in quality assurance measures, and seeking expert advice throughout the entire process, you can avoid some of them and produce strong, healthy plants.

Fortunately, an outdoor grow grants your plants access to intense sunlight at no cost.

Plus, if the soil is good enough, it will have a rich tapestry of microorganisms, fungi, and minerals that will help the plant produce unique cannabinoid profiles, scents, and flavors.

How long should I veg my plants before flowering?

With 4-8 weeks of average veg time, marijuana plants can start flowering as early as four weeks.

However, just because you can force your plants to start flowering early doesn’t mean you should. Although this stage certainly isn’t as fun or exciting as the flowering stage, it is crucial.

This is when the plant experiences vigorous growth in preparation for the physical stress that comes from developing and supporting many heavy buds.

During the vegetative stage, the plants will focus on growing their stems, roots, and leaves. The taproot will dig down while the lateral roots grow to the sides, looking for water and nutrients.

A healthy set of leaves will photosynthesize more food for the plant, ensuring it has all it needs to grow strong and healthy in preparation for the flowering stage.

pre flowering stage
Vegetative stage going into flowering stage

Give your cannabis plants an average veg time of up to 18 weeks (by providing 18 hours of light and 6 hours of darkness at night.)

This practice helps their stems, roots, and foliage develop and grow. Later on, they can support big, heavy, resinous buds.

If you don’t want your plants to vegetate fully, you can force them to flower.

However, this means they sacrifice their growth so they can start flowering early. It also means you will have smaller plants and an equally smaller yield.

Triggering the flowering stage

Once the cannabis plants have been in the full vegetative phase (or however long you want them to vegetate), you can trigger the flowering stage.

Cannabis relies on photoperiods, which refer to intervals of light and darkness, to advance to the next developmental stage.

Also read “Cannabis flowering stages: indoors & outdoors

During the vegetative state, you will provide your plants with 18 hours of light and 6 hours of darkness per day to ensure they grow their roots, foliage, and stems without flowering.

To trigger the flowering stage, reduce the time spent exposed to sunlight from 18 hours per day to less than 12 hours per day.

a marijuana plant in flowering stage

Once the daily light exposure hits this threshold, the plants will start developing flowers.

For outdoor growers, your plants will start flowering once the days shorten and they start receiving less than 12 hours of light daily.

Don’t want to worry about the cannabis light cycle? Grow autoflowering marijuana seeds! They’re light-independent and grow fast – they can go from germination to maturity in less than ten weeks.

Autoflowering cannabis seeds

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Every stage of growth is equally important

Watching your plants develop big, colorful buds is undoubtedly exciting, but that stage largely depends on how the germination, seedling, and vegetative stage plays out.

If the plant doesn’t receive a specific amount of light, water, or nutrients during any of these stages, it won’t produce impressive buds.

Checking the quality marijuana plant after final stage
Checking the quality marijuana plant

The vegetative phase will determine just how big and strong the plants get. It impacts the depth and spread of their roots, the sturdiness of their stems, and the size and color of their leaves.

Do you want an impressive yield at the end of the season?

Make sure you keep an eye on your plants during the vegetative state.

Provide enough hours of sunlight, enough water, and nutrients, and you will see your plants shoot up like weeds, literally. 

FAQs about cannabis average vegtime

When does marijuana flowering begin?

The flowering period begins as soon as a cannabis plant is triggered by a lack of light. For autoflowering plants, it begins based on a set amount of time. 

How long should your veg for the best yield?

The optimal vegetation time for a cannabis plant depends on the strain. On average, most strains benefit from at least six weeks in the vegetative stage. 

How long does it take to grow cannabis plants?

Some marijuana strains can go from seed to harvest in just eight weeks. Others can take up to four months. Autoflowering strains tend to grow the quickest. 

Becoming an expert marijuana grower isn’t that complicated – you only need practice and learning. My blog can help you get started.

How was your experience with the average veg time of your cannabis plants? Please feel free to share your comments or leave questions below.

Happy growing!


Avatar for Robert Bergman

Mr Robert Bergman PhD


Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations ... See profile

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3 comments on “Average vegetation time when growing cannabis plants”

  1. Hi there,

    Thanks for your question! Most growers will flip their plants between the 8-10 week mark. One thing to consider is whether the plants have enough side branches, as this will ensure a good yield.
    And make sure the branches are sturdy enough to support a decent amount of buds as well.
    Other than that, you can technically flip them whenever you like, just make sure they have a decent size!

    Let us know if you have further questions, of course!

    Happy growing,

  2. Hi there Allen,

    You were correct, we accidentally added a wrong picture to this blog.
    I changed it immediately!

    Thanks for letting us know! 🙂

  3. Hello ….My partner and l are in our 70’s and have never tried any of your products or anyone’s product …We are not into pill taking etc but are at a lovely stage of our life where we do experience pain etc which is basically normal for our age .. We accept what life has given us but would like to be able enjoy our time together .happily and peacefully without being zonked out on medications ..I have always believed in herbs as a culinary adventure and have a lovely garden ….I am looking forward to hearing from you .Thankyou Lauren .