Grow Guide: How Long Vegetative Stage Of Weed Last

The vegetative stage of a cannabis plant’s life is like a roller coaster ride, filled with exciting ups and downs, twists and turns. Understanding the meaning and length of the vegetative period is crucial for any grower looking to cultivate a successful crop, as it plays a significant role in determining the plant’s overall health, size,…

Grow Guide: How Long Vegetative Stage Of Weed Last
Nenad Nikolic

Author: Nenad Nikolic

Publish Date: July 13, 2023
Last Update Date: September 13, 2023

What is the Vegetative Stage of Cannabis Plants?

What is the Vegetative Stage of Cannabis Plants

The vegetative stage for marijuana plants is a crucial phase in a life cycle where it’s all about growth.

Imagine this stage as the energetic teenager of the cannabis world – bursting with vitality, eagerly reaching for the sky, and vigorously developing its robust structure.

During this time, our beloved green darlings focus on establishing their roots, sprouting branches, and unfurling leaves.

It contrasts to the other plant stages as cannabis seeds germination, seedling, and flowering, where our plants have other priorities in their botanical minds. 

The vegetative growth phase sets the stage for a bountiful harvest, as a strong and healthy plant will reward us with abundant precious buds.

While this phase is critical for both male and female plants, it’s essential to keep an eye out for signs that will help you identify their sex.

Early identification allows growers to separate male plants from females, preventing accidental pollination.

When Does the Cannabis Vegetative Stage Start?

When Does the Cannabis Vegetative Stage Start

The vegetative period is like the adolescence of plant life, a time of rapid cannabis growing and endless potential.

This exciting start of the vegetative phase of cannabis is right after the seedling stage when our plants start to grow their baby leaves and develop true leaves with serrated edges.

To pinpoint the exact moment when the vegetative stage starts, keep an eye out for the emergence of the third set of true leaves.

That is when our young plant officially enters the vegetatition, and its growth accelerates like a rocket blasting off into space.

During this stage of growth, the cannabis focuses on developing a robust root system and a strong, sturdy structure.

Our plant is building a solid foundation to support the lush canopy of nugs that will come later in the blooming stage.

As the plant stretches towards the sky, it spreads its branches, creating more nodes and leaf sites for future nugs development.

It’s essential to provide optimal conditions for our plants during this stage, as any issues or stress during the vegetative period can impact the overall health and yield of the plant.

By nurturing our plants and guiding their optimal growth, we can set the stage for a bountiful harvest later on.

How Long Does the Vegetative Stage of Weed Last?

How Long Does the Vegetative Stage of Weed Last

Ah, the million-dollar question!

The length of the vegetative period is like a dance, choreographed by a combination of factors such as strain, growing weed conditions, and a grower’s personal preferences. 

Some smaller plants of weed, like speedy salsa dancers, may race through the vegetative and flowering stages in a few weeks.

On the other hand, other plants, akin to a slow waltz, can take their sweet time, stretching the vegetative period to several months.

The laid-back Indica strains, tend to have a shorter vegetative period, lasting around 4-6 weeks.

Meanwhile, the tall and lanky Sativa strains can take 6-10 weeks or more to strut their stuff.

Don’t forget the unique autoflowering plants, the rebellious teens that march to the beat of their drum, often completing their entire cycle in just 8-12 weeks!

Basic Grow Room Requirements for the Vegetative Growth

Basic Grow Room Requirements for the Vegetative Growth

Let’s talk about setting the stage for our flourishing plants.

Like any excellent performance, our plants need the perfect environment to shine.

Enter the grow room, a haven where our vegetative starlets can stretch their limbs and bask in the warm embrace of artificial sunlight.

To provide optimal conditions for plant growth, we need to consider factors like temperature, humidity, and air circulation.

Our botanical divas prefer temperatures between 70-85°F (21-29°C) and 40-70% humidity levels.

A well-ventilated space is also essential, ensuring our plants can breathe easily and preventing unwanted mold gatecrashers.

Regarding the growing medium, our plants aren’t too fussy.

Whether it’s soil, coco coir, or a hydroponic setup, the key is providing a stable foundation for optimal root growth and nutrient absorption.

Ideal Light Cycle for Cannabis Vegetative Stage

Light is the lifeblood of our plants, fueling their growth like a potent elixir.

The vegetative period is about soaking up those rays as our plants bask in a sunlit symphony that orchestrates their development.

To keep our green starlets happy, we should aim for 18 hours of light and a 6 hour rest period (18/6 light cycle).

Think of the cycle of light as a perfectly choreographed performance, with our plants dancing to the rhythm of the sun (or grow lights, in this case).

Different Types of Lighting

Different Types of Lighting

When it comes to grow lights indoors in grow room or grow tent, variety of lights is the spice of life. 

Our plants are like connoisseurs of light, relishing the different spectrums that cater to their every whim week by week. 

From the full spectrum LED and the intense High-Pressure Sodium (HPS) to the cool Metal Halide (MH) and the energy-efficient Compact Fluorescent (CFL), there’s a light for every stage of our plants’ journey. 

As our plants transition through their life cycle indoors, they crave different light spectrums.

During the seedling stage, they desire a cool blue glow.

In the vegetative period, they long for blue hues.

Plants in the first weeks of the vegetative stage are still young and may suffer dehydration from very high temperatures so check this as a first measure.

Plants in the veg stage do not require high-intensity light and may be affected negatively if the light intensity is very high.

Regarding flowering phase, they yearn for the warm embrace of red light.

Like a maestro conducting an orchestra, we must adjust the light spectrum to match our plants’ ever-changing needs.

Nutrients Requirements of Cannabis Plants in Vegetative State

Nutrients Requirements of Cannabis Plants in Vegetative State

Our cannabis plants are like gourmet diners craving various nutrients to satiate their voracious appetites.

During the vegetative period, they require a blend of macronutrients, including nitrogen (N), phosphorus (P), and potassium (K), as well as micronutrients like calcium, magnesium, and iron.

Imagine each nutrient as a distinct flavor that, when combined, creates a gastronomic masterpiece.

Nitrogen is the main course, fueling the growth of leaves and stems.

Phosphorus plays a supporting role, helping to develop strong roots, while potassium adds the finishing touch, assisting with water and nutrient uptake.

As experienced growers, we must serve the perfect nutrient balance to ensure our plants can indulge in a fine dining experience.

Over or underfeeding can lead to nutrient deficiencies or toxicities, so keeping an eye on our plants’ health is crucial especially during the late veg stage.

Finding the perfect nutrient balance is crucial for the end goal: a bountiful harvest.

What is Ideal Nitrogen Percentage Required?

The three main nutrients that are most important for cannabis are nitrogen, phosphorus and potassium usually abbreviated as NPK.

The best nutrients for vegetative period are high in nitrogen and low in phosphorus.

This is because, during the vegetative period, plants are mostly focused on growing leaves and stems, rather than flowers.  

Nitrogen, the star player of the veg stage, is crucial for the growth and development of our cannabis plants.

In their vegetative banquet, our plants desire a high percentage of nitrogen, around 2-5% of the total nutrient mix.

This nitrogen-rich feast will fuel our plants’ growth and ensure they develop the strong, healthy structure needed for a bountiful harvest.

How Long Should You Keep Your Marijuana Plants in a Vegetative Stage?

How Long Should You Keep Your Marijuana Plants in a Vegetative Stage

Deciding how long to keep your plants in the vegetative period is like choosing the perfect outfit for a night out – it’s all about personal style and preference.

As a grower, you can determine the ideal vegetative period to achieve your desired plant size and yield.

Generally, the longer our plants luxuriate in the veg stage, the larger they’ll grow, like botanical giants reaching for the heavens.

However, don’t forget that plants can nearly double in size during the flowering phase.

So, it’s essential to consider your growing space and avoid creating a jungle of tangled limbs and leaves.

The Benefits of Keeping a Plant in a Vegetative Stage

Allowing our plants to linger in the vegetation can be like savoring a fine wine, taking the time to appreciate its complexity and depth.

A more extended vegetative period can encourage more robust growth, leading to a sturdy plant structure.

It can also allow for more effective training and pruning, giving you greater control over your plant’s final shape and size.

How To Tell If Your Cannabis Is Ready For The Flowering Stage?

How To Tell If Your Cannabis Is Ready For The Flowering Stage

Timing the transition to the blooming phase is like waiting for the perfect moment to drop the beat on a dance floor.

Our plants will give us subtle cues when they’re ready to strut their stuff and start flowering.

One telltale sign is when our plants have reached around half their desired final height.

Another hint is the appearance of pre-flowers, tiny structures that emerge at the nodes, heralding the onset of the blooming stage.

How Tall Do Autoflower Plants Get In Vegetative Phase

How Tall Do Autoflower Plants Get In Vegetative Phase

Autoflower plants are the compact sports cars of the cannabis world, boasting a sleek and efficient design.

In the vegetative period, these petite powerhouses typically reach 12 to 24 inches (30-60 cm).

However, some autoflower strains may still surprise us with their vertical aspirations, stretching up to 36 inches (90 cm) or more.

Don’t be fooled by their diminutive stature, though.

These small plants can pack a punch, producing impressive yields despite their modest size.

Their ability to grow quickly and efficiently is a testament to their genetic makeup, which combines the best traits of their cannabis cousins, such as indica and sativa, with the hardy resilience of ruderalis.

One of the key factors influencing the height of autoflowers during the vegetation phase is the amount of light they receive.

Because autoflowers are not dependent on a specific cycle of light to initiate blooming, they can be grown under various light schedules, such as 12/12, 18/6, 20/4, or even 24/0.

Adjusting the light can impact their overall height and grow cycle.

Beyond schedules, other factors that can influence the height of autoflowers during their veg phase include the growing environment, nutrient availability, and the grower’s personal touch.

By providing optimal conditions and nurturing touch, we can help our autoflowers reach their full potential, regardless of size.

When is Time for Training Marijuana Plants In Veg Stage?

Training your plants during their vegetative period is like coaching a promising athlete, helping them develop strength, flexibility, and endurance.

The key to successful training lies in timing and technique.

Generally, the ideal time for training begins early when the plant is around 3 to 4 weeks old, exhibiting at least 4 to 6 nodes and a healthy, vigorous growth pattern.

As our plants progress through the vegetative period, we can employ various training techniques to give your plants better potential, from gently guiding plants to grow to more assertive methods that encourage the development of a sturdy, efficient structure.

If left untrained, in their vegetative period, plants may grow haphazardly, resulting in an unproductive and unwieldy plant, making it crucial to know when it’s time to train them.



Pruning is the careful art of removing selected leaves and branches from our cannabis plants to promote better airflow, light penetration, and overall plant health.

By selectively snipping away certain plant parts, we can help it focus its energy on the areas that matter most, like the main cola and nug sites.

Begin pruning during the vegetation period when the plant has developed at least 4 to 6 nodes.

Remove any dead, yellowing, or damaged leaves and any lower branches that aren’t receiving ample light.

When pruning, always use clean, sharp scissors or pruners to avoid causing stress or injury to the plant.

Remember, moderation is key—over-pruning can cause more harm than good.



Topping is a powerful training technique that involves removing the top growth tip of the plant, encouraging it to develop multiple main colas instead of just one.

That can lead to a more even canopy, better light distribution, and increased yields.

Start topping during the vegetative period when the plant has at least 4 to 6 nodes.

Simply snip off the top growth tip just above a node to top the plant.

After topping, the plant will redirect its energy to the remaining growth tips, promoting the development of a bushier, more robust structure.



Trimming is the process of removing excess foliage from our cannabis plants to encourage better airflow and light penetration.

That can help prevent mold and pests while allowing the plant to focus its energy on developing the choicest bud sites.

Begin trimming during the vegetative period, focusing on the lower leaves and branches that receive little to no light.

As the plant grows, trim away leaves that block light from reaching the bud sites.

When trimming, always use clean, sharp scissors or pruners to avoid causing stress or injury to the plant.


How often should I water my weed plants in vegetative period?

Water your plants in the vegetative stage every 2-3 days, maintaining consistent moisture in the growing medium.

How long to keep weed in vegetative growth stage?

Cannabis growers should keep their plants in the vegetation period for a duration that ranges from 3-8 weeks, depending on factors like strain, growing conditions, and grower preference.

How long does weed stay in vegetative period?

Weed stays in the vegetative period until the grower switches the lights to induce flowering, typically by changing the schedule of light to 12 hours of light per day followed by 12 hours of darkness.

When to switch from vegetative to blooming stage?

Switch from the vegetative phase to blooming phase when the plant has reached half its desired height, considering factors like plant size, available grow space and desired yield.

How to speed up veg growth?

Speed up veg growth by ensuring optimal conditions, including proper lighting, temperature, humidity, nutrients, and water.

Can cannabis plants stay in a vegetative period forever?

Cannabis plants can theoretically stay in the vegetative period forever if the appropriate cycle of light (18/6 or 24/0) is maintained, but this is not practical for most growers, as the goal is typically to induce flowering and harvest nugs.

Why are mother plants kept in a vegetative state?

Mother plants are kept in a vegetative period for cloning purposes, genetic preservation, size control, and rapid production of clones.

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