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Mastering Vegetative Stage In Cannabis Plants

The vegetative stage occurs between the germination and the flowering period. After the seeds complete their germination, the seedling development phase will last around 2 weeks. Seedlings begin the vegetative growth period once a solid root system has formed and leaf growth has increased substantially.

Within this period, there are some requirements for your plant growth. You need to offer them the right light, nutrients, watering, pH level, and temperature.

This article will share with you more detailed information. Let’s dive in!

What Is The Marijuana Vegetative Phase?

The vegetative stage is the phase of the growth cycle that occurs after the germination but before the flowering.

Vegetative stage of cannabis plants
Vegetative stage of cannabis plants

Seedlings will sprout from the soil once the marijuana seeds have germinated. A small branch and two circular cotyledons distinguish these immature seedlings. The first genuine leaves will appear later.

Seedlings will begin to grow and form a significant amount of fan leaves during the next 2 to 3 weeks. The vegetative period starts at this time.

The length of vegetative time depends on the origins of the seeds and the gardener’s objectives. During this period, there is a lot of room for growth. 

At the beginning of the phase, growers often move the plants to larger pots to allow their root systems to grow. The main stem then rises, increasing the distance between the nodes.

Difference Between Indoor And Outdoor Vegetation

The vegetative stage of photoperiod cultivars stops as the light cycle reduces.

  • For outdoor cultivation, such a thing happens when the summer changes to the autumn.
  • For indoor cultivation, the vegetative period ends when growers adjust the lighting. Cannabis plants now receive 12-hour light a day while moving to the new stage. 

Auto-flowering cultivars, on the other hand, begin blooming according to their age rather than the light cycle.

Significance Of The Vegetative Stage

sign of the vegetative stage
Vegetation helps prepare for the next stage

The vegetative part plays a vital role in a marijuana plant life cycle. Farmers must give their plants the absolute best environmental conditions for them to develop as healthy and large as possible. 

The size of your crop determines its yield. The larger the plant, the more nodes it develops, and the more blooms it can create. However, size is not the only consideration.

Some gardeners like to keep the cannabis plants small while still getting high yields, which they may obtain by shaping them. The strategies work best during the vegetative stage, before the first blooms form.

During the vegetative phase, several vital physiological processes are happening. Fan leaves try to transfer CO2 and light into energy. The cannabis plant’s root system is growing. It’s creating a strong anchor to avoid it from tipping over. 

The roots are also responsible for receiving essential water and nutrients. Farmers must assure that plants receive the proper quantity of light at this phase to meet their needs.

It’s also important to be aware of pathogens and pests. Growers should do all possible to avoid these dangers from harming or even destroying their cannabis crop. 

Finally, the vegetative phase prepares the cannabis plant for blooming. During this stage, the healthier the crop is, the more equipped it can be for flowering and a plentiful harvest.

How Long Does The Vegetative Stage Last In A Cannabis Plant?

Based on the particular plant size, most gardeners let their indoor cannabis plants vegetate between 4 and 8 weeks. The plants can begin flowering as early as the fourth week of the stage. As a result, those plants may be smaller than the others.

Allowing the plants to spend more time in the vegetative phase will result in larger plants. Your crop can be more likely to create better harvests.

Growers also keep some plants in the vegetative phase for prolonged periods. Hence, they can use this time expansion to take cuttings from the cannabis and create clones from this mother plant.

How Does The Cannabis Plant Change In The Vegetative Stage?

Photoperiodism is a reaction if there is any change in the light and dark cycle. 

Cannabis is a flowering plant that blooms once per year. The time and the photoperiods can determine the flowering stage. As a result, when the process is complete, the plants will die.

Photoperiodism informs the changes in light and dark cycle
Photoperiodism informs the changes in light and dark cycle

To start the flowering phase indoors, set the lights’ schedule to a 12-12 hour period. Marijuana plants can begin displaying their gender by developing pre-flowers from seeds around the fourth or sixth week. 

Basic Growing Requirements For The Vegetative Stage

Every marijuana crop is contingent on the elements listed above. When growers achieve the ideal balance between these elements, amazing development during the vegetative period is achievable. 

Let’s have a closer look at those requirements.

Pots Size

The size of your cannabis plants depends on the size of the surroundings and the pot, the number of lights you use, and the nutrient program you apply for your crop. 

The larger room the roots have in their medium, the larger the surroundings. To put it another way, the bigger and stronger your plants are, the better.

pots size of cannabis plants
Cannabis needs a large space for the root to expand


A temperature range from 22 to 26°C is ideal for marijuana plants in the vegetative phase. As a result, temperatures lower than this range may harm or even destroy your plant. Hence, don’t expose your plants to cold conditions for an extended length of time.

Furthermore, extreme temperatures have a detrimental effect on your plant. If the temperature rises above 30°C, the plant will suffer from leaf burns, excessive heat, and other troubles.


Humidity is a percent measurement of how much moisture is available in the air. Your plant develops best in a habitat with a relative humidity of 40 to 60% during the vegetative phase.


For optimal development, marijuana needs three main or nutritional content. They are Nitrogen, Potassium, and Phosphorous. We often call them NPK for short. The NPK levels are present on all plant-food packages in the form of numbers.

The ideal cannabis nutritional proportions are a point of contention. One thing needs to be clear: manufacturers tend to exaggerate the advantages of their goods for commercial purposes.

Micronutrients are also essential, but only in trace levels. Many of them are easily accessible in potting mix. You should feed your plants these components regularly. Calcium, Sulfur, Magnesium, Manganese, Boron, and Zinc are the most common micronutrients to look for.

nutrients cannabis vegetative stage
Micronutrients are essential for the vegetative stage

Furthermore, you must avoid over-fertilizing. New farmers appear to feel compelled to feed their crops as much as possible. Excessive fertilizers can cause the marijuana plants to stress. The browning of the tops of the leaves is a definite indication of nutrient burnout.

Nutrients at 1/4 of the product’s suggested amount are suitable for small seedlings. Then. you can gradually raise the amount to half. It’s worth noting that each marijuana strain has its own set of needs and limitations. 

The manufacturer’s suggestions should only be the guideline. You can figure out what your crop actually needs if you pay enough attention to it. To prevent damaging your marijuana plants, always come down on the side of caution for fertilizers.


Light sources differ in types of weed cultivation. Indoor and outdoor growers have different missions in terms of light supplies in the vegetative phase. 

Outdoor Plants

Outside farmers have far less influence on their crops. The necessary factors seize control, which may be beneficial in some situations. Hence, you don’t need to give your plants any light.

light for outdoor cannabis plants vegetative stage
You don’t have to supply light for outdoor plants

Indoor Plants

Indoor planters often choose the grow room and grow a tent for their crops to live. These habitats have their own set of benefits and drawbacks. During the whole growth phase, indoor gardeners have virtually full control over the surroundings.

They might choose to use lights between 18 and 24 hours each day during the vegetative period. The more light your plant receives, the more photosynthesis it can perform, allowing for faster vegetative development.

In indoor plants, the vegetative time can extend as long as the planter wants. Until you alter the photoperiod, the plant can keep growing and start to blossom. How long you should vegetate the crop varies according to the ultimate size you want your plant to be.

In addition, light intensity poses a significant impact. If you cultivate the plant outside, you need to determine how much light it receives.

When you measure the intensity of light in lux, we can observe that a day with little sunshine may create around 30,000 lux. If it’s cloudy, though, these values can fall under 10,000. Areas with continuous strong sunshine may reach luminosities of up to 90,000 lux.

Sunlight changes don’t affect the marijuana plants. They already have enough nutrients absorbed through the root. Moreover, the temperature remains stable. In the vegetative period, the optimum lux rates for cannabis plants are from 35,000 to 70,000 lux.

Best Grow Light For Cannabis

There are tons of choices when it comes to light sources for your cannabis crop.

  • LED

For the novice and intermediate marijuana gardeners, LED grow lights are the ideal choice. They provide the ideal balance of power-saving and adjustability. LED lamps are plug-and-play. They don’t need any airflow because they come with built-in cooling devices.

Setting the LED light system is straightforward. Your plant can grow from germination to maturity without any need for lighting systems if you use a full-spectrum LED bulb.

LED light í the most popular choice
LED light í the most popular choice
  • HPS

HPS lights are incredibly bright and generate red or yellowish wavelengths. This light source can stimulate bud growth. As a result, many farmers employ HPS during the flowering period. Their watt is superior to that of any other interior light. 

They do, however, require a great deal of power and generate lots of heat. As a result, you’ll need to change the distance from the light to your plants.

  • Fluorescent Lights

Fluorescent lights come in a variety of sizes and shapes. They vary from large twisted bulbs to lengthy pipes. Fluorescents are an ideal option for small-scale indoor gardening since they operate cool and take little energy. 

They are, on the other hand, extremely feeble. Additionally, if you cultivate a bigger garden, you could only use them as an extra light.

  • Metal Halide

Metal halide lights generate light with the blue wavelength. This spectrum is good for the vegetative phase. Some planters utilize them right up until blooming and harvesting. 

However, this light is typically not a good idea. Using it will offer your crop a much-needed push throughout the vegetative growth.

pH Levels

You should maintain a pH level of 6 to 7 in soil mixtures for healthy plant development. Most nutrients appear to be absorbed by cannabis plants at this pH level.



In both hydro and soil grows, marijuana plants need water to receive the nutrients. Water travels up from the roots of the plant to its leaves during perspiration, carrying nutrients to other parts. 

However, giving your plant too much water appears to be bad. Overwatering leads to some problems, such as limiting the oxygen content to the root. As a result, root rot will form. 

To address the issue, you need to pay attention to the top layer of the soil, especially the upper layer of three centimeters. Only give the plant more water once the layer has dried up. If not, the soil can carry that much water. 


Don’t miss the airflow part if you’re cultivating indoors. Airflow is crucial for the maintenance of vegetable plants. 

Output and input fans can keep the fresh air in the grow room. They supply your plants with CO2 and remove the extra oxygen. Mold will be less able to form if there is sufficient airflow. 

It would be best to construct a polytunnel in the wind direction or add ventilation to keep the air blowing.

Techniques To Improve Yields During The Vegetative Time

Aside from the factors above, there are numerous additional critical variables involved throughout the vegetative time.



To avoid male plants from fertilizing the grow room, marijuana plants must have sex. Growers have to detect and eliminate males as quickly as possible if they want to yield resinous blossoms. 

They’ll begin to create seeds. They also stop producing resin after the pollen has fertilized a female bloom.

Your plants should have sex in the first four weeks of the vegetative stage. Pre-flowers may appear on both female and male plants. Pre-flowers produced by males are circular. Female pre-flowers, on the other hand, have a teardrop appearance.

Gardeners can utilize a magnifying item to check the nodes. If you detect a male, you should remove them from the growing area.

Plant Training Methods

Cannabis plant training techniques
Cannabis plant training techniques

When you employ a training approach on your cannabis plants, you’re changing the chemical content. Cannabis develops a center bud (or cola) that rises high towards the light as it matures normally. 

Although the cola has the potential to grow very tall, it often creates a poor yield. It also decreases your crop’s quality.

Auxin, a marijuana hormone, is primarily vital for production. You can find it at the tops of your cannabis plants. Hence, the plant’s main objective is to climb upwards through the central stem. 

When you employ training methods like the ones we’ve described, you may limit vertical development while encouraging more even expansion. As a result, there are more flowers and better productivity.

There are Cannabis Plant Training methods that you can try!


The vegetative stage in cannabis plants prepares the foundation for the flowering period. If growers provide perfect conditions, the crop can flourish. 

We have shared with you some tips to take care of your cannabis plants during the said stage. Hopefully, you will find this article helpful.

If you need any further information, please feel free to ask.

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