The cannabis grow stages, in indoor and outdoor growing, it is that stage of the life cycle where the explosive growth of the seeds or planted cuttings takes place. It is from this stage that the development, flowering and final yield of a plant depends.

The most expert and scrupulous growers are well aware that making the slightest mistake during this stage of the life cycle can compromise not only the harvest but also the survival of the plant itself.

Help summary :

In this article we will try to answer these and other questions. And now, let's find out everything there is to know about cannabis grow stages .

Read also : “ Cannabis flowering: how to deal with it without making mistakes ”.

What is the vegetative stage and why is it important

Some consider the vegetative stage as the one that goes from seed germination to flowering. To be more precise, however, the growth of a cannabis plant can be divided into 5 stages:

  1. Germination : corresponds to the birth of the sprout from the planted seed. Lasts approximately 1 week;
  2. Seedling : the seedling begins to develop the first leaves with serrated tips typical of hemp. It lasts about 15 days;
  3. Vegetative stage : the major stage of development of the plant;
  4. Flowering : the plant is covered in shoots which will soon open, leaving space for the flowers;
  5. Maturation : flowering is complete and is followed by the harvest, where man intervenes.

The vegetative stage, therefore, is that period in which you can witness massive growth of the plant. The vegetal mass develops, the stem begins to grow in height and branch out into ever thicker branches, the fan-shaped leaves begin to multiply and become larger, to absorb more light necessary for chlorophyll photosynthesis, and the sexual characteristics of the plant.

Like the other stages of growth, the vegetative phase is also a crucial moment . In this stage the plants are preparing for optimal flowering. Negligence or errors during cultivation can affect the subsequent development of the plant. 

This is why, as you will also be able to read later, it is very important to pay attention to the aspects involved in the growth of a maria plant and which concern light, temperature, humidity, irrigation, nutrition.

But before we dwell on how to manage the needs of your plants and make them grow at their best, let's try to understand more about the vegetative phase of cannabis.

How long does the vegetative stages of a weed plants last?

We have seen that the vegetative stage of weed plant begins when the first small leaves appear on the seedling. But how long does this stage last? The correct answer is: “it depends” .

Assuming that your plant has all the optimal conditions to grow healthy and strong in height and size, the vegetative phase of cannabis can last from 2/5 weeks indoors and up to 16/17 weeks  if grown outdoors.

The times we have told you are in any case indicative because they depend 

  1. From the genetic heritage of the species ;
  2. From the grower's goal .

Depending on the desired size of the plant grown indoors, each grower can let their plants vegetate for more or less time. If your goal is to grow larger plants and bigger yields, the ideal is to leave them in the vegetative stage for as long as possible, both indoors and out. 

On the contrary, to limit the height, it is enough to plant the seeds outdoors in the late season, closer to autumn. By letting them vegetate indefinitely indoors, without forcing flowering, however, you will be able to produce cuttings and clones from the "mother plant".

Regarding the genetic heritage, the slowest growing species are the photoperiodic ones. The vegetative phase of feminized species depends on light/dark cycles, especially if grown indoors. In this case they will need at least 18-24 hours of light . The more they are exposed to light, the faster their growth will be, even 3-5 weeks.

For photoperiod plants, the vegetative phase ends when the hours of light decrease. Outdoors this happens when you transition from late summer to fall, while in indoor grow spaces, it happens when the artificial light cycle is shortened to 12 hours light and 12 hours dark.

The fastest of all, however, are those that develop from autoflowering seeds. But what is the duration of the vegetative phase of autoflowering species ? Find out by reading the next paragraph.

Cannabis growth stages of autoflowering plants: what is the duration

When does the cannabis growth stages start? Approximately from the fourth week from the moment in which the seed was placed in the substrate, germination and the seedling appeared.

Thanks to their genetic lineage Cannabis ruderalis , autoflowering plants vegetate rapidly. If you want to grow them outdoors, for example, you should start planting them in the two months when the hours of sunshine are the most.

The vegetative phase of indoor autoflowering plants , on the other hand, lasts approximately 2/4 weeks , flowering begins between the fourth and fifth week of their life cycle. Some species may be slower, others more precocious. 

In an indoor cultivation the plants do not depend on seasonal changes, therefore their entire vegetative cycle can be easily controlled by the grower by also subjecting them to cycles of 18-20 hours of light . This is because autoflowering plants are not photoperiodic varieties and, therefore, their "vegetative clock" can be manipulated by humans as soon as they are born.

How to get a good indoor and outdoor vegetative growth

The vegetative growth of a cannabis plant is essential for both indoor and outdoor cultivation. In both cases, in fact, it is necessary that the plants are in the optimal environmental conditions in order to continue to grow healthy and luxuriant, in view of flowering.

The better the health of a species during this period, the more likely it is to witness a lush flowering. After all, it is obvious, the more a plant grows, the more buds it will be able to develop. And this, you easily understand, also means bountiful harvests.

Water, nutrients, light. They are the vital elements for every plant. However, it is necessary to keep in mind the differences between indoor and outdoor cultivation. Different environments that pose different obstacles and challenges to growers.

Indoor vegetative stage

In indoor growing, the spaces available to plants are rather limited, however with the possibility of having total control over the environmental conditions throughout their life cycle.

These two elements are also the reason why growers prefer to grow indoors above all:

  • indica variety;
  • autoflowering.

Both genetics, in fact, do not reach excessive heights and dimensions. In fact, plants with sativa characteristics tend to grow considerably and can increase flowering up to 3 times. It is possible to limit the growth of cannabis with SOG and ScrOG techniques , but these are advanced modes not suitable for beginners.

However, the advantage of growing indoors is being able to control exposure to light . Lighting is important for various metabolic processes of plants, starting from chlorophyll photosynthesis. Good indoor vegetative growth requires a light to dark ratio of at least 18/6 for photoperiod strains and 20/4 for autoflowering ones. Indoor crop control isn't just about light. As you will see, it is also necessary to know how to manage other vital parameters.

Vegetative stage outdoor

An outdoor grow means less control not only over the vegetative stage but over the entire life cycle of a cannabis plant. In the open air a plantation is exposed to the elements and one relies on the rhythms of nature, but this has both advantages and disadvantages.

In outdoor growing it will not be necessary to use artificial lighting systems, being able to count on sunlight, and also irrigation will be less expensive thanks to the rains. However, outdoors you also have to deal with pests, insects and other factors that can damage your plants .

So what to do to ensure that a marijuana seedling has luxuriant growth outdoors? It becomes essential to protect it by increasing its natural defenses. Among the measures that can be taken are:

  • Using predatory insects to eliminate harmful pests;
  • Companion plants to attract dangerous insects;
  • Foliar sprays as prevention for the formation of molds and fungi.

As for the aspect of the climate , you should know that sativa-dominant plants prefer environmental conditions with a tropical tendency. Those with predominantly indica genetics, on the other hand, thrive in hot, arid climates. Autoflowering plants, given their short life cycle, can grow well even where it is colder.

When it comes to cultivation timing, it is important to consider the maximum time intervals, i.e. how long the vegetative stage of a given variety lasts. If the photoperiod species expects a vegetative growth of 5 months, then it will be necessary to plant the seeds between April and May so as to arrive at the flowering phase in autumn (between late September and early October). If autumn begins in August, however, it will be necessary to sow in March.

The autoflowering varieties that only need 2 months to flower in autumn will have to be planted 3 months after the photoperiods, in the period in which the hours of sunshine will be greatest 

What are the important factors to consider when growing a marijuana plant

We have seen how during the vegetative stage a cannabis plant lays the foundations for flowering. In this stage the fan leaves expand to capture more light and transform it into energy. The root system expands to provide the growing stem with a solid anchorage. All these physiological processes are positively and negatively influenced by some factors:

  1. substrate;
  2. irrigation;
  3. nutrition;
  4. ventilation;
  5. temperature and relative humidity;
  6. lighting.

The future of a cannabis farm depends on each of these factors. A mistake can be decisive in the failure of the harvest, which is why knowing them is essential for any self-respecting grower. Let's analyze them in detail one by one.

Cultivation substrate

The substrate is where the roots are born and develop. You can choose different types of substrates to grow plants. However, the choice will also influence the duration of the vegetative phase. 

Using the soil , the growth period may be slightly longer although it is already naturally composed of all the nutrients that the plant needs, so it is ideal for beginner growers;

Coconut fiber is a very aerated substrate , therefore the duration is shortened because good oxygenation is provided to the roots. The drawback is that it does not contain nutrients that must be administered, thus requiring even more attention in irrigation and in the control of pH, EC, temperature, etc… 

A hydroponic cultivation system allows you to significantly shorten the vegetation time, but it is a complex and laborious system to manage that only expert growers can use.

Lighting

Photoperiod plants grown indoors prefer cycles of 18 hours of light and 6 hours of darkness during the vegetative phase . By using HPS lamps and timer-controlled LED lights, it is possible to set the optimal photoperiod for a crop without causing too much stress to the plant. For autoflowering plants, on the other hand, it is necessary to provide between 18 and 20 hours of light a day in the vegetative phase.

The light-dark cycle is vital for every plant species: when they are illuminated, photosynthesis takes place, that is, light is captured and converted into chemical energy; during the hours of darkness, cellular respiration takes place, essential for the plant's metabolism, with the release of carbon dioxide. The balance between these two processes allows the correct development of the species.

Irrigation

Water is vital for a plant but cannabis needs proportionally follow its growth. Too much water can be harmful, which is why it is only necessary to water when the soil is completely dry and up to 3cm from the surface.

 The pH value of the water is also very important , optimal if between 6-7, for soil crops. The electrical conductivity (EC), on the other hand, should be around 0.4-1.2 milliSiemens. For hydroponic and coco systems, a pH of 5.5-6.5 and an EC between 1.4 and 1.6 work well.

Nutrients

Nitrogen is essential for a marijuana plant during vegetative growth . In this stage, in fact, the ratio between the NPK nutrients (nitrogen, phosphorus, potassium) should be 2:1:1 . Even if you are not an expert grower, it is easy to notice the deficiencies of a plant: if the leaves are of a beautiful green color and do not fall, it means that the nitrogen level is adequate. Instead, they would turn yellow.

Temperature and humidity

Vegetative state crops prefer temperatures ranging from 20 to 30°C during the hours of light , and 17-21°C when they are in the dark . As far as humidity is concerned, surprisingly in this phase the plants also tolerate values ​​of 60%, which are very high compared to other phases.

Ventilation

Air circulation is a very important aspect in the vegetative phase, both indoors and outdoors. Ventilation allows plants to breathe in oxygen and let out carbon dioxide. If you grow indoors, it will therefore be advisable to guarantee air recirculation with a good ventilation and exhaust air intake system.

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