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Cannabis Seedling Plants: How To Care And Protect?

The seedling stage is quite important in growing cannabis plants that everyone needs to be aware of. Therefore, people are very interested in the care of cannabis seedlings in the seedling stage.

To have a good, high-quality cannabis harvest, you must first have good seedlings. However, many people make the mistake of taking care of cannabis at the young plant stage.

Read this article right away if you are also learning how to take care of seedlings when growing cannabis. Below is a summary of the issues to keep in mind during the seedling stage.

What Do Healthy Seedlings Look Like?

healthy seedlings
Healthy Seedlings

First, to take good care of your cannabis plant, you should know what the signs of healthy seedlings look like. From there, you can determine if your seedlings have any problems and need to be adjusted for the best growth.

Like other plants, cannabis grows from seeds, so it will initially have two round leaves or cotyledons. Then, the main leaf of the plant will grow out in the middle.

Gradually, the seedlings begin to grow, and these main leaves develop like the regular cannabis leaves you are used to seeing. At the same time, the cotyledons may age, gradually wilt and fall off.

A healthy young cannabis plant is naturally green, normally growing leaves. The leaves are healthy and free from pests or fungi.

Thus, if your seedlings grow normally and are healthy, you do not need to worry much. On the contrary, if the tree has signs of irregularity on the leaves and stem, you need to pay attention to ensure that the tree always grows well.

How to Choose the Right Genetics?

First, you need to choose the source of the best quality seeds. Especially if you are a beginner, you should select seedlings with good growth ability and easy to care for.

Those with experience should choose a familiar seedling that you have planted many times. Because some types that you already have experience with will also be easier to take care of young plants.

Budget will also be a factor for you to decide which cultivar to choose.

How To Choose The Best Growing Mediums?

cannabis medium
Cannabis Medium

You should provide your cannabis seeds with the best growing media conditions. Growing media includes all requirements of moisture, light, and medium.

You should grow young plants in an environment with suitable light and humidity. Young plants are quite sensitive, and it is best to use slightly acidic soil for this stage (soil should have a pH between 6.3 and 6.5).

In addition, you can use more perlite to help aerate the soil and add organic nutrients to the ground to help young plants grow quickly. You should mix the potting soil with the ratio of perlite about 20 – 50% because they will help drain water and prevent vegetative lock in the young plant stage.

Besides, young plants are very sensitive to nutrients, and when their pods are not yet developed, they cannot absorb nutrients. Therefore, you do not need to choose a nutrient-rich soil medium for young plants, nor should you add any nutrients to them.

At the same time, paying attention to maintaining humidity and stable light will be better for your seedlings.

What Are The Basic Requirements for Vegetative Stage?

In taking care of seedlings from the seed stage to becoming a young plant, you need to pay attention to meet the best growing conditions for the tree. Some of the development requirements of the plant during the growth phase that people need to keep in mind include:

Containers – Pots Size

cannabis containers
Cannabis containers

Containers are essential when you are growing cannabis seedlings. In particular, you need to pay attention to the size of the container to choose the right size for the growth of young plants.

Because you can transplant young plants to another container to allow them to mature and flower, when the plants are young, you can choose a smaller container first.

The small container not only saves nutrients but also helps your seedling to absorb water and nutrients best. 

In particular, when grown in a suitable container, your plants can make the best use of that space to stimulate root growth.


lights seedling stage

Usually, people will grow young plants indoors to adjust temperature and humidity easily and create the most optimal growth environment for young plants. However, growing indoors, you will have to use lights to produce light.

The young plant stage is quite sensitive and does not need to be stimulated to grow too quickly. Therefore, the amount of light the plant needs does not need to be too strong and direct. You should use lamps with suitable light, not too harsh, or too hot.

Specifically, Compact fluorescent lamps with cool blue spectrum light are a great choice. They give young plants just enough light without heating up the space, which is very suitable for this sensitive stage of plants.

You should light your seedlings continuously for 18 hours a day then take a 6-hour break in terms of lighting time. A longer exposure time with soft light is very suitable for young cannabis to grow well.


Temperature is also a factor you need to consider when growing cannabis plants at a young plant stage. Since plants are quite sensitive, you need to maintain a constant temperature at the optimum level.

You should keep the temperature no more than 80 degrees F and at night should reduce it to about 70 degrees F for young plants to grow healthy. Since indoor plants can control the temperature, check regularly and adjust to maintain this temperature.


Besides temperature, humidity also greatly affects the growth of cannabis plants.

At the young plant stage, the tree’s roots have not developed, so the ability to absorb water is not good. However, young plants are quite sensitive, so you should not let them get too dry.

During this stage, you should maintain a higher humidity than in other locations of the cannabis plant. Humidity should be maintained in the range of 70% to help the leaves absorb heat from the environment and reduce pressure on the roots.

At the same time, you should not water too much because the roots can not absorb well.


nutrients cannabis seedling-stage

Nutrients are an important factor in the care of young plants.

Normally, you won’t need to add nutrients to the plant because you already mix the nutrients into the soil as soon as you create the pot. Your young plant only needs to absorb this mixed organic nutrient.

You need to provide the right amount of nutrients to support the best growth of cannabis in the young plant stage.

That is, you should not allow young plants to lack nutrients or have excess nutrients. Because if there is a shortage, the plant will be slow to grow, and if it is too much, the plant will not absorb it all, both wasteful and increasing the risk of plants being poisoned and dying.

Some signs on young cannabis plants that indicate an excess or lack of nutrients that you should pay attention to include:

    • Young plants are dark in color (while healthy plants are lush green)
    • On the leaves, there are yellow spots, burn marks
    • Leaves curled or wilted, yellowed

Note that in the young plant stage, you should use organic nutrients. Young plants will slowly absorb these nutrients and grow healthier than using chemical nutrients.

pH Levels

ph level cannabis seedling
pH Levels

During any stage of the cannabis plant’s growth, the pH level is always an indicator that people must keep in mind. Especially at the young plant stage, the tree is very sensitive, so the pH of the environment needs to be suitable to help the plant absorb nutrients well.

Many experts believe that the best environment for young cannabis plants will be slightly acidic, and a pH between 6.3 and 6.5 is best.


At the seedling stage, control the amount of water you water the plant. At this stage, the plant’s roots are not fully developed, so the ability to absorb water is quite slow, and the amount of water absorbed is not much.

So, water is just enough to ensure the plant can absorb it well and maintain optimal humidity. You shouldn’t water too much, but you shouldn’t water too little either.

One trick is that you can water less and divide it into several waterings. This type of watering helps the roots to absorb the best and does not make the plant waterlogged. At the same time, it also helps your young plants stay in a constant state of water.

What Happens During The Seedling Stage?

Caring for seedlings is also an issue that you need to learn carefully to support the best growth. Young cannabis plants are often very fragile and have little resistance, so you need to care for them.

The seedling stage is very important in the cannabis growing process. Healthy young plants will create a good premise for later growth and flowering. Therefore, you need to pay attention to take good care of your seedlings.

Your task is to give the seedling the most optimal environment for healthy growth. It not only includes factors when preparing to plant but also depends on taking care of the tree.

Problems that may occur during the seedling stage that you need to be aware of include:



Overwatering is a condition in which plants are deprived of oxygen and usually occurs when plants become waterlogged because you over-water them. You can refer to some information about the signs of causes and how to fix Overwatering phenomenon as follows:

The Symptoms:

First, you can detect your young tree has this problem based on some symptoms of the tree. Specifically, a popular example is seedlings droop, and the substrate is wet or flooded because the plants cannot absorb water.

Because inappropriate growing container size (container is too big or container is too small), the container’s drainage is poor, or because you water is too much.

Under Watering

On the contrary, Under Watering is a problem when you water the plants too little. This problem has many similarities with Overwatering, so you are often confused and take wrong actions.

At the young plant stage, the roots need to be in contact with moist soil at all times, which means higher humidity. Therefore, if watering less, the plant will dry out very dangerously.

The Symptoms:

Some of the symptoms of young plants experiencing Under Watering are: the plants are drooping, wilting, wilting; The plant is slow to grow, the stem is soft, and the growing medium around the plant is too dry.

The cause of this phenomenon can be due to your soil being too dry, not rich in nutrients, poor water holding capacity, draining too quickly, and because you water too little.


Cannabis Damping-Off

Damping-off is a phenomenon in which your young tree is suddenly healthy in 24 hours or less. The tree lying on the edge of the barrel gradually shrinks and dies. The cause of this problem can come from the growth of some harmful fungi such as Pythium, Fusarium, or Botrytis.

Normally these fungi just lie dormant in the soil, but when the humidity is high, they will grow and affect young plants and cause plants to Damping-off.

The first sign of this phenomenon is that the seedlings begin to soften, and unfortunately, you will not be able to correct this situation. What you can do is immediately remove the containers and seedlings that are Damping-off from the garden to prevent these fungi from spreading further.

To avoid this phenomenon, first, you need to control the quality of the soil well. Make sure it doesn’t contain any of these harmful fungi.

Besides, in taking care of young plants, regularly check the temperature and humidity of the environment. Do not let the humidity get too high as it can create favorable conditions for harmful fungi to grow, causing Damping-off.

Nutrient Problems

cannabis seedling nutrient problems
Cannabis seedling nutrient problems

During the growth of young plants, you cannot help but provide nutrients to the plants. A common problem with nutrients is that you are applying too much or too little.

Normally, nutrients will be mixed with the soil, rarely added at the young plant stage. Therefore, for plants to grow well, right from soil preparation, you need to balance the right amount of nutrients for plants during the young plant stage.

If the nutrients are too little, the plant will be stunted, slow to grow, and the leaves will wilt. On the contrary, when you fertilize too much, the plant cannot absorb it, so it is very wasteful and can even lead to “nutrient burn” that darkens the tips of the leaves.

Ideally, in the seedling stage, you should use organic nutrients. Your young plants can slowly absorb the organic matter you mix in the potting soil.

This absorption process takes place slowly in a natural way to help the roots grow at their best. As a result, your young plants grow safe and healthy.

Especially when using organic nutrients, you will not need to worry about the plant being shocked or burning nutrients. Compared with chemical nutrients, organic nutrients are more soluble and active. Therefore, they are best suited for the seedling stage.

Too Much Heat

Too Much Heat for cannabis
Too Much Heat for cannabis

Excessive heat is also a common problem in the care of young cannabis plants. A common sign is that the leaves are bent at the edges. At the same time, there are many leaf spots on the leaves, the edges of the leaves are rolled up.

In addition, red stems, petioles, and lemon-yellow leaves are also warning signs that your young plant is overheating.

The cause of this problem is that the growing room temperature is too high and the environment is too dry, and not watering the plants enough.

Therefore, you should regularly check and maintain the optimal growing room temperature (from 20- to 25 degrees Celsius) to overcome this problem. At the same time, do not forget to water regularly with just the right amount for your young plants.

Pests And Bugs

The impact of pests is also an environmental issue that you need to consider when growing cannabis in the seedling stage. Growing cannabis seeds indoors with carefully selected soil also helps limit the impact of harmful pests.

However, your young plants are still at risk of being affected by insects such as spider mites, rodents, powdery mildew, harmful fungi, etc.

These pests grow very quickly, and they can affect your young plants in as little as a day. Even, the tree is healthy, if these pests invade, they will destroy your young tree.

Signs of harmful insects can gnaw leaves and worms, and holes appear. Even some pests and fungi can cause strange diseases on cannabis plants that cause the plant not to grow normally and die.

To overcome pest problems, it’s important to choose good soil. At the same time, keep the growing room environment clean, not creating conditions for pests to develop.

Seedlings Stretch

Cannabis seedlings stretch
Cannabis seedlings stretch

As is known, plants tend to lean towards the light source, and so do cannabis plants. A common problem in the seedling stage related to tree lighting is Seedlings Stretch.

A sign of this problem is that your cannabis plant is unusually tall, the stem is one-sided, and the branch is very small.

Inadequate lighting will cause your young plants to grow abnormally because they are very long and fragile.

Ideally, you should use light with a blue spectrum located about 5cm from the top of the plant. Note, the light needs to spread so that the plant does not point in one direction.

In particular, as soon as the plants have sprouted, you should not leave them in the dark all day. Because if you do so, it is very easy for young plants to find their way to light and have Seedlings Stretch problems.

Growing Seedlings Outdoors

Usually, people will choose to grow seedlings indoors rather than growing them outdoors. Because, when growing young plants outdoors, you cannot control natural factors such as light, humidity, temperature, precipitation…

Meanwhile, young cannabis plants are fragile, sensitive and they need an optimal environment to grow best. That’s also why, despite choosing to grow cannabis outdoors, most people will let them go through the seedling stage indoors.

However, that doesn’t mean you can’t grow young plants outdoors. If you decide to grow seedlings outdoors, you have two options:

You can keep your sapling outdoors during the day, but it’s a good idea to bring it indoors at night. Because, at night, the weather is often cold, the humidity is high, and many dangers hinder the growth of plants.

You can keep your cannabis outdoors both day and night if you grow it in a breeder or greenhouse or tunnel – places specifically designed to create the optimal environment. 

However, this option will be very expensive because to control temperature, humidity, and other conditions, you need to invest in a lot of modern equipment.

Besides, growing young cannabis plants outdoors is difficult and not good for the plant’s growth. You should also note that, in natural conditions, young cannabis plants should only be taken outdoors when the temperature is stable between 20-25 degrees Celsius. And there is suitable humidity.

When and How To Transplant Your Seedlings?

How To Transplant Your Seedlings

Another important issue you need to consider regarding the seedling stage when growing cannabis is when and how to transplant the seedlings. That is, when and how you move the sapling to a new container.

In fact, your sapling will not be able to grow in a container from seed stage to harvest. Because, at each step, you should increase the plants in the right sized container to ensure a supply of nutrients and moisture.

So, in growing cannabis, you need to undergo the transplant of the young plant to a new pot. More specifically, here we will help you determine when and how to perform the transplant.

When To Transplant Young Plants?

You should transplant young plants just before they grow larger than the current container size. Because it will help the plant adapt to the new growing environment and stimulate the plant to grow better. You can base on many different signs to choose when to transplant.

In terms of time, usually, you can transplant the young plant to a new pot after the seeds have germinated for 4-8 weeks. 

In addition, you can rely on the characteristics of the plant to decide when to put the young plant in a new pot.

    • Based on the number of leaves: Count the number of leaves of the young plant. If your tree has developed 4-5 sets of leaves and the foliage is spreading, it’s time for a transplant.
    • Root development: Usually, there will be a drainage hole, and you can observe the growth of the roots here. If the roots grow healthy and come out of the hole, you can proceed with the transplant. In addition, if you notice that the roots are turning darker or black, this is a sign of rooting, and you should transplant immediately.

When the tree has the above signs, you should perform a young tree transplant immediately. Because it saves recovery time and aids the rooting of the plant in the new container.

How To Transplant Saplings?

To ensure that the cannabis plant can grow well in the new container, you need to perform the transplant by following these steps:

    • First, wash your hands or wear gloves to avoid contaminating the roots of the plant. The young plant’s roots are very sensitive and fragile, so it’s best to keep the area around the roots clean.
    • Water, the plant with a little water, to reduce friction when you remove the sapling from the container. 

However, don’t over-water and let the soil get too wet because the water is fragile, making it difficult to move the container, and the roots can be damaged.

    • Put the soil in the new container, and don’t forget to make some space ready to put the sapling in.
    • Then, put the sapling in a new container and fill it with soil up to the trunk. Do not cover the soil too tightly because it will make it difficult for the roots and drainage system to work. Ideally, you should create space for roots by filling them with tight but not compacted soil.
    • In particular, you minimize the risk of your young tree being shocked by not erasing its roots when transferring to a new container. Gently move the sapling from the old container to the new medium, making sure not to damage the roots.

Note to care for young plants after transplanting: you should not leave the plants right indirect light because when the plants have not taken root, the light is too strong, it can shock them. Besides, do not forget to use a drip watering can water the plants regularly.

In addition, after transplanting, you should also regularly observe and check to detect abnormalities of young plants. It will help you take timely actions to help young plants grow best.


Young plants are often very fragile, so people need to pay special attention to taking care of them. The seedling stage is the foundation for the growth of the cannabis plant.

Therefore, to ensure the good growth of plants to help harvest quality and high output, people need to pay attention to taking good care of seedlings.

Hopefully, with the information, we provide in this article, you can better understand the seedling stage and its importance to cannabis cultivation.

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