Germination is the first step in the life cycle of a cannabis plant. It begins when the seed absorbs moisture and starts to germinate. During this process, the hard seed coat breaks open and the first root, also known as the radicle, begins to grow. This process usually takes between 3 and 10 days. Germination is crucial as it lays the foundation for a healthy plant.

Methods for germinating cannabis seeds

There are various methods to successfully germinate cannabis seeds. Here are some of the most popular:

Moist paper towel

Steps:
1. Place the seeds between two damp paper towels.
2. Place the paper towels on a plate and cover them with another plate to retain moisture.
3. Make sure the temperature remains constant between 20-25°C.
4. Check the seeds daily and keep the paper towels moist.
Advantages: Easy and inexpensive, high success rate.

Direct planting in the growing medium

Steps:
1. Plant the seeds directly into the growing medium (e.g. soil or coconut fiber) about 1-2 cm deep.
2. Keep the medium moist, but not wet.
3. Make sure that the temperature remains constant between 20-25°C.
Advantages: Less stress for the roots as no transplanting is required.

Germination in a glass of water

Steps:
1. Place the seeds in a glass of lukewarm water.
2. Leave the seeds in the water for 24-48 hours until they swell and the first roots appear.
3. Carefully plant the germinated seeds in the growing medium.
Advantages: Easy monitoring of the germination process, promotes rapid germination.

Optimal conditions for germination

To ensure successful germination, certain conditions must be met:

Temperature

Optimal: 20-25°C
Tip: Use a heating mat or place the seeds in a warm room to ensure constant temperatures.

Humidity

Optimal: Humid, but not wet environment
Tip: Cover the seeds or growing medium to retain moisture and check the moisture content regularly.

Darkness

Optimal: Dark place
Tip: Germinate the seeds in a dark cupboard or cover them with a cloth to exclude light.

Fresh seeds

Optimal: Use fresh seeds to maximize the germination rate.
Tip: Store seeds in a cool, dry place to preserve their freshness.

By observing these conditions and using the correct method, you can ensure that your cannabis seeds germinate successfully and produce healthy seedlings.

Cannabis growth phase: duration, light, temperature and humidity

Transition from germination to the vegetative phase

After germination, the vegetative growth phase of the cannabis plant begins. This transition is crucial, as the plant expands its root system and develops strong stems and leaves during this phase. The vegetative phase can last from several weeks to months, depending on the strain and cultivation goal. Good care during this phase lays the foundation for successful flowering.

Important factors in the vegetative phase

Light in the growth phase

Light is one of the most important factors for the growth of cannabis plants in the vegetative phase.

Light duration: Cannabis ideally requires 18 hours of light and 6 hours of darkness per day during this phase.
Light type: LED and HPS lamps are widely used. LEDs are more energy efficient and produce less heat, while HPS lamps often provide a higher light intensity.
Light intensity: A high light intensity promotes vigorous plant growth. Make sure the light source is close enough to the plants to provide enough light, but not so close that it burns the plants.

Nutrients and cannabis fertilizer

During the vegetative phase, cannabis plants need a balanced supply of nutrients.

Important nutrients: Nitrogen (N) is the most important nutrient in this phase as it promotes leaf growth. Phosphorus (P) and potassium (K) are also necessary, but in smaller quantities.
Fertilizers: Use special fertilizers for the vegetative phase that are rich in nitrogen. Be sure to follow the manufacturer's instructions to avoid over-fertilization.

Water requirements in the vegetative phase

An adequate water balance is crucial for growth.

Watering: Keep the soil evenly moist, but avoid waterlogging. A good drainage system is important to prevent root rot.
pH value: The pH value of the water should be between 6.0 and 7.0. An incorrect pH value can impair the plant's nutrient uptake.

Temperature and humidity

The right temperature and humidity are essential for healthy plant growth.

Temperature: Keep the temperature between 20-28°C during the day and not below 18°C at night. Temperatures that are too high can inhibit growth, while temperatures that are too low slow growth.
Humidity: In the vegetative phase, the humidity should be between 40-70%. Humidity that is too low can impair plant growth, while humidity that is too high increases the risk of mold growth.
Air circulation: Good air circulation is important to prevent mold growth and strengthen the plants. Use fans to keep the air moving in your grow room.

By paying attention to these factors, you can ensure that your cannabis plants grow healthy and vigorous in the vegetative phase, which lays the foundation for successful flowering.

Pruning and training techniques in the cannabis growth phase

Why pruning is important

Pruning is an essential part of cannabis cultivation that helps to optimize plant health and yield. Pruning removes unwanted or weak parts of the plant, which improves the flow of energy to the remaining, more productive parts. This leads to stronger plants, better light penetration and increased yield. Pruning also helps to control growth and improve plant structure.

Techniques for pruning

There are various techniques that can be used when pruning cannabis plants, each with their own benefits. Here are the three most common methods:

Low Stress Training (LST)

Low Stress Training (LST) is a technique that involves carefully bending and fixing the branches of the plant to encourage more uniform and bushy growth.

Benefits: Increases the number of flowering points, improves light distribution, minimizes the risk of plant stress.
Implementation:
1. Select young, flexible branches.
2. Carefully bend the branches downwards and secure them with soft wires or plant ties.
3. Repeat the process regularly to control growth and achieve an even plant density.

Screen of Green (SCROG)

Screen of Green (SCROG) is a technique in which a net is stretched over the plants through which the branches grow. This results in an even, flat plant structure.

Advantages: Maximizes yield per area, promotes even light distribution, makes maintenance and harvesting easier.
Implementation:
1. Stretch a net at the height of the plant tips.
2. Guide the branches through the net and distribute them evenly.
3. Cut off all unnecessary shoots and leaves below the net to concentrate the energy on the upper inflorescences.

Topping and fimming

Topping and fimming are techniques where the top of the plant is removed to direct growth into several main branches.

Topping: The top tip of the plant is completely removed.
- Advantages: Promotes the growth of two new main branches, improves light penetration.
- Procedure: Cut off the top tip of the plant with sterile scissors or a knife.
Fimming: A modified form of topping in which only about 75% of the tip is removed.
- Advantages: Results in several new shoots at the top, less stressful for the plant.
- Implementation: Cut off about 75% of the top tip, leaving some leaves and shoots.

Light in the cannabis growth phase: How long and what lighting?

Importance of light in the growth phase

Light is one of the most important resources for the growth of cannabis plants. During the growth phase, light is essential for photosynthesis, the process by which plants convert light energy into chemical energy in order to grow and develop. Sufficient and correct light promotes strong root growth, robust stems and dense foliage, which lays the foundation for a successful flowering phase.

Optimal light cycles

The light cycle in the growth phase is crucial for the healthy growth of cannabis plants.

Light duration: In the vegetative phase, cannabis plants ideally require 18 hours of light and 6 hours of darkness per day. This cycle simulates the long summer days under which cannabis grows in nature.
Light intensity: Cannabis plants need intense light to grow vigorously. Make sure the light source is close enough to the plants to provide enough light, but not so close that it burns the plants.

Types of lighting

There are different types of lighting that can be used for growing cannabis plants in the growth phase. Each has its own advantages and disadvantages.

LED lighting

Advantages:
- Energy efficient and long-lasting
- Low heat generation, minimizing the risk of heat damage
- Adjustable spectra that can be adapted to the needs of the plants
Disadvantages:
- Higher acquisition costs compared to other light sources

HPS lighting (high pressure sodium vapor lamps)

Advantages:
- High light intensity, ideal for plant growth
- Widely used and proven in cannabis cultivation
Disadvantages:
- Generates a lot of heat, which can lead to heat stress in the plants
- Higher energy consumption compared to LED lamps

Fluorescent tubes (CFL)

Advantages:
- Inexpensive and widely used
- Good light distribution, ideal for germination and early growth phase
Disadvantages:
- Lower light intensity compared to LED and HPS
- Shorter service life and higher energy consumption

Metal halide (MH) lamps

Advantages:
- High light intensity with a spectrum suitable for the vegetative phase
- Promotes vigorous and healthy growth
Disadvantages:
- Generates a lot of heat
- Higher energy consumption and shorter service life than LED lamps

Cannabis growth phase: How long does it last?

Duration of the growth phase

The duration of the growth phase for cannabis plants can vary depending on the strain and cultivation goal. As a rule, the vegetative phase lasts between 3 and 16 weeks. This phase begins after germination, when the seedling grows into a young plant, and ends when the plant enters the flowering phase.

Short vegetative phase (3-5 weeks): Often used for indoor growing and autoflowering varieties to achieve a faster harvest.
Medium vegetative phase (6-10 weeks): Often used in normal indoor and outdoor cultivation to ensure balanced growth.
Long vegetative phase (11-16 weeks): Mostly used in outdoor cultivation or special breeding projects to achieve maximum size and yield.

Factors influencing the duration

Several factors can influence the duration of the growth phase. Here are the most important ones:

Genetics of the plant

Varietal differences: Indica strains tend to have a shorter vegetative phase than sativa strains. Autoflowering strains automatically switch to the flowering phase regardless of the amount of light, which shortens the growth phase.
Hybrids: Mixtures of indica and sativa can have different growth phases, depending on the dominance of the respective genetics.

Light cycle

Light duration: The amount of light directly influences growth. An 18/6 light cycle (18 hours of light, 6 hours of darkness) promotes rapid growth. A longer light cycle can prolong the vegetative phase, while a shorter light cycle allows the plant to enter the flowering phase more quickly.
Light quality: High-quality lighting promotes healthy and rapid plant growth. LED lamps with an adjustable spectrum can optimize the growth process.

Nutrients and watering

Nutrient supply: A balanced nutrient supply with a focus on nitrogen promotes leaf growth. An undersupply can slow down growth and prolong the growth phase.
Irrigation: Consistent irrigation is crucial. Over- or under-watering can impair growth and prolong the phase.

Cultivation method

Indoor vs. outdoor: Indoor cultivation allows better control over growing conditions and can shorten the growing phase. Outdoor cultivation depends on natural conditions and can therefore vary.
Hydroponics vs. soil: Hydroponic systems usually promote faster growth through optimal nutrient supply, which can shorten the growth phase.

Environmental conditions

Temperature and humidity: Optimal temperatures (20-28°C) and humidity (40-70%) promote healthy growth. Deviations can slow down growth.
Air circulation: Good air circulation prevents mold and diseases that could impair growth.

Preparation for the flowering phase

Transition from the growth to the flowering phase

The transition from the growth phase to the flowering phase is a critical point in the life cycle of the cannabis plant. This transition is initiated by changes in light cycles and environmental conditions. While in the vegetative phase the plant is mainly focused on the growth of leaves and stems, in the flowering phase the energy is concentrated on the production of flowers (buds).

Adaptation of the light cycles

Adjusting the light cycles is the key to initiating the flowering phase. Here are the steps you should follow:

Change the light cycle: reduce the light hours from 18 hours of light and 6 hours of darkness to 12 hours of light and 12 hours of darkness. This change simulates the natural conditions that occur in the fall and signals to the plant that it's time to flower.
Light intensity: Make sure that the light source is still sufficiently intense to promote flower growth. High-quality LED lamps or HPS lamps are ideal for this phase.
Darkness: Make sure that the dark phase is completely dark. Even the smallest light leaks can disrupt the flowering process and lead to stress in the plants.

Preparing the plants for flowering

In addition to adjusting the light cycles, there are other important measures to optimally prepare the plants for the flowering phase:

Change of nutrients

Phosphorus and potassium: In the flowering phase, cannabis plants need more phosphorus and potassium to support flower formation. Therefore, switch to a flowering fertilizer that is rich in these nutrients.
Reduce nitrogen: Reduce the amount of nitrogen in the fertilizer, as too much nitrogen can inhibit flower growth and lead to excessive leaf growth.

Pruning and training

Defoliation: Remove some of the lower leaves and branches to concentrate the plant's energy on the upper buds and improve air circulation.
Low Stress Training (LST): If not already done, light training techniques such as bending the branches can be continued to ensure even light distribution.

Environmental conditions

Temperature: Keep the temperature between 20-26°C during the day and not below 18°C at night. Excessively high temperatures can impair flower growth.
Humidity: Reduce the humidity to around 40-50% to minimize the risk of mould forming on the flowers.
Air circulation: Good air circulation is crucial to prevent mold and disease. Use fans to keep the air moving.

Monitoring and care

Regular inspections: Check your plants regularly for signs of disease or pests. Early detection and treatment can prevent crop losses.
Watering: Keep the soil evenly moist, but avoid waterlogging. The plants may need a little more water during the flowering phase to support increased growth.

Common mistakes in the cannabis growth phase: watering, fertilizer and more

Overwatering and underwatering

A common problem when growing cannabis plants is incorrect watering. Both overwatering and underwatering can severely affect the growth and health of plants.

Overwatering:
- Symptoms: Yellow leaves, limp plants, root rot.
- Cause: Too frequent watering or poor drainage.
- Solution: Reduce the amount of water and ensure good drainage. Allow the top layer of soil to dry slightly before the next watering.
Underwatering:
- Symptoms: Wilted leaves, slow growth, dry soil.
- Cause: Too infrequent watering or insufficient amount of water.
- Solution: Water regularly and make sure the soil is evenly moist but not wet. Use mulch to retain moisture.

Incorrect nutrient supply

Proper nutrient supply is crucial for the healthy growth of cannabis plants. Incorrect nutrient supply can lead to deficiency symptoms or over-fertilization.

Nutrient deficiency:
- Symptoms: yellowing leaves (nitrogen deficiency), red-purple leaf stems (phosphorus deficiency), yellow leaf tips (potassium or magnesium deficiency).
- Cause: Insufficient fertilization or incorrect pH value that hinders nutrient uptake.
- Solution: Use a balanced fertilizer and make sure the soil pH is correct (6.0-7.0).
Overfertilization:
- Symptoms: Dark green, burnt leaf tips, salt deposits on the soil.
- Cause: Too frequent or too heavy application of fertilizer.
- Solution: Rinse the soil with clear water to remove excess nutrients and reduce the amount of fertilizer.

Temperature and humidity problems

The right temperature and humidity conditions are crucial for the well-being of cannabis plants. Deviations can slow growth or promote disease.

Temperature problems:
- Temperatures that are too high:
  - Symptoms: burnt leaves, slow growth.
  - Cause: Insufficient ventilation or light source placed too close.
  - Solution: Lower the temperature by improving ventilation or increasing the distance to the light source.
- Too low temperatures:
  - Symptoms: slow growth, dark green or purple leaves.
  - Cause: Growing room too cool or temperature fluctuations at night.
  - Solution: Increase the temperature by using additional heat sources or insulating the growing room.
Humidity problems:
- Humidity too high:
  - Symptoms: mold formation, slow growth.
  - Cause: Insufficient air circulation or excessive humidity in the growing room.
  - Solution: Reduce humidity by improving ventilation and using a dehumidifier. Keep the humidity in the vegetative phase at around 40-70%.
- Humidity too low:
  - Symptoms: Wilted leaves, slow growth.
  - Cause: Dry air or too much ventilation.
  - Solution: Increase the humidity by using humidifiers or water trays in the growing room.

Conclusion

The growth phase of cannabis plants is one of the most important phases in the plant's life cycle and lays the foundation for successful flowering and harvesting. With the right care and attention during this phase, growers can ensure that their plants grow healthy and strong.

Key findings:

Germination and seedling stage: Germination is the first step and requires careful conditions to ensure that the seeds sprout successfully and grow into healthy seedlings.
Vegetative phase: In this phase, the plants develop their structure and strength. Optimal light cycles, nutrients and environmental conditions are crucial for healthy growth.
Pruning and training: Techniques such as LST, SCROG, topping and fimming help to control growth and maximize yields.
Light in the growth phase: Adequate and high quality lighting is crucial to promote growth and prepare plants for the flowering phase.
Preparing for flowering: Adjusting light cycles, nutrient changes and optimal environmental conditions are necessary to ensure a smooth transition to the flowering phase.
Avoiding common mistakes: Proper watering, adequate nutrient supply and controlled temperature and humidity conditions are essential to avoid problems and promote growth.

By carefully monitoring and adjusting these factors, you can get the best out of your cannabis plants. Every step in the growing phase contributes to the health and productivity of the plants, ultimately leading to a successful and abundant harvest.

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Fachautor und Biochemier Niklas Bergmann

Niklas Bergmann, Fachautor

Freut euch auf die Insights von unserem Biochemiker Niklas Bergmann! Mit seinem tiefen Verständnis für alles, was mit Hanf zu tun hat, liefert er euch die neuesten und coolsten Infos direkt in euer Feed. Schnörkellos und klar verpackt er das komplexe Thema Cannabinoide und macht es für euch easy zugänglich. Mit Niklas an der Spitze unseres Wissens-Teams seid ihr immer top informiert.