The Biology of the Cannabis Seed – Structure and Germination

The cannabis seed is the starting point of every cannabis plant and forms the basis for cultivation and propagation. Biologically, a cannabis seed is the fertilized seed of Cannabis sativa, containing all genetic information and the nutrient reserves required to develop a new plant.

1. Structure of the Cannabis Seed

A cannabis seed consists of several essential components that ensure its survival and its ability to germinate:

• Seed coat (Testa): The outer shell protects the sensitive embryo from physical damage, dehydration and pests. It is hard, smooth and often displays a characteristic marbled pattern.
• Embryo: Located inside the seed, the embryo is the precursor of the plant itself. It consists of:
  • Radicle: The first root that will develop into the main root system.
  • Hypocotyl: The lower part of the stem that connects the root to the young sprout.
  • Cotyledons: Two thick, rounded seed leaves that emerge first and supply the young plant with energy until photosynthesis begins.
• Endosperm: The nutrient tissue surrounding the embryo, storing starch, proteins and oils. These reserves supply the seedling until it can sustain itself through photosynthesis.

2. Germination of the Cannabis Seed

Germination begins when the seed is exposed to optimal environmental conditions. Three factors are crucial:

• Moisture: Water activates enzymes within the seed and softens the seed coat.
• Heat: Ideal temperatures range between 23°C and 25°C.
• Oxygen: Essential for cellular respiration and energy production in the developing plant.

Once the seed absorbs water, it swells and its metabolic processes activate. The radicle breaks through the shell first and forms the primary root. Soon after, the hypocotyl and the cotyledons begin to rise. Once the cotyledons reach the light, the plant initiates photosynthesis and becomes independent from the nutrients stored in the endosperm.

3. Influence of Storage and Seed Quality

The germination ability of a cannabis seed is strongly influenced by storage conditions. Excess humidity, temperature fluctuations or exposure to light can damage the delicate biological structures inside the seed and reduce germination rates. When stored correctly, cannabis seeds can remain viable for several years.

Genetics also play a major role: high-quality cannabis seeds come from stable parent plants that have been selectively bred for yield, resilience and cannabinoid profile.

4. Female vs. Male Seeds

Natural cannabis seeds randomly produce either male or female plants — a process still not fully understood and currently being researched. Learn more in the article “Increasing the Percentage of Female Plants in Regular Seeds.”

For flower production, only female plants are desired, as they produce the resin-rich buds. Therefore, many modern seed lines consist of feminized seeds, which produce almost exclusively female plants.

5. Seeds vs. Clones

Unlike clones (cuttings), which are genetically identical to the mother plant, plants grown from seeds show unique genetic variation. This can offer advantages (new, interesting traits) but also risks (instability).

In summary, the cannabis seed is a small but powerful biological unit containing life, energy and the full genetic potential of the cannabis plant. From germination to harvest, every grow begins with this remarkable natural structure.

Sex Determination in Cannabis – Genetics, Environment, and Hormonal Influence

There is strong evidence that the development of male or female cannabis plants is not purely random, but influenced by several internal and external factors. Sex determination in cannabis is complex and depends on both genetic predisposition and environmental conditions.

1. Genetic Predisposition

Each plant carries chromosomal information: Cannabis has X and Y chromosomes, similar to humans.

• Plants with XX chromosomes develop into female plants.
• Plants with XY chromosomes develop into male plants.

However, this genetic determination is not absolute, because…

2. Influence of Environmental Factors (Environmental Sex Determination)

Scientific studies and grower observations show that certain environmental conditions can influence the likelihood of a plant becoming male or female.

Key environmental factors include:

• Temperature: High temperatures tend to promote male plant development.
• Light intensity and spectrum: Stress caused by insufficient or excessive light can affect sex expression.
• Nutrient availability: Excess or deficiency of nutrients—especially nitrogen—can influence hormonal processes.
• Humidity: Very dry or overly humid environments can cause stress and influence sex development.

3. Plant Stress and Hermaphroditism

Under stress conditions (light leaks, nutrient problems, physical damage), some cannabis plants develop hermaphroditic traits: they produce both male and female flowers.

This mechanism is a survival strategy that allows the plant to self-pollinate when reproductive opportunities are limited.

4. Hormonal Regulation

The formation of male or female flowers is strongly influenced by plant hormones:

• Gibberellins promote the development of male flowers.
• Ethylen promotes the development of female flowers.

This is why hormones or chemical agents (such as colloidal silver) can be used intentionally to influence the plant’s sex—commonly used in the production of feminized seeds.

Conclusion

Sex determination in cannabis is not purely random but the result of an interplay between genetics and environmental factors. Growers can increase the likelihood of female plants by optimizing environmental conditions and avoiding stress. However, only feminized seeds offer a fully reliable outcome.