Cannabis plants are typically dioecious, meaning individual plants are distinctly male or female. Female cannabis plants are the source of the cannabinoid-rich flowers sought by consumers and cultivators. While these female plants are intended to remain seedless, they possess a biological capacity to produce seeds under specific circumstances. This reproductive potential is a natural survival mechanism that can be triggered by external factors or genetic predisposition. Understanding the two primary ways female plants can develop seeds is important for cultivation.
The Standard: Seedless Flowers (Sensimilla)
The baseline for high-quality cannabis production relies on the female plant remaining unpollinated throughout its flowering cycle. The term for this seedless product is sensimilla, which is Spanish for “without seeds.” This cultivation technique involves carefully monitoring and removing any male plants from the growing area to prevent fertilization.
The entire cultivation goal is to redirect the plant’s energy away from reproduction and toward resin production. When the female plant does not produce seeds, it instead channels its resources into generating trichomes. These are the tiny, glandular structures on the flowers that produce cannabinoids like THC and CBD, and aromatic terpenes. This focus on resin development is why sensimilla cannabis is prized for its significantly higher potency and more robust flavor profiles compared to seeded material.
Seed Production via External Pollination
The most straightforward way a female plant produces seeds is through external pollination by a separate male plant. Cannabis is a wind-pollinated species, meaning the male plant releases vast amounts of pollen into the air. Male plants develop small, rounded pollen sacs that burst open when mature, distributing their genetic material widely.
When this airborne pollen lands on the sticky pistils, or stigmas, of a female flower, fertilization occurs. The female plant’s energy then shifts from flower development to creating viable seeds within the calyxes. This process ensures the continuation of the species by combining the genetics of two separate plants. Cultivators must physically separate or remove male plants to avoid this outcome, as even a small amount of pollen can fertilize an entire crop.
Seed Production via Self-Pollination
Female cannabis plants can also produce seeds without a separate male plant through self-pollination, or monoecious expression. This phenomenon is often called hermaphroditism, where a female plant develops both male and female reproductive structures on the same individual. This dual-sex expression is a built-in survival mechanism that allows the plant to self-fertilize if its existence is threatened.
The causes of this self-pollination are typically environmental stress or genetic predisposition. Light cycle interruptions, such as an unexpected light leak during the dark period of flowering, can be a potent stressor. Other environmental factors like extreme temperatures, nutrient deficiencies, or physical damage can also induce the female plant to develop male flowers.
The plant develops pollen-producing structures, sometimes called “bananas” or “nanners,” which are exposed male stamens protruding from the female flower. These structures produce pollen containing only female chromosomes, which then fertilizes the surrounding female flowers on the same plant. This self-fertilization ensures the plant can produce seeds and propagate its genetics even when a male partner is unavailable.
The Impact of Seeding on Cannabis Quality
The presence of seeds within the flower material significantly compromises the overall quality of the harvest. Once a female plant is pollinated, its physiological focus immediately switches from producing cannabinoids to seed maturation. This diversion of energy halts the production of new trichomes, leading to a substantial reduction in the final concentration of THC, CBD, and terpenes.
Seeded flowers result in a harsher smoking experience because the plant material must be burned hotter to consume the seeds. The seeds themselves contain vegetable matter that contributes to a less desirable flavor and aroma. Furthermore, the usable, potent flower material is diminished, even though the added weight of the seeds inflates the total harvest mass. The result is a product with less potency and a lower market value compared to its seedless counterpart.