The presence of seeds in harvested cannabis flower indicates that the female plant was fertilized during its flowering cycle. This condition is generally undesirable in commercial cultivation, standing in contrast to the industry standard known as sinsemilla, a Spanish term meaning “without seeds.” When a consumer finds seeds, it is a direct sign of a cultivation issue that interrupted the plant’s primary goal of producing cannabinoid-rich flower. The goal of modern cannabis growing is to prevent this seed formation to maximize the quality and concentration of beneficial compounds.
The Biological Reason Seeds Form
Seed development in a female cannabis plant can occur through two distinct biological pathways, both of which involve the introduction of pollen.
Pollination by Male Plants
The most straightforward cause is pollination by a separate male plant, which must be strictly isolated from the female plants. Cannabis is naturally dioecious, meaning male and female reproductive organs typically grow on separate plants. The male plant produces pollen sacs that release genetic material to fertilize the female’s flowers. If a male plant is not removed before it matures, its pollen can travel a significant distance, leading to widespread fertilization.
Hermaphroditism
The second common reason for seed formation is hermaphroditism, where a genetically female plant spontaneously develops male reproductive structures. This survival mechanism is often triggered by severe environmental stressors, such as light leaks, extreme temperature fluctuations, or nutrient deficiencies. Under this stress, the female plant develops small pollen-producing stamen, sometimes called “bananas,” to self-pollinate and ensure the species’ survival. The resulting seeds from a self-pollinating hermaphrodite will also carry a strong genetic predisposition toward developing hermaphroditic traits.
How Seeds Affect Cannabinoid Potency
When a female cannabis plant is pollinated, a significant biological shift occurs as the plant’s reproductive energy is immediately redirected toward seed production. Instead of continuing to focus on synthesizing resinous trichomes, which contain the desirable cannabinoids and terpenes, the plant begins to channel its resources into developing and maturing the seeds. This change in resource allocation is a direct trade-off between reproduction and chemical concentration.
The primary compounds like tetrahydrocannabinol (THC) and cannabidiol (CBD) are produced in the trichomes, and the diversion of energy drastically reduces their final concentration. Studies have demonstrated that fertilization can substantially decrease the total cannabinoid content in the final product. For instance, one trial observed a reduction of up to 75% in the total cannabinoid content in a high-THC variety following fertilization. This biological shift means that the resulting seeded flower will have a noticeably lower concentration of the compounds responsible for its psychoactive or therapeutic effects compared to its seedless counterpart.
Practical Drawbacks for the Consumer
The presence of seeds introduces several immediate and tangible disadvantages for the consumer beyond the reduction in potency. Seeds represent non-usable weight, meaning the consumer is paying by weight for biological material that must be discarded before use. This effectively reduces the actual amount of smokeable flower purchased, creating an economic inefficiency.
Seeds also significantly degrade the experience of consuming the flower when they are left in and combusted. When heated, the material within the seeds burns at a different rate than the surrounding plant matter, leading to an acrid, harsh smoke that is unpleasant to inhale. This combustion often produces a distinct, audible “snap, crackle, and pop” sound as the seeds are ignited. For the consumer, this necessitates the time-consuming process of manually inspecting and removing every seed before the flower can be prepared for consumption.