Autoflowering plants are a type of cannabis that transitions from the vegetative stage to the flowering stage based on their age, typically beginning to flower around two to four weeks after germination, rather than relying on a change in the light cycle like traditional photoperiod varieties. This automatic characteristic originates from the genetics of Cannabis ruderalis, a hardy subspecies evolved to complete its life cycle quickly in regions with short summers. Autoflowers are fully capable of seed production, but this process is not spontaneous; it requires specific biological conditions or intentional intervention.
The Biological Necessity for Seed Production
Seed creation in autoflowers follows the same fundamental principles of sexual reproduction as in any other cannabis variety. Most commercially grown autoflowers are female plants, which produce resinous flowers containing only female reproductive organs (pistils). These female flowers will only develop seeds after successful pollination by male pollen.
In the absence of pollen, the female plant focuses its energy on developing seedless flowers, known as sinsemilla. A seed is the product of fertilization, requiring male genetic material to combine with the female ovule. Therefore, for an autoflower to produce seeds, a source of viable male pollen must be introduced to the female flower sites.
Intentional Breeding and Pollination Methods
Breeders must engage in a controlled process to facilitate fertilization and create autoflowering seeds. One method uses a true male autoflowering plant to pollinate a selected female. A more common technique, especially for producing feminized seeds, is to chemically induce a female plant to produce male pollen.
This is achieved by applying a solution like Silver Thiosulfate (STS) or colloidal silver to a select female plant, which then acts as the pollen donor. The silver ions interfere with the plant’s ethylene production, causing the treated areas to develop male pollen sacs instead of female flowers. Colloidal silver is often sprayed daily on the target flower sites, starting just before or at the onset of flowering.
Once the chemically induced male sacs mature, they produce genetically female pollen. This pollen is collected and carefully applied to a separate, untreated female autoflower plant. After successful pollination, the female plant diverts energy from flower production to seed maturation, which requires several weeks until the seeds are fully formed, turning dark brown and hard.
Understanding Accidental Seed Development
Seeds can sometimes appear unexpectedly in a harvest due to accidental pollination. This unwanted seeding is frequently caused by hermaphroditism, where a female plant spontaneously develops male reproductive structures. Hermaphroditism is a survival mechanism triggered by severe environmental stress such as prolonged light leaks, excessive heat, or nutrient imbalances.
In this stressed state, the female plant produces pollen sacs, sometimes called “nanners,” which can self-pollinate the surrounding female flowers. The resulting “selfed” seeds carry the same genetic predisposition to turn hermaphroditic under stress. Accidental seeding can also occur if airborne pollen from a nearby male or hermaphrodite plant enters the growing area and fertilizes the female flowers.
Preventing accidental seeding is important because the energy used to create seeds is diverted away from cannabinoid and flower production, resulting in a lower final yield and less potent flowers. The presence of seeds indicates a compromise in the environment or genetics that the grower must address to maximize future harvests.
Harvesting, Viability, and Storage
Once seeds have developed within the calyxes, proper harvesting and storage are necessary to maintain viability. A mature, viable seed is typically dark brown or mottled and possesses a hard outer shell; pale white or green seeds are immature and unlikely to germinate. Seeds should be allowed to fully mature on the plant, a process that takes four to six weeks following pollination.
After harvesting, the seeds must be separated from plant debris and allowed to dry thoroughly in a cool, dark environment. For long-term viability, store seeds in a dry, dark, and cool location, such as a refrigerator. Storing them in an airtight container with a desiccant pack, like silica gel, helps maintain low humidity. This is crucial for preserving the seed’s genetic integrity and ensuring a high germination rate.