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Let’s Talk About Sex: Cannabis’ Dioecious Nature

Indicators of female and male cannabis plants

Male and Female Plants

A particularly exciting part of growing cannabis is observing the effects of its innate dioecious nature.

Like other dioecious species, such as hops, papayas and willow trees, individual cannabis plants feature distinctly functional male or female parts. In order to propagate through pollination and production of seed, both a female and male plant must be present. The genetics of both parent plants will be expressed in their offspring. The incredible thing is that no seeds will ever share the exact same DNA. Like snowflakes and people, no two are alike.

In cannabis flower production however, male plants are usually destroyed and pollination of female plants is done selectively and carefully.

Start From Seed

As mentioned, every plant started from seed will retain totally unique genetic potential and eventually develop male or female parts.

Most plants these days are some level of hybrid, crossed between sativa and indica. The attributes of these dominant varieties will vary and show up to different degrees as plants grow and mature.

Sativa Dominant - Longer, taller and thinner stalks, leaves and colas. Reaches maturity later in the season. Uplifting and energetic effects.

Indica Dominant - Compact, thicker and more dense stalks, leaves and colas. Reaches maturity early in the season. Sedative and psychoactive effects

However, because of years of hybridization, a single characteristic won’t necessarily coincide with other traits of the same species. The most prominent features ultimately depend on the genetics of the seed’s parents and whether it is male or female. Exposure to outdoor conditions and growing amounts of sunlight encourages a plant’s maturation and initiates the production of inherent reproductive organs.

Pollination and Seed Production

Pollination will almost assuredly happen when mature males and females share a garden space. Pollen is capable of traveling long distances through the air carried on the wind or by determined pollinators, like birds and insects. There is a risk that female plants could be fertilized and end up producing seeds rather than the desired flower, something to be aware and cautious of when growing outdoors. Pollinating a plant for seed should be done carefully in a specific process.

Superior genes for male plants are indicated by large, hollow stems, dense growth, tight flowers and a potent aroma. If kept quarantined to a remote spot in the field or in an enclosed structure, a select couple of robust males can be kept as companions and pollen producers.

Pollen is harvested when the sacs begin to open. Sacs or whole flowers are removed and placed in a bag to dry. The pollen is captured and confined to the bag.

It’s best to pollinate female plants early in their flowering stage. A healthy mother plant with desirable traits is chosen to bear seeds.

Using a paint brush, pollen is dabbed onto the flowering sites of lower branches Protruding pistils and sticky trichomes trap pollen and the fertilization process begins. Only bud sites that are pollinated will produce seed. In about 6 weeks seeds are usually ready to harvest.

Seed is a valuable commodity, necessary for the propagation of next year’s crop. Starting a large amount of homegrown seed is the best way to cultivate an outdoor crop. After the passing of several seasons, multiple generational seeds produced from the same climate and soil will be resilient to pests and well acclimated to their now native environment.

A fresh seed leads to a higher germination rate and overall viability. Starting from seed is a long process that requires great attention. Given the female yield ratio is typically around 50%, growers sow twice as many as needed.

Sexing Cannabis Plants

Seeds started as early as possible will tend to show their sex in the spring. Hardening off and moving young plants to the outdoors will hasten this process. By the time the last frost has passed and plants are ready to be transplanted into their final pot or bed, they should be ready to sex.

It is advantageous to take note of early indications to prevent spending extra time and energy growing males that will eventually be terminated. A magnifying glass can be used to study the calyxes of the developing cannabis plant. This all important part of the plant is made up by sepals, tiny leaves that protect the potential flower. The calyx is the center of the bud, the point from which the plant’s flowers are generated. It is also the place that contains the highest density of cannabinoids and produces the reproductive organs.

Female Development and Features

From the nodes and apex of the female plant, fine white hairs will begin to emerge. Females are usually shorter and grow at a more gradual rate than males. Calyxes in female plants tend not to be raised and will shoot out bright white pistils.

Some environmental factors are more favorable for increasing your chance of growing females. First of all, make sure your seedlings aren’t being stressed by exterior conditions. A stable, cooler temperature around 70 degrees combined with high humidity should boost the probability of producing female plants.

Male Development and Features

Male plants produce pollen sacs, tiny orbs that appear on either side of new growth developing from a node. They grow faster, straighter and more vigorously early on than females. In male plants the calyx will be raised on the stem where the small pollen sacs will be produced.

Males aren’t essential for flower production, but still have a crucial role in seed production. Other practical uses are producing soft fibers and juicing for consumption of healthy cannabinoids. Albeit less than females, male flowers still produce resin and THC that can be used to make hash. And their pollen is absolutely critical for preservation of preferable traits.


This anomaly occurs infrequently but is possible if plants are put under stressful conditions. When encountering unfavorable environments, cannabis plants may start to produce both male and female reproductive organs. This response is a survival technique. A plant with both parts is able to pollinate itself and ultimately reproduce seeds.

True hermaphrodites will exhibit pollen sacs and pistils on separate parts of the plant from early stages of life. On the other hand, female hermaphrodites will produce pollen at the end of the year in a desperate effort to fertilize itself and procreate. This may happen occasionally, but shouldn’t greatly affect the female plant or the rest of the crop so late in the season.

It is best to cull hermaphrodites as they appear among young plants. They will produce neither quality flower or pollen and don’t have genetics worth passing on.

Critical Sex Theory

The importance of identifying the sex of cannabis plants early in the season cannot be understated. Most growers will recognize males and immediately dispose of them. But this takes a trained eye to determine the slight variations of the developing reproductive organs. Yet with experience and maturity of the plant, the genders will become apparent. At this point, it’s time to decide the plant’s fate.

No doubt there are methods to ensure that plants are female. Cloning a mother plant and planting feminized seeds will almost always guarantee a feminine outcome. But the importance of the processes of seed starting, pollination and fertilization cannot be replaced. It is a thrilling surprise to see each unique strain express itself in unique ways, while adding to the diversity and durability of the crop. Such is the essence derived from sexual reproduction, magical and spontaneous creation, born from a true seed.



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