Weed Sexing: Male and Female Marijuana Plants
Cultivating marijuana for your personal use is challenging and rewarding. Like any plant, cannabis requires proper light, temperature, nutrients, and water to thrive. If you are a medical marijuana patient in a state that allows home cultivation, you can ensure that you have a supply of high-quality marijuana by growing it yourself.
Growing cannabis is a unique project because it’s a dioecious plant, meaning it has two sexes. Your plants can be male pollinators or female seed producers. Learning how to identify male marijuana plants, female marijuana plants, and hermaphrodite cannabis plants by their reproductive organs is an essential skill for every home cultivator.
Successful growers separate male and female cannabis plants before they are mature to prevent cross-pollination. Their vigilance is rewarded with THC-rich flowers instead of just cannabis seeds.
Read on to learn more about sexing marijuana plants, the gender identification timeline, and how to optimize your harvest.
What is Cannabis Sexing?
Cannabis sexing is the simple process of identifying male and female weed plants based on their anatomy. At three to four weeks, cannabis plants begin to show their sex. Male plants produce pollen sacs, which they use to fertilize flowers. Female marijuana plants produce buds, which blossom into flowers that contain THC and trichomes.
In rare cases, cannabis plants can grow as a hermaphrodite from their seeds due to their genetic makeup or become hermaphroditic during their growth due to trauma and poor growing conditions.
These plants develop banana-shaped pre-flowers and have both sex organs once they mature. Hermaphroditic plants, also known as hermies, do not produce usable THC.
As a home cultivator/breeder, sexing plants can be initially stressful due to the similar nature of marijuana plants in their seedling and vegetative stages. Fortunately, marijuana plants have telltale signs of gender as they age.
The strain of cannabis you grow and the seeds you use will impact how quickly your plants present sexual characteristics. It’s best to check early and often for the early signs of plant gender.
Why Should You Sex Cannabis Plants?
Sexing your cannabis plants is vital for preserving your harvest. Male plants produce only trace amounts of THC. They are primarily used for breeding, turned into hemp fiber, or ground into essential oil. Male plants are usually taller than female plants, with thinner leaf dispersal.
Female plants are more valuable because they contain the THC, trichomes, and terpenes that give cannabis its ability to create physical and psychological effects in the human body.
As a home cultivator, sexing plants as early as possible helps save you time and money because pollinated female plants do not produce usable medical marijuana. A ruined harvest can set you back weeks or months.
If a female plant gets pollinated, it ceases THC production and develops seeds. Failure to spot the early signs of male plant development could ruin your entire harvest, leaving you without usable marijuana. Unpollinated female plants, called Sinsemilla, are the goal of home cultivation.
How to Sex Cannabis Plants
The only way to identify marijuana plant sex is with a visual inspection. In their initial growth stages, male and female plants look similar. As they mature, the plants develop small balls called pre-flowers.
The structures are present at the node, where the main stem meets a branch. Typically, the pre-flowers do not appear until the plant has five or six nodes.
The balls are small. Examining them with a magnifier ensures you properly sex the plant. Male pre-flowers have smooth pre-flowers that are orb-shaped. On the other hand, a small ball with two hairs growing out of it and bushier leaves are the early signs of female plant development.
Female plants are generally shorter and fuller than their male counterparts.
The white hairs on the female plant grow in a V shape, forming the sigma. Together, the ball and sigma form the pistil. As the plant matures, the sigma grows into the structure that captures male pollen.
Once the plants are sexed, you should remove the males and destroy them. If allowed to reach sexual maturity, the pollen sacs will burst and fertilize nearby female plants.
When to Sex Cannabis Plants
Male plants generally grow faster and present sexual characteristics earlier than female plants. The earliest you can spot a male plant is three to four weeks after germination.
Female pre-flowers develop as early as four to six weeks from germination. The growth conditions and strain of cannabis impact how fast the plants mature, but it’s best to begin checking once the plant has several nodes.
Identifying and removing male plants as early as possible is critical to the success of your harvest. A single male produces enough pollen to fertilize hundreds of female plants. Males release pollen between seven and ten weeks after germination. Early sexing and removal protects your female plants from pollen.
What are the early signs of a male cannabis plant?
The earliest sign of a male cannabis plant is the presence of small balls at the juncture between the stem and branches. They first appear three to four weeks after the plant germinates.
What are the early signs of a female cannabis plant?
The earliest you can spot signs of a female plant is four to six weeks after germination. They will have clusters of balls at the nodes. A sigma, two hairs that form a V, will stick out from one end of the ball.
Can you tell if a cannabis plant is male or female before flowering?
Yes. You can sex your cannabis plants about a month after they germinate based on the structure of their pre-flowers. Only female plants grow flowers.
What are the first signs of flowering?
The appearance of the pistils, the balls with the sigma, on the female plant is the earliest sign that the plant is entering its flowering stage. Between three and four days after they first appear, the pistils will expand and form clusters that will become buds.
What triggers flowering?
The flowering stage begins when the pre-flowers appear, males develop pollen sacs and females grow pistils. Changes in light exposure induce cannabis flowering. In the wild, the plant usually flowers in the late summer or fall. Home-cultivated cannabis enters the flowering stage once it receives 12 hours of light and 12 hours of darkness.
Can you tell a plant’s gender by its seed?
There is no way to tell a future plant’s gender based on its seeds. Reputable vendors sell feminized seeds, which are bred to maximize the likelihood of yielding female plants. It is possible to grow a male plant from feminized seeds.
How we reviewed this article:
Jake Peter received his journalism degree from Emerson College and has been writing content for the Sanctuary Wellness Institute since 2021. He is passionate about all things cannabis.