How to Sex Cannabis Plants Before Flowering: A Complete Guide

How to Sex Cannabis Plants Before Flowering: Complete Guide
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How to Sex Cannabis Plants: Difference Between Male vs Female Plants

If you are growing weed for personal use or for commercial purposes, you may want to know the sex of your plants before they start flowering. This is because female plants produce resinous buds that are rich in cannabinoids, while male plants produce pollen sacs that can fertilize the female buds and reduce their quality and potency.

In this blog post, we will explain the when, why, and how to sex cannabis plants and much more.

What Are the Main Differences Between Male and Female Plants?

How to Sex Cannabis Plants Before Flowering: Complete Guide

Besides producing different types of flowers, male and female cannabis plants also have some other differences that affect plant growth and appearance. Here are some of the main differences between male and female plants:

  • Males tend to grow taller and thinner than female weed plants, which tend to be shorter and bushier.
  • Males tend to have fewer leaves and branches than female plants, which tend to have more foliage and a denser structure.
  • Males tend to mature faster than female plants, which tend to take longer to reach the flowering stage.
  • Males tend to have lower levels of cannabinoids than females, which tend to have higher levels of cannabinoids.

Why is Knowing the Sex of Your Plants Important?

Cannabis sexing is important for several reasons. First of all, if you are growing cannabis for consumption, you want to avoid pollination of your female plants by male plants. Pollination will cause your female plants to produce seeds instead of buds, which will lower their cannabinoid content and make them less desirable for smoking or making extracts.

Seeds also take up space and weight that could be used for more resin production. Therefore, you should remove any male plants from your grow area as soon as you identify them, or keep them separate from your female plants if you want to use them for breeding purposes.

Secondly, sexing plants can help you optimize your growing space and resources. Male plants tend to grow taller and thinner than female plants, while female plants tend to grow shorter and bushier.

Knowing the sex of your plants can help you adjust your lighting, pruning, training, and feeding techniques accordingly. For example, you may want to give your female plants more light and nutrients to increase their bud production, by pruning or topping them to control their height and shape.

When to Sex Your Cannabis Plants?

How to Sex Cannabis Plants Before Flowering: Complete Guide

Cannabis start showing early signs of their gender when they enter the pre-flowering, which usually happens around 4-6 weeks after germination. However, some strains may show their sex earlier or later than others, depending on their genetics and environmental factors.

The pre-flowering is also influenced by the light cycle that you expose your plants to. The plants of cannabis are photoperiodic, which means that they respond to changes in the length of day and night.

In nature, cannabis start flowering when the days get shorter and the nights get longer, which signals the end of summer and the beginning of autumn. In indoor growing, you can induce flowering by switching your light cycle from 18/6 (18 hours of light and 6 hours of darkness) or 24/0 (continuous light) to 12/12.

This will trigger your plants to produce hormones that initiate the flowering process.

How to Identify Male or Female Plants?

cannabis flowering stage, sexing cannabis plant, male female flowers

The easiest way to identify the sex of your marijuana plants is to look at their pre-flowers, which are small structures that appear at the nodes (where the branches meet the stem) of the plant.

  • Male pre-flowers look like small balls or sacs that hang from a short stalk. These sacs will eventually open and release pollen into the air.
  • Female pre-flowers look like tiny white hairs or pistils that emerge from a tear-shaped calyx. These pistils will later catch the pollen and form seeds.

If you see pre-flowers on your plants, you can use a magnifying glass or a camera to get a closer look and determine their sex. You can also take a picture and zoom in on it later. If you are not sure about the sex of your plants, you can wait until they develop more pre-flowers or until they start flowering.

How To Know The Sex and Potency of Your Plants Before Pre-flowering

If you want to determine the sex and potency of your plants even earlier than the pre-flowering, you can use a chemical leaf test. This is a method that involves taking a small sample of leaf tissue from your plant and applying a chemical reagent to it. The reagent will change color depending on the presence and concentration of cannabinoids in the leaf. Cannabinoids are the active compounds in cannabis that are responsible for its effects and medical benefits.

There are different types of chemical leaf tests available on the market, such as THC Test Kits, CBD Test Kits, and Gender Test Kits. Each kit comes with instructions on how to use it and interpret the results.

Generally, you will need to cut a small piece of leaf from your plant, place it on a testing plate or strip, add a few drops of the reagent, and wait for a color change. The color will indicate the sex and potency of your plant, according to a color chart provided with the kit.

Chemical leaf tests can be useful for growers who want to select the best plants for cloning or breeding, or who want to monitor the cannabinoid levels of their plants throughout their growth cycle.

However, chemical leaf tests are not 100% accurate and reliable, as they can be affected by various factors such as plant age, strain, environment, and reagent quality. Therefore, you should always confirm the sex and potency of your plants by checking their pre-flowers or flowers when they appear.

Can You Influence the Sex of Your Plants?

The sex of your marijuana plants is determined by their genetics and their environment. Some strains are more likely to produce female plants than others, so you can choose feminized seeds or clones from reputable sources to increase your chances of getting females.

However, even feminized seeds or clones can turn into males or hermaphrodites if they are exposed to stress factors. Therefore, you should provide optimal conditions for your plants and monitor them regularly for signs of stress or sex change.

What Is a Hermaphrodite Cannabis Plant?

How to Sex Cannabis Plants Before Flowering: Complete Guide, Hermaphrodite plant

A hermaphrodite plant is a plant that has both male and female characteristics. This can happen for two reasons: either the plant is genetically predisposed to be hermaphrodite, or it is stressed by environmental factors that trigger a survival mechanism.

Some cannabis strains are more prone to hermaphroditism than others, especially if they have been bred from hermaphrodite parents. This is why it is important to get your seeds or clones from reputable sources that guarantee their quality and stability.

Environmental stress can also cause cannabis plants to become hermaphrodites. Some of the factors that can stress your plants are:

When cannabis plants are stressed, they may try to reproduce as quickly as possible before they die. This means they may develop male flowers alongside female flowers, or even within them. These male flowers can then pollinate themselves or other female plants nearby, resulting in seeds.

How to Prevent or Deal With Hermaphrodite Plants?

The best way to prevent hermaphroditism in your cannabis is to avoid stressing them as much as possible. This means you should provide them with optimal growing conditions, such as:

  • A consistent light cycle of 18/6 hours for the vegetative and 12/12 hours for the flowering stage
  • A dark and light-proof grow room or tent
  • A comfortable temperature range of 18-26°C (65-79°F) and a humidity level of 40-60%
  • A well-drained and aerated growing medium with adequate nutrients and pH
  • A regular watering schedule that keeps the soil moist but not soggy
  • A pest and disease prevention and control system
  • A gentle training and pruning technique that does not damage the plant

If you notice any signs of hermaphroditism, such as male flowers or bananas (elongated yellow sacs that contain pollen), you should act quickly to avoid pollination. You have two options: either remove the hermaphrodite plant entirely from your grow space or remove the male flowers carefully with tweezers or scissors.

If you choose to remove the male flowers, you should do it as soon as possible, before they open and release pollen. You should also check your plants daily for any new male flowers that may appear. You should also isolate the affected plant from other female plants, if possible, to prevent cross-pollination.

If you choose to remove the hermaphrodite plant, you should do it carefully, without shaking it or disturbing other plants nearby. You should also dispose of it properly, preferably by burning it or burying it deep in the ground. You should also clean your grow space and equipment thoroughly, to eliminate any traces of pollen.

How Can You Prevent Pollination of Your Female Cannabis Plants?

How to Sex Cannabis Plants Before Flowering: Complete Guide, Hermaphrodite plant

If you want to prevent pollination of your female cannabis plants, you will need to separate them from your cannabis cultivation as soon as you identify the plant sex. You can either remove the male plants from your grow area entirely or isolate them in a separate room or tent with a separate ventilation system.

You should also check your female plants regularly for any signs of pollination, such as swollen calyxes (the base of the pistils) or seeds forming inside the buds. If you find any pollinated buds, you should remove them immediately to prevent further spread of pollen.

Another way to prevent pollination is to grow feminized seeds or clones, which are guaranteed to be female and will not produce any male plants. Feminized seeds are created by applying chemical or environmental stress to a female plant, which causes it to produce pollen that only contains female chromosomes.

When this pollen is used to fertilize another female plant, the resulting seeds will be 99% female. Clones are cuttings taken from a female plant that will grow into identical copies of the mother plant.

What Should You Do if You Find Male Plants?

Here are some possible options:

• Remove it from your grow area: This is the simplest and safest option if you want to prevent pollination and ensure a high-quality harvest of seedless buds. You can identify a male plant by looking for small sacs that form at the nodes of the stems. These sacs will eventually open and release pollen into the air. You should remove male plants as soon as you spot them before they open their sacs.

• Use it for breeding: If you want to create your own marijuana strains, you can use male plants to pollinate selected female marijuana plants and produce seeds. This way, you can combine the traits of different varieties and create new hybrids. However, breeding cannabis requires some knowledge and skill, as well as a separate space for pollination.

• Make hash or edibles: Male cannabis contains fewer cannabinoids than female plants, but they still have some psychoactive and medicinal properties. You can use the leaves and stems of male plants to make hash or edibles, such as butter, oil, or tea. However, do not expect the same effects as from female plants.

• Use it for other purposes: Cannabis is a versatile plant that has many uses beyond its psychoactive and medicinal effects. You can use male cannabis for making fiber, paper, rope, clothing, or compost. You can also use them for ornamental purposes, as they have an attractive appearance and a pleasant aroma.

And Now That You Know How to Sex Cannabis Plants, Let's Get Started on Growing Them

Knowing how to sex cannabis plants is essential for any cannabis grower who wants to harvest high-quality buds. By following these tips, you can ensure that your plants produce the best possible yield and potency, without any unwanted seeds or stress.


The sex of a marijuana plant is determined by its genetics before germination, so there is no way to make a male plant female.

However, some growers use chemicals such as ethylene to induce female-like characteristics in male plants, such as producing buds with low THC content. This is not recommended as it can affect the quality and safety of the cannabis.

To identify the sex of a marijuana plant, you need to look for pre-flowers, which are small buds that appear at the nodes of the plant.

Pre-flowers can show up as early as four weeks after germination, but it may take up to six weeks to see clear signs of gender.

Female pre-flowers have fine white hairs called stigmas, while male pre-flowers have round pollen sacs that look like balls.

The main difference between regular and feminized is the sex of the plant that will grow from them. Regular cannabis seeds can produce both male and female plants, while feminized seeds will produce only female plants.

This is important for growers who want to harvest resinous buds, which are only produced by female plants. Male plants, on the other hand, produce pollen sacs that can fertilize female plants and cause them to produce seeds instead of buds.

Regular cannabis seeds are produced by crossing male and female plants, which means they have a 50% chance of being either sex. Feminized-seeds are produced by inducing female plants to produce pollen, which is then used to pollinate other female plants.

This way, the resulting seeds will have only female chromosomes, and will grow into female plants almost 100% of the time. Feminized-seeds are more expensive than regular seeds because they require a special breeding process.

Regular-seeds are useful for breeders who want to create new strains or improve existing ones by crossing different cultivars. They also offer more genetic diversity and stability than feminized-seeds, which may have some hermaphroditic tendencies if exposed to stress.

Feminized cannabis seeds are ideal for growers who want to ensure a high yield of buds without having to worry about identifying and removing male plants. They also save time and space, as they do not require a separate area for male plants or a change in the light cycle from the vegetative stage to trigger flowering.


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