Want a Grow Sensor?
Get early access to the now.

Early signs of male plants: Learn what you need to look for

Tom Starley
June 10, 2024
8 min read time
A close up of early signs of male plant in a cannabis grow room.
A close up of early signs of male plant in a cannabis grow room.
Download your free VPD calculator
Oops! Something went wrong while submitting the form.

For cannabis growers, recognising the early signs of male cannabis plants is critical: missing them could mean a grow room overrun with seeds and significantly lower yields. 

Failing to identify and separate male plants early can compromise your entire crop, turning potentially rich, resinous buds into less potent, seed-filled flowers. 

Fortunately, this guide is crafted specifically for you, detailing precisely what you need to look for from germination to the pre-flowering stage. 

This post will take you through the signs of male cannabis plants, from spotting the initial pre-flowers to differentiating subtle differences between male and female plants characteristics. 

Equipped with clear instructions and expert tips, you'll learn how to maintain a productive growing space, ensuring your plants develop to their full potential.

Disclaimer: Any information given on this site is for educational purposes only. Please ensure if you’re growing cannabis, you’re doing so by the law and subject to appropriate permissions and licenses of the applicable country.

Grow the best cannabis with the Grow The Best newsletter. Learn how to identify Early signs of male plants.

Understanding cannabis plant sex: The basics

Cannabis plants are naturally dioecious, meaning they develop as either male or female. 

This distinction is crucial for you as a grower because exclusively female plants produce the cannabinoid-rich buds sought after for their therapeutic and recreational properties. The male counterparts have a much lower THC content.

A male cannabis plant will produce pollen sacs that are necessary for breeding but can be detrimental to yield if your goal is bud production.

Male plants are identified by their pollen sacs, which they develop to spread pollen to female plants. 

When a female cannabis plant is pollinated, it shifts its energy from producing buds to producing seeds, resulting in a significant drop in the quality and quantity of the harvestable buds. 

Understanding how to determine cannabis plant sex early on in the growth cycle allows you to segregate or remove males before they reach maturity and pollinate females.

A hermaphroditic cannabis plant.
A female cannabis plant showing hermaphrodite male pollen "bananas".

Hermaphroditic plants, which contain both male and female reproductive organs, can also occur, especially under stress or genetic conditions. 

Hermaphrodite plants have both male and female flowers. They can self-pollinate to produce seeds and pollinate other female plants in your garden, which is generally undesirable unless seed production is your goal.

A female cannabis flower full of seeds
A female cannabis plant full of seeds.

Early identification and management of plant sex are essential for optimising your harvest.

By keeping only female cannabis plants, unless breeding, you ensure that your grow space will be filled with flowering plants that produce the high-quality buds you desire.

Male cannabis plants in a grow room.

Identifying the early signs of male cannabis plants

Spotting a male cannabis plant early in its growth is key to maintaining a grow that maximises bud production. 

The first signs of male characteristics can appear during the pre-flowering stage, which typically begins a few weeks after germination. Here’s what you need to look out for:

Key indicators of male cannabis plants

Pre flowers

Male pre-flowers are small and round and typically appear at the nodes - the points where the stem of a fan leaf and branches extend from the main stem. These are the beginnings of what will develop into pollen sacs. 

Unlike female pre-flowers, which are characterised by their tiny, hair-like pistils, male plants show something significantly different. They do not have pistils and are more bulbous.

Observing these small details requires a keen eye and sometimes a magnifying glass.

Pollen sacs 

As the plant matures, male pre-flowers evolve into pollen sacs. These sacs eventually open and release male pollen, so it's crucial to identify them before they open. 

These sacs are typically clustered together, resembling a bunch of grapes. They are your final warning sign before the plant begins to release pollen. 

Once these sacs open and pollen is released into the air, it can travel to a female plant and start the seeding process, which diverts its energy from bud production to seed development.

This stage of your grow is critical. Being vigilant and checking your plants regularly for these signs can prevent the accidental growth of seeds in your buds. 

Removing males from your grow area as soon as you identify them ensures that your female cannabis plants can continue to invest all their energy into producing potent, resinous buds without the risk of pollination.

Early signs of a male plant in an indoor cannabis garden.

Differences in growth patterns

During the early stages, a male plant grows taller and faster than their female counterparts. This rapid growth allows them to tower over females, facilitating the spread of their pollen. Males also tend to have fewer leaves than females.

Observing these growth patterns can be another helpful indicator in identifying males early in their development cycle.

By familiarising yourself with these key indicators, you can effectively ensure that male plants are identified and isolated or removed before they can affect the quality of your final product.

Learn more about improving your growing game, and sign up for the Grow The Best newsletter now!

Sign up to The Grow The Best Newsletter.

The vegetative stage: Start looking for signs

The vegetative stage of cannabis growth is a critical period for sexing cannabis plants

During this phase, your plants will focus on growing strong and large, but it's also when you can start spotting the early signs of male characteristics. Knowing exactly when and what to look for ensures a crop without unwanted pollination.


Generally, cannabis plants begin to show their sex about 3 to 6 weeks into the vegetative stage, which follows directly after the seedling phase. 

Regular observation should start as early as three weeks after germination. This early monitoring helps identify male plants before they reach maturity and develop fully functional pollen sacs.

A collection of cannabis seeds

Regular vs feminised Seeds 

If you are growing from regular seeds, your crop will likely contain both male and female plants, and vigilance in sex identification becomes even more crucial. 

Feminised seeds are bred to only produce female plants, which simplifies the growing process but still requires attention. Stress and environmental factors can occasionally lead to the development of male flowers, even on feminised plants.

In the vegetative stage, make it a routine to inspect your plants closely. A magnifying tool can help you spot the tiny pre-flowers or early pollen sacs indicating a plant's sex. 

A large maple cannabis plant with many pollen sacks.

Actions to take if you identify male plants

Once you've identified a male cannabis plant, acting swiftly and decisively is crucial to protect your female plants and ensure they produce the highest quality buds. Here's what you should do:

Isolation or removal

The most straightforward action is removing male plants entirely from your grow area. This prevents any risk of them pollinating the females. If you're interested in breeding or need pollen for other purposes, you can isolate the male plants in a separate space where it can't affect your females.

Continuous monitoring

Even after initial checks, continuously monitoring your plants throughout their lifecycle is important. Sometimes, plants that initially show female signs can develop male characteristics, especially if they are stressed. Regular inspections help catch these changes early.

Use sex testing kits or expert help

If you're unsure about the sex of a plant, using a sex testing kit can provide clarity. These kits require you to take a small sample of plant tissue. 

You can use them on your cannabis seedlings to help you determine the sex of your plant early on, which is especially useful if you're new to growing or if the plant's sex isn't clearly visible. 

Alternatively, consulting with more experienced growers or experts can also be beneficial.

A close up of a young male cannabis plant.

Preventative measures: Choosing the right Seeds and monitoring

Taking preventative measures from the start is crucial to minimise the risk of male plants disrupting your crop. Here are strategies to help you maintain a female-dominated grow:

Choosing feminised seeds

Opting for feminised seeds is one of the most effective ways to ensure your crop remains predominantly female. 

Feminised seeds are specifically bred to produce only female plants, significantly reducing the chances of male plants developing. 

However, sourcing these seeds from reputable suppliers is essential to ensure their quality and reliability.

Regular monitoring

Vigilance is key in cannabis cultivation. Regularly inspecting your plants throughout their growth stages allows you to spot any early signs of male characteristics or stress-induced hermaphroditism. 

This continuous observation ensures you can take immediate action, such as isolating or removing the affected plants.

Environmental control

Stress can cause cannabis plants, even those that are genetically female, to produce male flowers. 

Maintaining stable environmental conditions in your grow area, such as consistent lighting, temperature, and humidity, can help prevent this. A grow room monitor like the Grow Sensor makes this hassle-free! 

Implementing these preventative measures can significantly increase your chances of a successful, high-yield harvest. 

Ensuring your grow environment is controlled and stable, choosing the right seeds, and keeping a close eye on your plants will help you produce the potent, high-quality buds that are the goal for most growers.


Identifying male cannabis plants early in their growth is crucial for any grower aiming to produce high-quality, potent buds that only females produce.

By understanding the key signs of male plants and taking swift action upon their detection, you can prevent them from pollinating females, which would compromise your crop's quality and yield.

We've covered how to spot the early signs of male plants, differentiate them from females, and take appropriate actions to maintain a female-only garden. 

Remember, the success of your cannabis cultivation largely depends on your ability to monitor and manage the sexes of your plants effectively.

With this knowledge, you can optimise your growing process, ensuring that your garden remains productive and your plants reach their full potential. 

Whether you are a novice or an experienced commercial grower, paying close attention to these details will lead to a more rewarding cultivation experience.

Happy growing!


When can you tell if plant is male or female?

You can usually tell male or female plants apart when they enter pre-flowering.

Look for pre-flowers at the nodes: the preliminary stages of the male flower are small and round and develop into pollen sacs. In contrast, the initial stages of the female flower feature tiny white hairs (pistils).

Can you turn a male plant female?

No, you cannot turn a male plant into a female plant. The sex of a cannabis plant is determined genetically when the seeds are formed and cannot be changed.

How do I tell if my plant is turning male?

Look for early signs like small, round pre-flowers at the nodes to tell if your plant is turning male. These structures clearly indicate a male plant, and they develop into male pollen sacs rather than the white, hair-like pistils typical of female plants.

How can you tell the gender of a seed?

You cannot determine the gender of a cannabis seed just by looking at it. There’s no way of determining the sex of a future plant whilst it’s still in seed form. 

The sex of cannabis plants can only be definitively identified as they mature and begin to show either male or female pre-flowers, usually a few weeks after germination.

What does a male pre-flower look like?

A male pre-flower looks like a small, round, bulbous structure that forms at the plant's nodes. Unlike female pre-flowers, which look like white hairs, male pre-flowers are solid and will eventually develop into pollen sacs.

Do male plants produce buds?

No, male cannabis plants do not produce buds in the way female plants do. Instead, males produce pollen sacs necessary for pollinating female plants and seed production. 

Female cannabis plants are the ones that develop buds, which contain the majority of cannabinoids like THC and CBD that are sought after for recreational and medicinal use. 

If you're growing female cannabis for bud production, it's important to identify and often remove males early in the growth process to prevent them from pollinating females, which would lead to seeded buds.

How far away can a male plant pollinate female cannabis plants?

Under the right wind conditions, a male cannabis plant can pollinate a female cannabis plant from up to several miles away. Typically, pollen can travel substantial distances, making the isolation of male and female plants important in controlled growing environments.

Join the grow the best cannabis newsletter today!
Share this post
Tom Starley
June 10, 2024
8 min read time

Get your free VPD & environment calculator

Perfect your environment.
Stay in the VPD sweet spot.
Ideal temperature ranges for day & night.
Prevent mould.
Induce colour.
Grow the best plants.
We care about your data in our privacy policy.
Your download will land in your inbox shortly.
Oops! Something went wrong while submitting the form.
Screenshot of our FREE VPD chart and environmental calender
Monitor your grow rooms with the Grow Sensor. Access grow room data anywhere, anytime.
We care about your data in our privacy policy.
😉 You have been added to the waiting list.
Oops! Something went wrong while submitting the form.
The Grow Sensor hanging in front of an iPhone displaying an overview of all grows within the Grow AppArrow
Get your FREE impartial list of the best grow room sensors now. Buy the right sensor for your grow room environment.
Sort by price.
Compare features like CO2 & VPD.
Includes affordable & premium sensors.
Check availability in your location.
Make an informed decision.
We care about your data in our privacy policy.
😉 It's on the way to your inbox.
Oops! Something went wrong while submitting the form.
The grow sensor hanging from its cable.
Grow the best plants with your FREE CO2 calculator.
We care about your data in our privacy policy.
😉 It's on the way to your inbox.
Oops! Something went wrong while submitting the form.
The grow room CO2 calculator.
Our blog

Latest blog posts

Get the latest grow news, tips and tricks here.
Grow the best - how the grow sensor handles vpd
Grow The Best

The Grow Sensor and VPD

Mastering VPD is essential for optimal plant growth. Learn how to manage it effectively now.
User avatar
Drew Cano
11 Jan 2022
5 min read
Learn your cannabis grow acronyms
Grow The Best

Learn your cannabis grow acronyms

Indoor growing has many acronyms. Learn key terms for better plant growth.
User avatar
Drew Cano
11 Jan 2022
5 min read
A grower holding some of the best soil for cannabis.

Best soil for cannabis: What every grower should know

Find out the benefits of using the best soil for cannabis and how to create your own perfect soil
User avatar
Drew Cano
11 Jan 2022
5 min read
Grow The Best

Embrace your grow style

Growing cannabis requires patience and learning. Explore different styles and techniques now.
User avatar
Drew Cano
11 Jan 2022
5 min read
Man inspecting cannabis plants grown outdoors on a farm

When does flowering start outdoors: The cannabis edition

Master outdoor cannabis flowering: Timing, tips, and more
User avatar
Drew Cano
11 Jan 2022
5 min read
A cannabis calcium deficiency in a large cannabis leaf.

Cannabis calcium deficiency. Causes, signs & solutions

Learn to spot, treat, and prevent calcium deficiency in cannabis for healthier plants.
User avatar
Drew Cano
11 Jan 2022
5 min read
An autoflower cannabis plant.

2024 guide: Autoflower vs photoperiod cannabis plants

Explore key differences and tips for autoflower vs photoperiod cannabis.
User avatar
Drew Cano
11 Jan 2022
5 min read
Male cannabis plants in a grow room.

Male cannabis plants: Identification, uses and benefits

Explore the role and uses of male cannabis plants.
User avatar
Drew Cano
11 Jan 2022
5 min read