How to identify male vs female cannabis plants (with pictures and tips for hermaphrodites)

Last updated and expanded: August 2025

TL;DR

Learn how to spot early signs of male, female, or hermaphrodite cannabis plants so you can prevent unwanted pollination and grow high-quality, seedless buds.

• Female cannabis plants develop a teardrop-shaped calyx with two white “hairs” (pistils).
  
• Male cannabis plants grow smooth, oval-shaped pollen sacs.
  
• Hermie cannabis plants show both flowers (sex organs) on one plant and can self-pollinate.

Many growers wonder how to tell the sex of their cannabis plants, especially in the early weeks of growth.

In this guide, you’ll learn to recognize each type so you can act quickly and protect your harvest.

Why identifying cannabis plant sex matters for your harvest

Cannabis plants can be male, female, or, in some cases, hermaphrodites.

Like many other flowering plants, cannabis reproduces when pollen from male or hermaphrodite flowers reaches female flowers. 

When a female cannabis plant is pollinated, the female flower begins producing seeds instead of focusing on bud growth.

This results in smaller, less potent buds and a significant decrease in yield.

Female plants that avoid pollen will continue building thick, aromatic buds with high cannabinoid content, exactly what most home growers aim for.

For this reason, male and female plants are typically grown separately, unless the goal is to produce seeds or collect pollen for breeding purposes.

Cannabis flowering time: when and how it begins

Photoperiodic cannabis plants will not enter the flowering stage unless they receive 12 hours of uninterrupted darkness and 12 hours of light each day.

If you keep your plants under a longer light cycle (18/6), they will stay in the vegetative stage, continuing to grow in height and size.

You can extend the vegetative stage to grow larger plants, but once you switch to a 12/12 light cycle, flowering begins, and preflowers will soon appear.

Outdoors, photoperiod cannabis plants begin flowering naturally as days get shorter, usually in late summer or early autumn, depending on your location.

To trigger flowering indoors, switch your light cycle from 18 hours of light to 12 hours of light and 12 hours of complete and uninterrupted darkness.

To learn more about how light schedules affect cannabis growth and flowering, read our growing guide on photoperiod lighting.

First signs of the flowering stage: solitary flowers or “preflowers”

The first sign that a cannabis plant is entering the flowering stage is the appearance of solitary flowers, commonly known as male or female “preflowers”.

While commonly called “preflowers”, they are actually the first true flowers, appearing before the plant develops full clusters of buds or pollen sacs.

Male vs female marijuana plant: How to identify them

Here’s how to spot male, female, and hermaphrodite cannabis plants early.

When to check

Male flowers usually appear 3 to 4 weeks from germination.
Female flowers show up around 4 to 6 weeks.
Both usually appear when the plant has 5 to 6 internodes.

Do male cannabis plants show sex earlier than females?

Male cannabis plants often show their sex earlier than females, sometimes by a full week. This early development helps growers identify and remove males before they release pollen.

Where to look

Preflowers develop where the branches meet the main stem, especially in the upper parts of the plant, close to the lights.

What to look for

• Female plants: Look for a small green calyx with two white hairs (stigmas) forming a V shape. These are the early signs of buds.
• Male plants: Look for small “oval-shaped balls” that later form clusters of bell-shaped flowers.
• Hermaphrodites: Look for yellow banana-shaped anthers growing from buds, often due to stress.

Female cannabis plants: what do preflowers look like?

Female‌ solitary flowers or “‌preflowers‌” ‌look‌ ‌like‌ ‌a‌ ‌pair‌ ‌of‌ ‌white‌ ‌hairs (stigma) coming out from a green, drop-shaped calyx. This structure is also known as “pistils”. 

Female cannabis plants typically reveal their sex between weeks 4 and 6 from seed, when small preflowers begin to form at the nodes.

Female cannabis plants can be grown from regular photoperiodic, autoflowering, or feminized seeds.

Many of these small flowers growing together will become the “buds”, which ‌contain‌ ‌the‌ ‌largest‌ ‌cannabinoids’‌ ‌concentration‌.‌

Early signs of a female cannabis plant

The first sign your plant is female is the appearance of a single, small teardrop-shaped calyx with two white hairs (stigmas). These hairs often form a “V” shape and may be easier to spot near the top of the plant where light exposure is strongest.

Unlike male plants, which are usually taller and spindlier, females tend to grow bushier with more side branches.

These flowers appear at the node where a branch meets the main stem. 

Male cannabis plants: photos week by week

Male cannabis plants develop small, oval-shaped structures at the nodes that look like little balls, with no hairs involved.

These are pollen sacs, not buds, and they contain pollen grains but no trichomes. 

Once the pollen sacs open, they can pollinate not only your plants but also those growing nearby.

Male plants cannot produce smokable flowers. Their role is to release pollen and pollinate female plants, which leads to seed production and reduces the size and potency of your harvest.

Early signs of male plant

Cannabis male solitary flowers or preflowers appear earlier and develop faster than female ones. They can appear at week 3 of the vegetative stage.

If you are not breeding for seeds, remove male plants as soon as you recognize them to avoid accidental pollination.

To identify male plants early, look for taller, less bushy growth and fewer side branches.

Late signs of male plant

In the late stages, male plants develop clusters of pollen sacs that open fully, releasing a yellow cloud capable of pollinating any nearby females.

What should I do if I find a male cannabis plant?

If you find a male cannabis plant in a grow meant for seedless buds, remove it immediately.

Male plants release pollen that pollinates females, leading to seeds instead of high-quality buds. Carefully bag and discard males to prevent pollination.

Hermaphrodite cannabis plant: how to identify hermies and what to do

A hermaphrodite cannabis plant, or “hermie”, develops both male and female flowers on the same plant.

Sometimes they develop male flowers in the shape of “bananas” on the female buds.

Hermie plants can produce pollen, which may lead to seeded buds and reduced potency.

This can lead to self-pollination and the production of seeds, which reduces bud quality and potency. Even worse, it can release pollen and pollinate nearby female plants, affecting your entire crop.

Always inspect your plants closely, especially if they have been exposed to stress.

If you spot a hermie, it’s best to remove it immediately to avoid pollination.

Seeds produced by hermaphrodite plants are more likely to develop into hermies themselves in future grows. 

Early signs of hermie plant: photos week by week

Early signs of a hermie plant include small pollen sacs forming at the nodes, often appearing alongside white pistils.

These sacs resemble tiny, oval-shaped balls and may develop on short stalks.

These early indicators of hermaphroditism usually appear during the flowering stage if the plant has been exposed to factors like light leaks, heat stress, or physical damage. 

Late signs of hermie plant: bananas or “nanners”

Even after confirming a plant is female, it is essential to keep checking during flowering. 

In some cases, yellow banana-shaped anthers can emerge directly from female buds, especially in response to heat stress.

Some plants can develop male flowers later in the cycle, so regular inspection is key to preventing accidental pollination.

What are “bananas” or nanners on cannabis buds?

Sometimes, female cannabis plants can develop small yellow structures that look like tiny bananas on the already formed buds.

These “bananas” are anthers, part of the male flower that carries the pollen, and are a sign of hermaphroditism.

Unlike full male flowers in female plants, these “nanners” grow directly from female buds and can release pollen very fast.

If that happens, nearby female plants can get pollinated and start producing seeds, which often carry hermaphrodite traits. Keep a close eye on your buds in the final weeks and remove any buds with “bananas” you see before they open.

Hermie plant: what to do

If male flowers resembling “bananas” appear on a single bud, you can try removing that bud, especially if it suffered direct stress from a light burn, but keep monitoring the rest of the plant for new nanners.

If nanners appear across many buds, it’s often best to remove the entire plant to avoid pollinating the rest of your crop.

Common causes of hermaphroditism in cannabis plants

Hermaphroditism in cannabis is often triggered by environmental or physiological stress.

Common causes of hermaphroditism include high temperatures, light leaks during the dark period, nutrient deficiencies, root rot, and other forms of stress such as over- or underwatering. 

In some cases, hermaphroditism is linked to poor genetics or unstable seed lines.

To reduce the risk, keep environmental conditions stable, avoid stressing your plants, and choose seeds from reliable sources when possible. 

This is especially important when growing photoperiodic or unknown seeds, where the outcome is less predictable.

Tip: Don’t confuse stipules with preflowers

Preflowers can be mistaken for stipules, which are small, pointy leaf-like structures near the nodes.

Stipules are present on all cannabis plants, male, female, or hermaphrodite, and do not indicate plant sex; they are just pointy leaves

If you’re unsure, keep watching closely; true preflowers will become easier to spot within a few days.

Bonus: These plants may look like hermies but they are not! (pics)

Understanding cannabis flowering beyond the 12/12 light cycle

Nowadays, the 12/12 light schedule is more of an industry convention than a strict biological requirement for all cannabis varieties. The “critical day length” varies by genetics and even among individual plants within the same seed population. 

Many cultivars can initiate flowering with more than 12 hours of light, some with up to 15 hours, while autoflowering types are completely day-neutral and will flower under 24 hours of light. 

There are also varieties with very long critical photoperiods that remain vegetative at high latitudes but begin flowering immediately at lower latitudes.

Understanding the critical photoperiod of each cultivar and matching it to your latitude and growing conditions allows you to optimize plant size, cycle timing, and yield.

This is key whether growing outdoors or under controlled lighting indoors or in greenhouses.

Sexing cannabis plants: Summary and FAQs for home growers

How can I tell if my cannabis plant is male or female?

You can tell the sex of a cannabis plant early by looking at the nodes where branches meet the main stem. Female plants form individual flowers (pre-flowers) with a small calyx that may show emerging white pistils (stigmas), while males develop oval-shaped, smooth pollen sacs without any hair-like growths.

When can you determine the sex of a cannabis plant?

You can usually determine the sex of a cannabis plant between weeks 3 and 6 of growth, once solitary flowers or “pre-flowers” appear.

Early detection is possible by closely inspecting nodes with a hand lens to see either pistils (female) or pollen sacs (male).

Do feminized seeds guarantee female plants?

Feminized seeds are bred to produce nearly 100% female plants, greatly reducing the chance of males.

However, severe stress, like extreme heat, can still cause a feminized or autoflowering seed to develop hermaphroditic traits, so monitoring plants during flowering remains important.

Can stress affect the sex of a cannabis plant?

Stress can influence sex expression, especially in genetically unstable plants.
Factors like irregular light cycles, nutrient deficiencies, high heat, or pruning damage can trigger hermaphroditic traits, leading to hermaphrodite plants that may produce seeds.

Can cannabis plants change sex?

Yes, cannabis plants can change sex under stress, becoming hermaphrodites. If a plant develops both pollen sacs and pistils, it can self-pollinate, producing seedy buds.

Those seeds will likely become hermaphrodites, so they are not valuable. Stress factors like light leaks, pruning mistakes, or extreme temperatures can trigger this change.

Can cannabis plants reverse sex to produce feminized seeds?

Yes, female plants can be treated with substances like colloidal silver to produce pollen sacs (becoming hermaphrodites). This pollen is then used to pollinate (fertilize) other female plants, producing feminized seeds. It’s a controlled process, not spontaneous.

What if no sex signs are visible by week 6?

If a cannabis plant grown indoors does not show any sex signs by week 6, it may need a change in the light schedule to trigger flowering. 

Switching to 12 hours of light and 12 hours of uninterrupted darkness usually initiates this process.

Outdoors, it is normal for a plant to go through the entire summer without showing sex if daylight hours remain long. In these cases, preflowers tend to appear naturally as the days get shorter later in the season.

Key Takeaways: why plant sex matters

Identifying the sex of your cannabis plants early helps you avoid pollination, preserve bud quality, and prevent unwanted seeds.

Check the nodes for preflowers around weeks 3 to 6, and remove any male or hermaphrodite plants as soon as they appear.

With regular inspections and stable growing conditions, you’ll stay on track for a seedless, high-potency harvest.

The Cannabis plant life cycle – Cannabis stages week by week

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