by Nebula Haze
Male cannabis plants don’t make buds, only female cannabis plants make buds. Yet naturally, with regular cannabis seeds, about 50% of cannabis plants end up being male.
Cannabis Sex Matters: Female Buds vs Male Pollen Sacs (click for closeup). Male plants don’t make buds!
Only female cannabis plants make buds. Male plants produce pollen sacs that are low in THC, not good to smoke, and cause nearby female buds to grow seeds.
Unfortunately, male pollen sacs are not useful to most home cannabis growers unless you’re a breeder. Identify and remove male cannabis plants ASAP.
When pollen sacs open up, they look like white, yellow, green, or purple flowers (pretty!), but they spread pollen everywhere, which pollinates your female plants. Not good for bud quality. Additionally, male pollen sacs are harsh to smoke and don’t contain high levels of THC or other cannabinoids.
Male pollen also causes female plants to produce small yields of lower-potency, seedy buds. Most home growers should try to get male plants out of the grow room as soon as possible.
How to tell if a cannabis plant is male or female before flowering?
Visually, you usually can’t tell the difference between male and female plants until they start flowering (making either male flowers/pollen sacs or female flowers/buds), especially when it comes to younger plants.
There are 3 main ways to tell a marijuana plant’s sex while it is still in the vegetative stage.
As a result, most cannabis growers identify and toss male plants as soon as possible. That means for a home cannabis grower starting with regular seeds (for example, seeds you find in your weed), about half of your plants won’t make buds and will need to be tossed. Those are terrible odds, and as a grower, you deserve better.
Luckily, there are 3 different ways to determine cannabis plant sex before the flowering stage, but only one way to ensure that all your plants are female. It’s important to get rid of any male plants as soon as possible, because not only do they take up room that could be filled with bud-making plants, the pollen released by male cannabis plants will pollinate all your female plants and cause seedy buds.
3 ways to tell if a plant is male or female before initiating the marijuana flowering stage
- Start with feminized seeds (or female clones) – Best for most home cannabis growers. Starting with feminized seeds or female clones from a trustworthy source guarantees that 99.9% of cannabis plants end up being bud-making female plants.
- Genetic testing – Send a piece of a leaf from your young plant to a lab to test for the sex. This can be expensive and is often not 100% accurate.
- Examine the “pre-flowers” – Look at the cannabis pre-flowers (little versions of male or female flowers that sometimes appear in the vegetative stage at the joints where the fan leaf meets the stem). This technique works better for some cannabis strains than others, as some plants start growing pre-flowers within 3 weeks of germination, while others may not grow any pre-flowers until 6+ weeks after germination. Pictures below.
1.) Start with feminized cannabis seeds (or female clones)
This is the best option for most home cannabis growers. Starting with feminized seeds or female clones guarantees 100% of cannabis plants are bud-making female plants. The good news is that feminized cannabis seeds are widely available almost anywhere in the world. Learn more about feminized cannabis seeds.
Learn where to safely buy cannabis seeds online.
2.) Genetic testing
You can send a piece of a leaf from a 3-week old cannabis seedling and get them to do a genetic test to determine if it’s male or female. The downside of this technique is cannabis genetics are a bit odd. Plants don’t always have neatly separated male and female chromosomes, which means lab testing can occasionally produce false positives and negatives. In other words, some plants marked as “female” may be male, and some plants marked as “male” may actually be female. Some plants may end up being hermaphrodites. However, lab testing is used by some commercial growers as it does greatly increase the chance that all plants end up being female.
You usually can’t look at a cannabis plant this young and tell if it’s male or female, but a genetic test from the lab can sometimes give you a clue…
3.) Examine the “pre-flowers”
The usefulness of this last method depends heavily on your genetics, as some strains show pre-flowers at a very young age, while others may take weeks or months before they reveal their sex via pre-flowers n the vegetative stage. Male plants tend to show their pre-flowers before female plants.
Essentially, the goal with this method is to examine the vegetative cannabis plant at future bud sites, where pre-flowers can grow, and look for early signs of male or female plants. Pre-flowers are small buds/pollen sacs that develop at the nodes (the junction where the stems and leaves meet) while the plant is still in the vegetative stage.
The base of a leaf is the best place to look for pre-flowers. Pre-flowers appear as soon as 3 weeks from germination for some strains. However, some strains may take 6+ weeks before they produce pre-flowers.
Look for pre-flowers at the base of the leaf. Typically males show before females.
This is what male vs female cannabis preflowers look like.
Female pre-flowers will also produce wispy white “hairs” that emerge. If you see these white hairs, that means you’re looking at female pre-flowers.
If you see bunches of balls, you know for sure you’re looking at male pre-flowers. However, it’s extremely rare to see more than 1-2 pollen sacs per joint when the plant is still in the vegetative stage.
Hint: Male cannabis pre-flowers tend to be shaped somewhat like a spade from a deck of cards.
Here is a diagram to help you know exactly what you’re looking for. If you see green hairs, those are “stipules” and not pre-flowers. Ignore the stipules.
Read the complete tutorial on how to check male vs female preflowers.
Hermies, bananas, and random pollen sacs
Note: Some cannabis plants produce both male and female flowers. These hermaphrodite plants (affectionately called hermies) should be tossed just like male plants because their pollen sacs also can cause all the buds in your grow room to get seedy if the pollen gets released. Starting with good genetics and taking good care of cannabis plants is the best way to prevent them from “herming”.
If you see a mix of pollen sacs and buds (or little pale or yellow “bananas” growing among the buds), you have a “hermie” which should be treated like a male plant and tossed to prevent pollination.
FAQs (Frequently Asked Questions)
How can I make a male plant female?
- You can’t – There is no safe or reliable way to consistently turn a male cannabis plant into a female cannabis plant. It is a better idea to try to start with all-female plants, or identify and remove male cannabis plants as soon as possible.
What are the early signs of a male plant?
- Spade-shaped “balls” at the joints – Look where leaves meet the stem. If you see “balls” (pictured above) then it is not a female plant.
When can you tell if your plant is male or female?
- 3 weeks at the soonest – 3 weeks from germination is typically the earliest a lab will take a leaf sample from a plant to test for sex. Visually, some cannabis plants reveal their sex as early as 3 weeks from germination via pre-flowers. These appear even in the vegetative stage for many strains. However, some strains may take 6+ weeks before they grow pre-flowers, so this isn’t the most reliable method. Your best bet is to start with all-female plants!
When you know every single plant is female, you can fill your grow space like this and know every plant will make buds.
Summary: How to tell if a cannabis plant is male or female before flowering?
There are three main ways to identify the sex of marijuana plants before they start flowering:
- Start with feminized seeds or clones. This is the best option since it guarantees 100% female plants (as long as you start with a good breeder). Feminized seeds can be purchased from reputable seed banks (currently, I’m using Seed Supreme, though there are many excellent cannabis seed banks).
- Genetic testing can identify sex early on, but results aren’t always accurate. It also tends to be expensive.
- Examine preflowers once they emerge. This works better for fast-showing strains. Check for female wispy white hairs or male spade-shaped flowers at the joints where leaves meet the stem.
While genetic testing and preflowers can help, the ideal solution is to start with feminized seeds or all-female clones. This avoids wasting time and space on male plants that don’t produce buds. Be sure to get feminized seeds from a trusted source and confirm the seller has a solid reputation.
Remove male plants to prevent pollination so you end up with sinsemilla (seedless buds), which are more potent and considered higher quality than seedy buds. Growing only female plants is the best way to guarantee heavy, potent, seed-free yields from your cannabis garden.
About the Author: Nebula Haze
Nebula Haze is an experienced cannabis cultivator and co-founder of GrowWeedEasy.com, the web’s most comprehensive online resource for growing marijuana indoors at home. Since creating the website in 2010, Nebula has dedicated her life to understanding the cannabis plant and teaching fellow growers how to produce huge yields and captivating bud quality at home. Stop paying other people a ton of money for sub-par weed and start growing better weed for a fraction of the cost today!
Check out my easy 10-step guide to growing cannabis.
