03 ways to determine male and female cannabis plants - Maritime Grown

3 ways to determine male and female cannabis plants

how to tell male or female cannabis plantmale and female cannabis plants

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Getting Started What You Should Know

Look for the balls they say. A cannabis grower must be able to determine male and female cannabis plants in the garden before the males start to cause problems. Buying feminized or feminized auto flowers helps but remember there is a chance of having a hermaphrodite and the rare chance a male. Feminized seeds turning hermaphrodite can be caused by a number of reasons. The most common due to stress, high heat 30 degrees +,  or lights being to close to plants in the first few weeks are common mistakes in the grow room. Hermies can also be transferred in genetics so always keep your eye out when starting new plants. Growing Regular seeds you will usually have 50/50 or 60/40 chance of getting male or females. I found over the years from every 10 seeds I would pop I would get 4 to 5 females from the 10. Growing regular seeds you’re going to need to be able to sex the plants but do not stress it is easier then it sounds. Everyone has their own methods, opinions, and thoughts when it comes to growing and sexing plants these are mine from my personal experiences over the years.

Knowing Your Plants

cannabis preflowerFemale pistilsMale pollen sacs

Before knowing how to sex plants you must know where to look and some of the terminology. The node is the section where the leaf and branch meet the stem.  Preflower, this will be mentioned several times throughout the blog, often referred to elsewhere as the calyx. This is the start of either the male pollen sac or the female reproductive organ where you will look for pistils. Pistils are the reproductive parts of a cannabis plant. The hairlike strands of the pistil tell growers the plant is female and its main purpose is to collect pollen from males.

The Myth Of Telling Sex Of Seeds

sexing cannabis seedsA lot of people still to this day tell me then can sex seeds but I have never met someone willing to bet a $1000 dollars on it lol. Most experienced growers will tell you that you can not tell the sex by looking at the seed. There are a lot of conflicting articles online that say you can by ensuring the seed has a creator at one end that is a circle like the photo above. After reading into this when first starting out I selected seeds using this method and let’s just say things did not go as planned. The information being circulated now is from the same article I read years ago just being reposted and circulated on blogs and websites across the world. I always look before planting seeds and some of the time it works some of the time it doesn’t. I can say most of the time the fems are a particular shape and do have the creator but not all the time.

 Sex plants 7 days after germination

sex cannabis plants in 7 days

Phylos offers to test your cannabis plants using modern molecular genetics and computational biology to tell the difference between male and female cannabis plants as young as 7 days after germination. This requires you to take a sample of the cotyledon leaf, the first round leaf you see when growing from seed. By removing a piece of the round leaf and crushing it into the sample section on your card they can test the sex of the plant. After sending your test to Phylos they will have results 48 hours after receiving. The total cost will be around $100 Cdn to test 4 plants. This is the quickest way possible right now to sex plants at such an early age. I have not personally tried this method but who knows I might try it out in the future so I can write about it and put the results to the test.

  Method 1 Risky To New Growers

Sexing cannabis plants how to sex cannabis plants female cannabis plant how to tell
The photos above are females I took photos of early on they can resemble males

3 ways to determine male and female cannabis plants male cannabis plant determine male and female cannabis plants
The photos above are males that I took photos of early on, they can resemble females.

This method is used by expert growers and talked about online but it is very risky for new growers. I myself use this method only to separate plants in the room into what I think is what but I will never use this method to make the end decision on the sex. I do not recommend this method as some genetics can throw you for a loop or if the male preflower unfolds it can trick you into thinking it is a female. This method can be used to tell the sex of your plants within 4 to 6  weeks of veg. Veg your plants well watching the preflowers. In this case, a magnifying glass or jewelers loop will help to identify the sex. Male plants will show preflowers as early as 3 to 4 weeks into veg where females can take up to 4 to 6 weeks to start showing preflowers. This is where it can become tricky for new growers. When the pre-flower starts the male and females can look the same. As it develops the male’s pollen sacs usually stay roundish where the females pre-flower is round on the bottom and goes into a point on the top similar to a flame or as shown in the photos above. If it is a female you will notice the preflowers with two hair-like pistils coming out of them between the nodes and if it is a male you will see pollen sacs with no hairs. If you have a round sac on one side and a preflower with hairs on the other there is a chance you have a hermaphrodite. Depending on genetics time frames can vary but be sure you wait long enough to be sure a male is a male as I mentioned preflowers usually start out the same and can be confusing at a young age.

Method 2 The Safe Way
best way to tell sex of weed plant best way to tell sex of weed plant

This is the safest way and the quickest to tell the sex of your cannabis plants at home. Again you will be looking for preflowers similar to the method above but they will be more distinguished similar to the photos in method 3. This method requires you to put a black bag over a branch of the plant for 12 hours each day well it is in veg. This will force preflower on this branch only and can allow you to tell the sex within 4-5 weeks of veg. Be sure to keep checking the branch and soon as you determine the sex you can leave the bag off to revert back or cull if it is a male unless you want the pollen. Make sure to test the bag first to ensure no light leaks through. Contractor bags work best they are nice and thick. If need be, double and or triple up the bags to ensure no light leaks through. After placing the bag on a branch you should be able to tell the sex of the plant a lot easier after 7 to14 days. Be sure to support the branch if it is not very thick as the bag adds a lot of extra weight. I personally use this method with great success. The photos above show a branch covered and uncovered.

Method 3 Most Common But Semi Risky 

Female plant preflowers usually go to a point with 2 hair-like pistils coming them.

how to tell female cannabis plant female cannabis plant female cannabis plant how to sex

Male plant preflowers are rounded and can also take on the point similar to females.

male plant how to tell if its a male plant male or female cannabis plant

This is the most common method often talked about online and used by growers worldwide but it is a bit risky for new growers. Simply grow the plants as you normally would. Veg your plants for 3 to 5 weeks or until your ready to flower then flip on to 12 hours light on and 12 hours off. After 7 to 14 days your plant should start showing signs of the sex.  If it is a female you will notice the small preflowers with two hairs coming out of them between the nodes and if it is a male you will see pollen sacs with no hairs. If you see both you could have a hermaphrodite on your hands. This method can be risky to new growers if you’re not checking the plants daily to remove the males in time before they start pollinating. As I mentioned after 7 to 14 days you should easily be able to tell the sex. Some genetics has been known to release pollen in as little as 20 days so do be sure to have the males separated after 15 days of flower to be sure.

Other Methods
Fast growing solo cup

As I mentioned there are lots of methods out there.  Decide on what your end goal is and what your plans are. Methods will change depending on if you plan on growing to crop out, growing to breed or growing mothers to clone.  Another popular method is fast growing plants in solo cups. This can be done with seeds or by taking a cutting off your plant and fast growing it out. This method works well when growing mothers as it gives them time to get nice and big and healthy.  I personally know a few people who use this method but to me time is everything and it’s more work then method 2 or 3  so I do not use it my self. Having the room can also be another issue when using this method and room is not on my side.


In the end, it’s about finding what works best for you. If you want to know the sex asap and have the money to invest in having your plants tested than method 1 is worth a try. If you wanted to save the money then I recommend going with method 2 or 3. You will have around 2 weeks time after flowering to determine the sex. Some genetics release pollen in as little as 20 days after flowering. Do not be worried just keep a close eye on things and you will notice the differences rather easy.

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Much Respect @NsRob

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9 thoughts on “3 ways to determine male and female cannabis plants”

  1. I do method 3 but I don’t let them go to flower fully . Soon as the show I take them out and put back to veg this takes 2 weeks or less and I do this when they have 2-3 nodes. I give them 2 weeks in veg to make sure they are converted back to veg before taking cuttings. No time loss

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  3. My plants are 3 feet tall and they all look the same, lol so I’m thinking they must all be male because my luck isn’t good enough for all 4 of them to be female. I’ll let them grow anyway I suppose. I planted mine outdoors, but I’m in the city and the alley light’s prevent complete darkness! Too late to pot them, they are huge. Should I put a black bag over them at night?

    1. Hey Kat,

      Can you send us some photos of the plants to admin@maritimegrown.com we can tell you if they are males or not. If yo do not see balls hanging or starting by now good chance they are female. As far as the bag goes you should not need that they will go into flower as the days get shorter.

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  6. Thanks for a great article,
    I’m a little stumped on one plant I have.
    It’s grown from a single seed from my first time growing last year.
    The mother plant was a feminized purple power seed but I believe it produced this one seed as a result of stress.
    1 seed in about six ounces!
    As I’ve read online many times a stress produced seed would be a female seed?
    So I’ve grown it this year.
    It’s bushy and looks just like its mother but is alot bigger than the mother was at this time of the year ( I’m getting alot better at this)
    But there are many pre-flowers now, they don’t look like balls….more so brackets that have hair on them but no pistils yet.
    This isn’t how it’s mother grew.
    So I may have trained a male very well.
    I’m just confused as anything.
    Flowering should start within the week as it’s outdoors.
    Please help 🥺

    1. Usually if the seed was from a female plant that stressed the seed will have hermaphrodite traits and some of the plant will have seeds and some wont. if you can send us some photos of the plant to admin@maritimegrown.com we can take a look for you and give your are thoughts on the plant.

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