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How to Sex Marijuana Plants

Marijuana Preflowering

Although generally considered one of the trickiest parts of growing your own marijuana, sexing is quite straightforward and will become easier as you gain more experience. The reason for sexing your plants is so that you can remove male plants before they have a chance to pollinate the females. If this occurs the females will start to develop seeds and this will divert their energy from THC production. Pollinated weed is still smokable, we’ve all had weed with seeds, but the potency will be significantly decreased.

Careful observation of flowering is the only true way to sex your plants, although you may get a clue from their growth patterns. Male plants tend to be leggier than female plants with a longer internodal length. Female plants are squatter with more leaves and a bushier aspect.

Towards the end of the summer, as the hours of daylight decrease, changing light levels will trigger your plants to produce flowers. The appearance of pre-flowers at branch junctions is what you are looking for.

Male pre-flowers should be clearly visible to the eye, although a magnifying glass will make your job easier. Male flowers form at the junctions of the branches and stem and the pollen sacs form little balls.

How to sex marijuana plants

Female pre-flowers will also form at the junction of branches and stem and will normally start to form at the fourth or fifth branches up from the base. They are easily distinguished by the appearance of pairs of tiny white hairs, known as pistils.

Marijuana Preflowering

At this stage your plant is just about to enter the flowering phase of growth and now is the time to remove the males if you wish to.


As the plant enters the flowering stage its growth patterns and nutrient requirements will change. The vigorous vegetative growth will slow, stems will elongate and flower formation will begin rapidly at first before slowing. Your plant now needs less nitrogen but more potassium and phosphorous so now is a good time to add some ‘super bloom’ fertilizer. Follow the packet instructions for fruiting or flowering plants.


The female flowers will start to form kolas around the branch junctions with a main one at the growing tip of the plants. If you look closely you will see the seed pods and these will swell; either with seeds if your plant has been pollinated or with THC as false pods if you have removed the males.


As the flowers become ready for harvest the pistils will darken and the seed pods will be swollen and sticky with resin and THC trichomes.

Ready to harvest

HowtoGrowMarijuana.com has a wealth of information for growers. We hope you now understand how to sex your marijuana plants. It might be worth reading some of the questions and answers made by our visitors below.


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From the forum

How to Grow Marijuana Forum - Growing Marijuana Indoors & Hydroponics

108 thoughts on “How to Sex Marijuana Plants

  1. Chris says:

    Hey I just planted some killer seeds around May 1 any way I can speed the process up and also keep them healthy they are about 1-2″ tall any tips?

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    • soph says:

      Get rocket fuel for veg its amazing and then top shooter for bud it in recreasez yeild 30% well worth the money

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      Rating: +1 (from 1 vote)
    • william says:

      put them in a smaller pot or even in a red solo cup make holes on the bottom and sides about the size of a nickle put stirowfoam in cup not to much then pro mix (dirt) in cup. then go put your little plant in the cup give it lots of sun light then when plant is to big for cup go to the next size up soon you will see a big grow in your plant

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      Rating: +1 (from 1 vote)
  2. casper says:

    my plant is on it 3rd set of 3 leaf n it is growing crazy white hairs does this mean its a female

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    Rating: +9 (from 13 votes)
  3. jd says:

    I have one plant that has the female up top but at bottom it has male parts im tryin 2 figure out if it a female male or hermaphrodite

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    Rating: +7 (from 9 votes)
    • jay says:

      here jd have u still got at plant that u hink is a hermaphrodite if so let it go full term at 12/12 lite’s as all the seeds are all female defo so u got a touch up 1000/seed female yyyyyyyyyyaaaaaaaaaasssssssssssss

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      Rating: -5 (from 13 votes)
    • Cody says:

      JD your plant is a hermaphrodite

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      Rating: +6 (from 8 votes)
  4. Brandon says:

    Would someone mind helping me classify my plants either male or female. I have 4, one is definitely female with the white hairs..but the others look as though they are growing the same white hairs at the end of little sacs. I’m confused as frick, this is my first time growing. Thankyou :)

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    • eric says:

      Brandon, look for the little banana shaped sacks. you have some time to see them before they open. Pollinated seeds is not a bad thing especially if you have quality seeds. I’m doing a full seed run this year. Your first couple of grows is more about the learning experience than the product. Truth is you won’t have the highest quality weed just starting out. Be patient

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    • mUNCHYGIRL says:


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  5. jakes says:

    hi,im jakes from namibia africa..i just planted my seed now with a river pit soil and i hope it will grow outdoor…but it not ligile in our country

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    Rating: +2 (from 8 votes)
    • Elsie ChipOil says:

      Be careful Jakes. It would be horrible to get caught there.

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      Rating: +3 (from 7 votes)
  6. Lillith says:

    Hi all,

    I found wild plants and need a little help!

    Okay I live and work in China as an English teacher with my partner. I live in the south in a small school about 40 minutes walk outside of the town, and we were walking into town for dinner yesterday and came upon 4 wild plants just growing on the side of the road.

    We are trying to determine wether it would be viable to take the plants and replant on our balcony (no one would see because we overlook a mountain and we are the only foreigners in town so not a large social life!) have photos of the plants, but because it’s December I can’t really tell if they are male/female/bisexual …

    Also we want to act on this ASAP because, as the school is still being built, there are a lot of workers around at the moment and we know for a fact they have been smoking … Have come back from class a few times and smelt that sweet sweet aroma with enormous feelings of envy! So we know that someone knows what they look like (and maybe these are the workers plants) and we don’t want to miss an opportunity! We’ve been here 3 years and I’m sure you can imagine what 3 years will do to someone when they love and appreciate the beauty of this plant.

    Any advise would be greatly appreciated! And apologies for the very large post!! Can forward pics if necessary. We are planning to go down tonight and further investigate under the cover of darkness, so as to avoid the suspicions of two foreigners paying very close attention to a bunch of plants on the side of the road!!

    Thanks in advance!! (happy growing to all!!)

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    Rating: +5 (from 11 votes)
    • Leonardo says:

      Well, I’m not there and don’t know your need, but I wouldn’t mess with that stuff in China at all. Those jails are worse than you can imagine and if they think you’re growing it to sell you may be executed.

      Come back to the US when you can and enjoy the herb without such fear.

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    • william BOUT says:

      Omg,u sound like a shill so the legit cause of marijuana/ cannabis is demonized.Your representing the USA teaching in a foreign country an like to know how to make a wise an proper decision?Quit teaching anmove to seatle or the parts of Denver where they need schooling.

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    • Zen says:

      Sounds like a good way to go to jail in China.

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      Rating: +6 (from 8 votes)
    • Patrick says:

      i am sorry i only came across this site now…. if i was you i would take them and replant them…

      i am also an English teacher in China (Shaanxi Province). i moved here just over a year ago… i made a few friends that managed to bring me a parcel of “leaf” – the main stuff we get here where i am is what they call “hash” (fine powder – mid to dark green in colour)

      anyway back to my story … from the parcel i managed to save 7 seeds . when i planted them only 1 has grown ( i am hoping the plant will be bisexual – so i can eventually cultivate more) its gonna be a long process but i am willing to torture myself now for the great rewards in the long run

      if you have taken the plants already and are happily growing them at home

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  7. Larlovesbud says:

    First year, first time grower…. Indoors
    Plant started in May and is 3 ft high.
    Thick leaves, oak size trunk and stems, BEAUTIFUL buds… and it seems VERY healthy…
    Used a combo miracle Grow cactus (for drainage) and miracle soil, as well as fert….
    So, now the bud trichomes are turning red….
    Where do i get the ph balanced water for flushing… I have to be close to harvest..?

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    • Sylvan says:

      Collect rainwater. This is usually very pure. pH is normally a little less than 7 due to pollution and natural CO2 in the atmosphere. But in the absence of the pH balanced water you refer to. it would certainly help.
      Tap water can also be left to stand for a day or two to allows contaminants to either settle or evaporate.

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    • Paw Paw Poppie says:

      Last response was to wrong post.

      Just use distilled water.

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    • Paw Paw Poppie says:

      Its probably rag/dirt weed. Filled with seeds and will give you a bad head ache. Odds of finding a grade weed just growing on the side of the road are slim to none.

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  8. paula says:

    how do you know when to take male away from female,to have no seeds?

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    • professor says:

      as soon as you know it’s a male ….it’s taking up space and it may be keeping your girls from more light

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  9. james says:

    hi im a first time grower when should i start to germantie my seeds ?

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    Rating: +4 (from 6 votes)
  10. Ming says:

    Is the girl scourt cookie with seed? I have the cookie flowering for ten weeks and now I get the harvest. But my staff come with some seed in the flower

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    • Paw Paw Poppie says:

      No, none come with seeds. Seeds are produced when the female plant is breed with the male plant.

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