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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

125 thoughts on “How to Sex Marijuana Plants

  1. April Estep says:

    I love all the info. Thanks good luck to everyone

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    Rating: 0 (from 2 votes)
  2. Connie says:

    Do you need to top your plant or just let it go

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    Rating: 0 (from 0 votes)
    • April Estep says:

      I top mine soully for the purpose of smaller bushier plants that are easyi

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      Rating: 0 (from 0 votes)
  3. Connie says:

    Do you need to top your plants or just let them go.

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    Rating: +4 (from 8 votes)
  4. CindylouCo says:

    I’m in Colorado totally legal here 🙂 I’ve got 9 plants going 4 clones for hubby and me
    Three flowering now today is the first lights out night for those
    The leaves are the size of my hand so wish me luck

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    Rating: +1 (from 1 vote)
  5. Liz says:

    Hello! I’m a first time grower as well and i planted about a dozen seeds on April 1st and right now they are about two inches high with four leaves at the top, two ovel shaped and two what looks like oak leaves. I’m kind of on a budget. Right now I have them inside under a 50 wait plant light. They seem to be growing good but I really don’t have a clue what I’m doing. I guess I’m just hoping for the best. I have been reading up as much as I can on the subject. Any pointers please??

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    Rating: -4 (from 12 votes)
  6. 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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    Rating: +3 (from 11 votes)
    • 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: 0 (from 4 votes)
    • 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 3 votes)
  7. 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 17 votes)
  8. 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: +8 (from 12 votes)
    • david says:

      I was gonna see if someone could help me tell male from female as well.

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      Rating: 0 (from 2 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: -4 (from 18 votes)
    • Cody says:

      JD your plant is a hermaphrodite

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      Rating: +7 (from 9 votes)
  9. 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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    Rating: +2 (from 10 votes)
    • 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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      Rating: +2 (from 12 votes)
    • mUNCHYGIRL says:


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  10. 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: +5 (from 13 votes)
    • Elsie ChipOil says:

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

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      Rating: +5 (from 9 votes)
      • Aaron says:

        It’s illegal here in the us to…. Well most of it, espically if you on gulf coast

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        Rating: +5 (from 7 votes)

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