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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 plantsFemale 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 PrefloweringAt 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.FloweringThe 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.KolasAs 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 harvestHowtoGrowMarijuana.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. 

125 thoughts on “How to Sex Marijuana Plants

  1. 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!!)

    • 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.

    • 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.

    • Zen says:

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

    • 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

  2. 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..?

    • 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.

    • Paw Paw Poppie says:

      Last response was to wrong post.

      Just use distilled water.

    • 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.

  3. paula says:

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

  4. james says:

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

    • Paw Paw Poppie says:

      Thats up to you, start whenever you are ready to grow.

    • htgadmin says:

      Check out our forum http://forum.howtogrowmarijuana.com
      It’s a great place to ask questions from other growers and join our community

      • Matman says:

        Backyard buds in SoCal. Healthy 18 24 inch plants vegged indoors, I put them out a cpl weeks back. Males showed thr package first and we relocated them to another residence. They looked to good to get rid of small seeds pods but killer flowers developing? Are they worth keeping? Or will I have enough time to harvest both males and females with the light change that’s coming soon! First week in March now.

  5. 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

  6. Shan says:

    Nice now I know how to grow!!

  7. chris rutledge says:

    This is my second year growing. Last year I ended up with one female, and I had planted it too late to get the full grow season. This year I set them out the first week of april and they are 2 plants 9 feet tall. One has wierd leaves. they look like weed the whole way but the leaves are kind of webbed, almost like a maple leaf. I know it is marijuana, you can tell from all the buds, but the leaves are deformed. has anyone else had this happen to them before?
    I also woukld like to know the best way to cure it. Last year it smelled a little homegrowny and I want it to smell skunky, what can I do?

    • Paw Paw Poppie says:

      The smell come from which strain it is, you can not change the smell. The leaves grew like that from the genics of the strain, nothing you can do. Just finish it out.

  8. Glorfindal says:

    I have grown about 24 plants all over 10ft tall growing outside, the only problem i have with detection is other pot heads finding it and stealing it. My concern with my babies is that i cant figure out how old they are and when should i harvest. A quick Answer to my questions would be VERY much appriciated! thank you fellow farmers.

    • Paw Paw Poppie says:

      You will not be able to tell their age. Get a jewers loop and check the trics when they are 25% to 50% amber its time to harvest.

    • Michael Hardie says:

      The idea is NOT to see how tall you can grow the plant. Much better is to use the power of threes. By this I mean cut or “pinch” the tops as they grow. The first set of small round leaves do not count. The next set of leaves that grows on the young plant will look like real marijuana leaves with the jagged edges. The next will be your “second” set. When the third set grows out enough to have a small stem it is time to pinch the top. Use a razor blade or small sharp scissors (I prefer the scissors). This will result in two new sets of branches to replace the one. This means your plant will become wider and not as tall. You repeat this process on the the two new branches. Allow the next set to grow on each one. Then the second. And when the third grows out enough to have a bit of space on the stem then pinch them like you did on the first step. Repeat this one more time. Three sets of new leaves on the new branches and pinch the third. This will result in a bushier plant, give you more buds and allow the plant to put it’s energy into the buds as opposed to just making it taller. It is also much harder to detect as it is not so tall and resembles other plants more so than a plant that simply grows tall. In simple terms, you cut the third set of leaves at the stem and you do this three times. The power of the triangle. I got this tip from a real pro. And it really works.

  9. Newbie says:

    To The Daddy. I’m a first time grower anything that u can suggest.? plant is about 6inchs high

  10. The Daddy says:

    well How about use water and water you mother ******s, Thats how they grow in the wild why the f**k adding s**t is going to make them better,bigger,stronger its all crap, LIGHT,WATER and TLC and end result will be a pure non toxic other than weed it self smoke. Come on stop feeding ppl crap. PEACE

    • Grandpa says:

      I understand your post is rather old but some poor sod might read that tripe and think you actually know what you’re talking about. Perhaps you should do some research before speaking. Plants don’t need nutrients, but they are far less efficient at converting sunlight when nutrients aren’t as available. Adding nutrients allows the plant to grow much faster.

      When growing outdoors, the soil has nutrients in it, adding nutrients can definitely help, but it’s not necessary. When growing indoors, the nutrients are added by the grower because water doesn’t have nutrients in it when it comes out of the tap. Without nutrients, the plant will still be able to do all of the normal things, but it would do it far more efficiently with the nutrients available.

      The natural, ‘non-toxic’ weed you speak of is merely lower potency when compared to pot grown with proper nutrient levels.

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