Only a female marijuana plant makes flowers/buds that contain a usable amount of THC. Male marijuana plants only make pollen to fertilize the females with. Most growers will throw away any male plants that they encounter to keep them from fertilizing the female plants. If your female plants do get fertilized, they will use all their energy to produce seeds instead of making buds. This is good if you want seeds, but you will run into the same problem since half of the seeds will also be male.
Female marijuana plants make buds.
Male cannabis plants make pollen sacs (low THC compared to buds, bad to smoke, low yields if used for concentrates). Avoid keeping male plants in your grow room because their pollen causes buds to form seeds.
The best way to ensure all-female cannabis plants is to use feminized seeds. Feminized cannabis seeds are safely available worldwide in just about every country. If you grow with feminized cannabis seeds, every plant will be female and grow seedless buds. Highly recommended over using seeds you find, which are on average going to be half male plants.
If you would like to start a breeding program to make your own hybrid, try using a method that creates all-female (feminized) seeds at home so that you don’t waste time having to identify and throw out male plants.
Getting clones of female marijuana plants is a way besides buying feminized seeds online from a seed bank to ensure that all your marijuana plants are female.
If you don’t have a choice of seeds, and some of your seeds may be male (like if you just found seeds) then you want to get your plants to reveal their sex right away so you don’t have to waste time and energy on male plants.
Click here for pictures of male and female marijuana plants.
How to Identify the Sex of a Marijuana Plant
1.) Take a cutting (clone) from the unverified marijuana plant.
I take stems off the plant and put them in a glass of water (learn how to make clones in a cup of water). Some growers use an aerocloner but that is unnecessary work because you don’t need your cuttings to make roots. As long as you keep a clone in a cup of water with light, it should stay alive long enough to do this process. If you have extra stems, you can take multiple cuttings and put them in the same cup. Some cuttings will show their sex sooner than others, so if you put a bunch in the same cup you may get the sex faster.
2.) Label both the clone and the mother plant with the name of the strain so you know which clone came from which corresponding mother plant.
I use disposable cups and write the name on the cup. You could also put a piece of tape on a cup and write the name on that. You should do this step if you’re identifying the sex of more than one marijuana plant at a time. If you don’t label your clones, then all your effort will be for naught because you won’t know which clone is which!
3.) Give clones a light schedule with 12+ hours of darkness every day to initiate flowering and get the cuttings to reveal their sex.
Again, you don’t need to wait for the clones to establish roots before you start this process. You can start this immediately after you take the cutting. The cuttings will start flowering even if their roots haven’t formed yet. However, you should make sure they get at least some direct light during their “day” to keep them healthy long enough to reveal their sex.
4.) Clones will reveal their sex in 1-3 weeks.
Look to the joints where leaves meet the stem. Males develop balls and females develop white hairs. Click here for more information and pictures about how to sex a marijuana plant.
Female marijuana plant – The first flowers of a female cannabis plant looks like this. You will see white hairs coming where leaves meet the stem.
Notice the white wispy hairs at the “joints” where the leaves meet the stem.
This is what female cannabis flowers look like at the top of the plant. You will notice white hairs emerging from the leaves.
Male marijuana plant – The first flowers of a male cannabis plant look like this. You will see little balls, like grapes, that appear in the same place as female plants. Male pollen sacs often also appear at the top of the cutting.
Male pollen sacs are tiny and hard to see at first, but pollen sacs quickly start growing in bunches that are easy to identify.
Here are male pollen sacs after they start growing in bunches. You know for sure this is a male plant when you see bunches of balls without any white hairs.
5.) Remove male marijuana plants.
Once you have determined the sex of your clones, you should make sure you throw away any corresponding male plants. Or at least move them to somewhere safe so their pollen can’t get to the buds of your female cannabis plants by accident.
Now you can grow your known-female cannabis plants with confidence. Once they start flowering, they will make the same type of flowers as the cuttings you took. Continue to care for your female cannabis plants with a ton of light, no nutrient deficiencies, consistent 12-hour dark periods, and don’t let them get hot during the last 2-3 weeks before harvest.
Mission Complete: You know the sex of your cannabis plants and have only bud-making plants left!
Yay for cannabis buds!
Click here for a list of recommended beginner marijuana strains (all-female seeds unless otherwise indicated)
