The Joy of Sex(ing Your Plants)
You may or may not already be aware that Cannabis plants exist in male and female forms. Unless you’re breeding plants, you don’t really want the males hanging around because unpollinated female plants are going to produce your biggest and most potent buds, whereas pollinated females will produce smaller, milder buds that will be full of seeds. As a “budding” grower, you’ll want to separate your males and females prior to flowering. But how do you know which are male and which are female?
There are a few ways to sex your plants with your naked eyes. Some of these methods start when the plants are young and others require a more mature plant. You want to get the males out before they start dropping pollen over your females. So here we go!
Sexing Your Plants (Visually)
Editor’s Note: These are listed in chronological order, not order of effectiveness. It becomes easier to differentiate the cannabis sexes as the plant matures.
Growth Patterns (<2 weeks)
This method is not particularly effective, since plants grown indoors under artificial light won’t necessarily conform to this description, but GENERALLY male plants will grow taller, while female plants can often exhibit more complex branching. However, this behavior might vary from cultivar to cultivar. Additionally, even if you are able to detect these differences early in the life cycle of the plant, it may be too early to be certain and you shouldn’t start ripping out your “males” just yet.
So why did we mention it? So you’ll know better when somebody tells you that this is a good method for sexing your plants.
Maturity Rate (2-4 weeks)
This method requires you to take some notes and keep tabs on your plants, which we generally recommend anyway.
Male plants typically reach sexual maturity two weeks earlier than females. When a male plant begins to mature, its pollen sack will begin to develop. These are sometimes called “false buds.” As mentioned above, male Cannabis plants will typically be taller than females and this fact, coupled with the detection of the developing pollen sacs are a common method to determine the gender of your plants. This method can be used accurately, but the beginning grower may want to get a feeling for the grow cycle before sexing plants this early on.
Flowers versus Pistils (4-6 weeks)
For the beginner, the most reliable method for sexing plants requires an examination of the “pre-flowers” of your plants. We mentioned the males “pollen sack” above and this is still a good indicator to gender, even when a little further along in the life cycle. The male flower is small and spade-shaped at this stage as it continues to mature. The female plant however, doesn’t develop a “flower,” but a pistil.
Fortunately for us, the developing female flower has some features that make it quite different from the developing male flower. While we said the male flower will be spade shaped, the female pistil is longer and pointier. Specifically, the pistil has a uniquely defining feature: it will look like it has a two wispy white hairs extending out from it, and these are the actual pistils themselves. If you are able to identify the flowering parts and see these white “hairs,” you can be very confident that you are looking at a female plant.
Author’s Note: If you find plants with both male and female flowering parts you’ll want to get it out of your grow. These plants are hermaphrodites and will pollinate your plants when they are mature. We will talk more about this phenomenon in a later article.
So there you have basics of Cannabis sexing. Watch for our more advanced germination articles where we will discuss leaf sample DNA testing you can do at home (really!)
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About the Author
Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network. In addition to editing the GN blog, Chris also works on the Canna Cribs series.