Being able to tell the early signs of a male plant is key to having a reliable grow. There’s nothing worse than training a plant to perfection, only for it to turn out being a male! It is the worst feeling, definitely very discouraging.
For those who don’t know, we don’t want male plants because they don’t produce bud. They produce pollen sacs, and that’s about it. Worse than that, if they pollenate the female plants, they will stop producing buds, and the yield will have seeds. It’s no good.
So then, if you want to grow weed reliably, you need to be able to tell the early signs of a male cannabis plant. There are actually a few really good ways to tell. You might want a little magnifying glass to make it easier, as the pre-growths are quite small.
How Early Can You Sex a Cannabis Plant?
You can tell the sex of a cannabis plant from about week 3 and onward. Before that point, they are basically seedlings and don’t have any defining features that we can use as signs.
Even DNA testing is unreliable before at least the third week, so wait until then to do any kind of sex checking, be it physical or chemical.
However, it might not be until week 6 and onward until you have a really good few early signs of male plants, or female.
This is generally when vegetative plants begin to produce pre-flowers. These are little growths at the nodes of weed plants, which will eventually turn into either the calyx (bud) or pollen sac.
Difference Between Pre-Flowers
Therefore, to tell the sex of your plant before they begin flowering, it’s important to look at the pre-flowers and their characteristics. This is really the only reliable way to tell, aside from DNA testing if you want to go that route.
So once you’ve got a few preflowers on the plants, observe the shape of them, and whether or not they have any spindly, hairy, thread-like “pistils” sticking out of them.
Males will have very round pre-flowers, and no pistils sticking out of them.
Females will be kind of oval shaped on one end, and round on the other. The ovular end will have a little hook-like bend in it. In addition to that, there will be a pistil sticking out of it.
One of the things I love to look for are pistils – the defining feature of a female plant. They will start coming around at week 4-6 or so, when growing in soil. They whisp themselves out of the pre-growths, and dangle out.
They are spindly, usually quite blonde in color, and have little fibers hanging off them. They are quite interesting features, really pop out and define a female plant.
Male plants do not have pistils coming out of the pre-flowers, rather they have other signs you can look for.
Female plants have pistils as a dead giveaway, but a great early sign of a male plant is the pre-flower pollen sac. They will be round in shape, and do not have any kind of pistils sticking out.
The shape is important too. Although it’s hard to tell at first, the male pre-flower will be round, nothing coming out of it,
At around week 6-7, they will start to get kind of stacked together like bunches of grapes. This is a great way to see early signs of male plant.
Once you see them all clustered together, it’s pretty hard to miss the fact that the cannabis plant is a male. Although this is not an early sign of male plants, it is very definitive.
For early signs of male plants, the only thing is the very round, circular shape of the pre-flower, barren of pistils.
A Word on Stipules
The stipules which run down the main stems of the plant offer a slight insight into determining the sex of weed plants. Both female and male plants can have stipules which do not cross each other. However, male plants practically never have stipules which cross.
Therefore, if you see crossing stipules, it gives a great hint at the plant being a female. If you also then look at the pre-flowers, and you see the shape and pistils, this will give you really solid practical confirmation of the sex of a weed plant.
Using a Clone to Determine Sex
A smart idea to show the sex of a weed plant before flowering it is to clone a little piece, and force it to flower. Simply put it under 12/12 lights, and then watch what happens. Pretty soon you will be able to see early signs of male plant or female plant.
If you want to force it to show sex even sooner, give it a good 24 hours of no light, and then switch the clone to 12/12. This will shock the plant a little, and give it an extra push.
If you really want to go out of your way to sex a cannabis plant, this a proactive way to go about it.
Just Use Feminized Seeds!
Listen, the best way to tell if a plant is male or female, is buying feminized seeds. Not only will you know that the plant will be female, but you will also be able to get top notch genetics.
Feminized seeds are usually very high quality, and so you know that the plant will turn out an insane bud producer. There’s nothing worse than wasting your time, electricity, and nutrients on a male plant, or a female with poor genetics.
For these reasons, it’s best to just get quality feminized seeds from reputable dealers such as Dynafem, Barney’s Farm, Royal Seed Bank, Humboldt Seeds, and more.