These tests only require a tiny amount of plant tissue (for example a small punch-out from a leaf, or a single cotyledon leaf), so it won’t hurt or slow down your seedlings to take a test sample!
Here’s another male pollen sac pre-flower that’s on a little “stem”
Variability of Cannabis Plant Sex – How to Increase Ratio of Female Plants with Regular Seeds
One last female pre-flower without a pistil yet. The long narrow shape is the only thing that gives the sex away until pistils begin to emerge
A single male pre-flower appears
Here’s a picture that shows a pistil right as it’s emerging from the calyx!
For those who don’t use feminized seeds, being able to tell the sex of a cannabis seed by looking at it would be a pretty handy skill. But is it possible?
Think about it. Why would breeders across the globe go to all the effort required to produce feminized cannabis seeds if they could simply look at regular cannabis seeds and categorize them? It isn’t some conspiracy or well-kept trade secret.
DETERMINING THE SEX OF YOUR CANNABIS BEFORE IT COMES A PROBLEM
If you don’t want to take the risk, then sexing your cannabis early is pretty easy, and stress-free. It basically involves placing a black bag over a small section of the plant during the vegetative stage to force pre-flowering, before allowing it to revert back. This gives you a clear idea of what sex your plants are, without undue worry, wasted time, or effort.
Even feminized seed, which have been bred to have 99.9% chance of growing female, can turn into male or hermaphrodite plants if put under a ton of stress while growing. This is very rarely a worry for feminized growers, as they don’t tend to stress out their plants to this extreme extent – but it is possible.
Normally, you would wait until your cannabis plants are done with vegetative growth, and switch them over to flowering. You then watch like a hawk for any signs of sex, and move the males as soon as possible. This is risky, though, because if you leave it too long, you risk the chance of pollination – turning your bud into seeds. Unless you are getting into breeding yourself, this is something you probably want to avoid.