If you click the following picture and zoom in close, you can see pollen sacs scattered among the leaves
Cannabis pre-flowers appear at the base of leaves when male plants are about 3-4 weeks old, and female plants are 4-6 weeks old.
Super close-up picture of a female cannabis pre-flower
A single male pre-flower appears
Just like the above male plant, sometimes you get almost what looks like two tiny little leaves that the pre-flower pollen sac “unfurls” from. In the above picture the pollen sac is still mostly hidden, while in this next picture, the tiny growths have opened up to fully reveal the pollen sac. This can be confusing because these extra growths don’t appear on all plants, and are not a pre-flower or a stipule.
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
Although testing can be done as early as week 1 from germination, waiting until week 3 to conduct testing on seedlings can increase accuracy, and some companies won’t conduct testing until week 3.
This pre-flower doesn’t have a pistil sticking out at first, but the shape helps tell you it’s a female plant. If you’re not sure about sex after spotting a pre-flower, it’s a good idea to wait and see for a little while, just to see if a white hair appears (which means it’s definitely a girl)
Male pre-flowers tend to have a “spade” shape, like the spades from a deck of playing cards. Male cannabis plants often (but not always) reveal their sex sooner than female plants.
Learn how to find tiny pre-flowers at the base of each leaf to determine the sex of your plant in the vegetative stage (at only 3-6 weeks from germination)!