It’s important to determine the sex of your plant so you know to remove the males if your goal is harvesting flowers. Thankfully identifying the sex of your cannabis plant grown from a seed is a rather simple process.
The preflowers might be very small at 4 weeks, incredibly difficult to identify with the naked eye so you can use a magnifying glass to take a better look. With a magnifying glass, you can examine each of the nodes on your plant and look for the small, round sacs which indicate the plant is a male or the two bracts with the hair-like stigma in them which indicate a female. The hair-like stigma will appear after the two bracts so you might notice those first.
The male plant start to produce a pollen sac at their nodes while the female plants start to produce stigmas, which spreads out and catches the pollen. You may be familiar with the orange/ amber hairs on a cannabis nug.. Those are the stigmas!
Plants can reproduce in a few different ways.
This is when growers turn to male plants. When you introduce a male plant to a female plant, that process results in cross-pollination. Cross-pollination produces seeds. Just like with dog breeding, if you breed one species with another, it will produce a mix of the two species, such as a Golden doodle, which is a mix of a Poodle and a Golden Retriever.
There are plenty of old school genetics that have stood the test of time, and due to the marketplace during that era, were never feminized. It was from around early 2000 onwards, when the advantages of feminized seeds were becoming commercially popular. Many cultivars that existed during the last 50 years are often preserved in regular seed form, either as a first generation or as a stable IBL. Back crossing or producing a new generation of cultivar should only be done with regular seeds, especially when in-breeding.
When a Cannabis seedling has been left to grow for up to 5 weeks under 18/6, the plant will begin to exhibit very small preflowers. Typically these preflowers reveal themselves once flowering is induced, however it is possible to see which sex you have when knowing what to look for.
Advanced Phenotype Hunting
There are also commercial advantages when flowers are sold with a dedicated number such as Gelato #33, Gelato #45, KM11, or O.G #18.
Regular sexed Cannabis seeds represent a breeding line that expresses an equal balance of male and female chromosomes. Working from seed using regulars is an excellent way to grow out large selections of either male or female plants. Knowing which plants belong to which sex, how to identify them early on and understanding the life cycle of a Cannabis plant, will give you the advantage when pheno hunting for an upcoming breeding project.
Male preflowers will look like a small cluster of green, oval-shaped growth. They will be noticeable between the internodal growth and can even look like a female preflower minus the pistil. By this point there is zero need to worry about male pollen sacs and cross pollination, and after several weeks, it will be evident if you have an abundance of tiny male preflowers forming.