Spotting Male Cannabis Plants Early
The problem of male cannabis plants can be completely avoided by using feminized cannabis seeds. However, if you chose to grow out some regular seeds, it is very important to know how to identify the males fast. Male cannabis plants do not make for good smoking material, and do not contain any amount of THC of CBD of worth. So do not keep them hanging around.
Identifying Male Cannabis Plants
Unfortunately, there is no way to tell what sex your cannabis seeds will be early on. You have to wait for a plant to show its sex. This happens during the pre-flowering stage, when the plant begins to put its energy into reproduction.
If a cannabis plant is male, it will begin to develop little sacks of pollen at its nodes (the area where branches meet stem). They will look like little balls, either on their own or in clusters depending how far into the pre-flowering stage your plant is. Conversely, if a plant is female, its nodes will begin to produce immature calyxes, each with one or two white wispy pistils.
Sexing Your Cannabis Early
There are a couple of techniques you can harness in order to weed out the male cannabis plants of your crop before they properly enter the pre-flowering stage. This allows you to remove them early, and prevents you wasting time and resources on them.
The first technique is to place a light tight, black, breathable bag on a lower branch of each plant for 12 hours a day. It works by stimulating pre-flowering in that part of the plant; and as soon as you begin to see its sex, you can stop placing the bag over it, letting it revert back into its vegetative growth.
The second technique is somewhat like the first one, but instead of covering a branch of each plant, you simply switch the light cycle for the entire crop to 12/12. This will cause pre-flowering, and once you are sure of each plants sex, you can change back to a vegetative light cycle – your cannabis will revert back to its vegetative growth within 24 hours. The problem with this method is that it takes about 2 weeks to work, adding time to the overall grow.
So unless time is not an issue for you, it is most advisable to use the first technique. This allows the plant to continue its vegetative growth, whilst only a small section of it begins to flower – thus not adding an additional 2 weeks onto your grow time.
This technique works particularly well if you are proceeding to take clones from the females - that way, you can be sure to have a 100% feminized grow.
In some situations, a cannabis plant can turn hermaphrodite. This means it produces both male and female reproductive organs (both pollen sacks and calyx), so keep an eye out. This only usually happens when a cannabis plant becomes increasingly stressed, and fears for its life. Becoming hermaphrodite is a survival mechanism that, in theory, assures the ongoing survival of the plant - as it can pollinate itself.
As a hermaphrodite could potentially turn bud into seeds, make sure to remove them as soon as they are found.
Note: Hermaphrodite pollen can be used to produce feminized seeds when used correctly, but this is a very advanced technique of seed production, and is not relevant to a hobby grower trying to produce bud.