Cannabis Plant Gender
Not all medical cannabis growers will have access to feminized seeds and regular seeds are more genetically stable and far better to use for serious cultivation and mother plants to take cuttings from. Cannabis grown from regular seed will produce a 50% mix of both male and female plants so it is important that medical growers can identify the cannabis plant gender..
It is only the female cannabis plant gender that produces buds, and these contain the cannabinoids needed for medicinal use. Male plants contain insignificant amounts of cannabinoids, and release pollen that fertilizes the females, which is undesirable unless you wish to breed, so growers need to be able to identify the males so they can remove them from the crop.
The sex of your cannabis plant gender can only be identified once flowering has been induced, and there are various methods you can use to identify your plants, but the best is to flower a test cutting from each plant, as this is the least stressful.
Some growers like to change the light regime of the test cuttings from 18/6 to 36 hours of continuous darkness, and then change it to 12/12. The males should start showing in 3 to 5 days, the females a few days later, but some strains respond better than others. You should only use this technique for sexing cuttings as prolonged periods of darkness can promote the formation of hermaphrodite plants.
Seedlings can be forced into flower as soon as they reach 8cm (3 inch) tall by placing them into a box or darkened area for 12-hours each day. After 2 weeks they should have shown signs of gender, but even if they have not; remove them from the cycle and place them back into the vegetative cycle. Allow them to continue to grow on as if they have survived the winter, they will quickly develop pre-flowers (see below) and these can then be identified.
This technique does slow down the plant growth rate and can badly stretch seedlings but is useful if you have a large number of seedlings you wish to identify the gender of before planting outdoors.
Another alternative is to selectively cover a lower branch on each plant you wish to identify the cannabis plant gender. This is done by making a lightproof sleeve from black sugar paper, or a lightproof paper bag, which is then placed over the chosen branch and held on with twist ties to simulate the 12-hour daylight cycle. Don’t us plastic as this can cause mould to develop. After 2 weeks the branch will have flowered, and you can then permanently remove the cover.
Females cannabis plants
(1) Stipules (spurs) appear on both sexes and are not signs of flowering
(2) Pistil is the name of the female, white and hair like, pollen-catching structures
(3) Calyx is the body of individual flowers; thousands make up a single bud
Male cannabis plants
When the main flowers first appear they are also undifferentiated but soon the male flowers are recognized by their curved claw shape, followed by the appearance of round, pointed flower buds with five segments. In male flowers, five petals approximately 5 millimeters (3/16 inch) in length make up the calyx and may be yellow, white, or green in color.
Male petals hang down, and five stamens approximately 5mm (3/16 inch) in length emerge, consisting of slender anthers (pollen sacs), which split upward from the tip and suspended on thin filaments (1).
The exterior surface of the male calyx is covered with non-glandular trichomes.
The tiny pollen grains (25 to 30 microns in diameter) are almost round in shape when viewed under a microscope and appear slightly yellow when collected. .Male plants do not produce pistils.
Pre-flowers (primordia) are located differently to the actual bud sites but can still be a good way of determining gender in advance of the main flower formation, use a magnifying glass or loupe to make a positive identification.
The undifferentiated pre-flowers appear along the main stem at the nodes (intersections) and behind the leaf spurs (stipule).
Look for general trends in shape and the appearance of two white pistils to indicate a female; who often show one to two weeks before male pre-flowers, despite the main male flowers appearing before the female.
The female calyxes will swell and they are easier to distinguish at a younger age than males.
The first female calyxes tend to lack paired pistils, however, they soon appear in abundance. As soon as you see tiny white hairs appear you can confirm your plant is female.