It’s hard for some to believe, but cannabis plants reproduce sexually — meaning it takes a male and a female plant to make seeds. Sexual reproduction has many benefits, but the best reason for sexual reproduction is the genetic diversity it ensures. Cannabis seeds contain genetic material from both parents, which means offspring have a good chance of getting the best possible traits for survival. Sexual reproduction is the main reason that cannabis plants today are so potent and prolific; breeders through the ages have been able to combine the genetics of plants with bigger buds, better resin and stronger cannabinoids.
Unfortunately, there is a downside to sexual reproduction, and that is the existence of two sexes. There are male cannabis plants, and there are female cannabis plants — and knowing the differences between them is critical for any grower.
Female vs Male Cannabis Plants
Female cannabis plants are the ones most growers are desperate for because they are the only sex of cannabis plant that can grow flowers. If you have ever set foot in a Boston dispensary, you know that the flower is what contains the vast majority of the plant’s cannabinoids; the weed that gets cured and sold to consumers or else manufactured into other cannabis products like concentrates and edibles is usually the flower. Thus, female cannabis plants tend to be more valuable than male cannabis plants as they produce the treasured bud.
However, most growers don’t want to wait until the flowering stage to know that their crop consists of female plants. It can take several weeks for a plant to mature enough to produce flowers (or not), and those weeks mean an abundance of wasted resources of a drop is dominated by males. The best solution is for growers to purchase feminized seeds, which have a 99 percent chance of producing a female plant — as opposed to the 50 percent chance growers get when they buy traditional seeds.
Feminized seeds can be produced one of two ways: interrupting the light cycle and stressing out a female plant during its flowering stage or spraying female plants with a silver solution. Both methods prevent the plant from producing a particular hormone in flowering, which causes the female plant to generate flowers with pollen sacs, which typically only grow on male cannabis plants. Those pollen sacs can contain only female genetic material because they originate on a female plant, so growers can use that female pollen to fertilize female flowers and be certain to create female seeds.
Unfortunately, not all purveyors of feminized seeds are trustworthy. Some growers find that seeds they believed to be feminized produce a large number of male crops, which is a waste of time and resources. Thus, it is useful to understand the physiological differences between the two sexes.
How to Tell the Difference
Growers who don’t mind waiting for the flowering stage can relatively easily distinguish the genders. In truth, both male and female cannabis plants produce flowers, but male flowers are not the delightfully trichome-covered buds that get users high as female flowers are. Rather, male flowers look like round, hard pods, which open up to release pollen to fertilize nearby female plants.
Yet, most growers do not want to wait this long — about eight weeks — to determine the sex of their crop. Though distinguishing between male and female plants during the vegetative stage is almost impossible, there is a brief window around the six-week mark when many strains do give hints about their plants’ sex. Growers should look for pre-flowers, which are small growths that will appear in the crook between a stalk and branch. Male pre-flowers look like small, green balls, and female pre-flowers look more like pointed leaves with long, white hairs growing out of the tips. Growers should give their pre-flowers a day or two of growth, so they can be certain about a plant’s gender before determining what to do with their crop.
Aside from buying feminized seeds, growers can avoid the task of hunting out male plants by growing from clones. Clones are cannabis plants that have been reproduced asexually, by propagating a cutting into an entirely new plant. Yet, clones have their own host of issues related to genetic drift and genetic diseases — so it doesn’t hurt to grow from seeds and know how to look for male and female plants.