In the world of plants, reproduction can happen in a variety of ways. Monoecious plants produce two different types of flowers on the same plant, and hermaphrodite plants grow single flowers that have both male and female reproductive organs.
Cannabis is a dioecious plant, meaning male or female reproductive organs appear on different plants.
With cannabis, females are usually isolated away from males—introducing males into a garden will result in pollination, causing females to create seeds.
This is important for a breeder to achieve new genetics, but most growers remove the males to allow females to produce seedless buds, also called sinsemilla. These are the resinous buds that appear on the store shelf; they all come from female plants.
If you are growing marijuana in a marijuana grow tent for medicinal purposes, you need to know how to identify female and male marijuana plants. Almost all growers prefer female marijuana plants because only females produce the coveted buds needed for medicinal purposes. Male plants have low potency and THC content compared to the female plants, and they are kept to mostly produce seeds.
When to determine the sex of marijuana plants?
Generally, cannabis plants start flowering when nights - dark periods - are longer, which is a sign to show their sex and start blooming. Actually, marijuana plants reach their sexual maturity between 6-8 weeks after seed germination , regardless of the photoperiod.
It is this fact what can help us to determine the sex of our marijuana plants without the need to make cuttings or change the photoperiod, what could strees our young plants.
As we mentioned before, when plants are about 2 months old - when they have 5 or 6 internodes - they are sexually mature, which is to say, they have set their sex. In some cases - most of them produced by stress - plants will show both sexes, being what we call hermaphrodites, but generally at this moment plants show their true sex, that will mantain for their entire life cycle.
This technique of premature detection of the sex needs a little practice, but once mastered it will allow us to determine the sex of our cannabis plants at a very early stage.
Sexing marijuana from cutting
If we can't sex our plants with this technique, we can take a cutting from each of our marijuana plants and flower it in a growing tent - 12 hours of light/darkness photoperiod - what will force it to flower and show its sex, that will be exactly the same as its mother plant.
What we don't recommend at all is forcing the flowernig of mother plants for a few days/weeks and once they show their sex placing them again with a growing photoperiod (18 hours of light/6 hours of darkness), since this will produce major hormonal changes inside the plants, being an easy way to stress them - what will improve the chances to get hermaphrodite plants.
Why Sex Cannabis Plants? The Role of Male and Female Plants
For the most part, the average home grower wants female cannabis plants. The ladies are the ones that produce the fattest, most resinous and most potent flowers – aka buds. Male cannabis plants are only desirable if someone wants to breed cannabis and save seeds (which is a whole other topic for another day). Even then, the grower will want to spot the difference between the male and female plants and separate them early on, unless they want free cross-breeding and pollination between many types of stains.
Not only are the males less desirable, but male cannabis plants interfere with the quality and production of your female plant. Males grow pollen sacks, and produce pollen. When a female cannabis plant becomes pollinated by a nearby male, her energy shifts into producing seeds.
Like most things in nature, female cannabis plants have a biological drive to reproduce. After the deed has been done, she will sit back and relax. While a pollinated female cannabis plant WILL still develop decent size buds, they are usually lower quality and contain less THC and other desirable cannabinoids. Not to mention, they’ll be full of seeds. When left un-pollinated, a female cannabis plant’s flowers (buds) will continue to swell, develop more trichomes and become increasingly resinous. She is trying to get as sticky and large as possible to catch pollen in the wind. That sweet sinsemilla – aka unfertilized, seed-free cannabis.
The characteristics of male marijuana plants
The male marijuana plant is the main producer of pollen, which the female needs in order to naturally reproduce. They’re also used in the creation of seeds, especially when the marijuana grower wants to create their own strain of cannabis. They have
Pods that release pollen with the appearance of small flowers
Thicker stalks
Fewer leaves on them
The sturdier stalk is instrumental in providing support to the male plant as it grows taller than the female. Male cannabis plants show their sex earlier than females.
The characteristics of female marijuana plants
The female marijuana plant is characterized by bulbs with translucent hairs on them occurring between nodes. They also have slimmer stalks and are much shorter in height compared to male plants. They tend to spread horizontally rather than vertically when growing. Female plants have
Fuller, broader leaves
More leaves at the top of the plant
A pistil - Not present on male plants, the pistil consists of the stigma and ovule where the stigma appears as an antenna at the top of the plant. It aids the plant in getting pollinated.
Some females can also have male parts meaning it will have both the male pods with pollen in them and the female bulbs with the translucent hairs. These are to be treated as males because they will ruin the crop.
Sex Determination of a Cannabis Plant Is One of the Most Important Things in Growing
As we said, this article is for those who grow cannabis plants from seeds they pulled from their nugs. You will also find this guide useful if you have random seeds that you know are not feminized.
The old saying goes that “there is no stigma on a female clone for plants that look like marijuana,” and this rings true even to this day.
When growing indoors, you can’t go wrong with clones if you want to avoid the male weed plant altogether. They’re a little more fragile than seedlings (mainly because they don’t produce a strong taproot). However, for efficiency and “ease-of-use,” they’re typically your best bet. As long as they’re appropriately rooted, clones are pretty hard to screw up.
Also, they make sexing cannabis – and knowing how to tell if your plant is male or female before flowering – totally irrelevant. On the downside, clones are expensive. While there’s typically a big difference in cost for recreational or medical patients (MMJ cardholders usually get a 50% price reduction or thereabouts), you can expect to pay around $20-$30 for a single plant.
Is It Worth It? In Our Opinion, Definitely.
With a clone, you get to take a lot of guesswork out of the equation. As long as your growing operation is stable, you theoretically should know the exact type of yields you’ll get. Moreover, for one individual (unless you’re Snoop Dogg), a single plant will generally provide more than enough bud for a long, long time.
We’re fully aware that the majority of weed lovers in the U.S. don’t have access to a dispensary where they can buy a clone. Fortunately, many of the best grows in the world begin from seedlings. Please note that patience is essential when trying to identify male and female plants.
It takes years and years of experience. It is worth it because knowing what to look for in the pre-flower formation is often as important as merely removing males, in terms of overall yield quality.
Final: Male vs. Female Marijuana Plants – A Quick Rundown
Female crops have pointed green calyxes that sprout a white and wispy pistil – a hair-like part of the plant that grows from the calyx.
Male crops have round, green pollen sacs that enlarge and don’t sprout a white, wispy pistil. Catch these sacs before they overfill with pollen, burst, and contaminate your crop!
In adverse situations (i.e., if the plants are stressed or hungry), portions of a crop can become hermaphroditic. This means they develop both male and female characteristics to self-pollinate and reproduce. It is not the end of the world for those that are growing for personal use because you can still produce buds. The downside is that you receive a far lower concentration of resin.
It is a potentially catastrophic situation for commercial growers, however, as hermaphrodites (or “herms,” as some people call them), are full of seeds and not sellable or desired. Just keep in mind that the male cannabis crop is not entirely useless; a fact we discuss in the next section.
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