Sexing your plants

Cannabis plants are dioecious which means they have two separate sexes – male and female, which is pretty rare in nature. To produce seeds and future offspring, which is the ultimate goal for any plant, you’ll need cannabis plants of both sexes. Male plants pollinate the female plants which then produce seeds for the next generation.

Growers usually want just female plants because they produce buds with more potency and higher cannabinoid and terpene percentages, while male plants are used, primarily for breeding and genetic purposes.

During vegetative growth there’s no reliable way to easily determine what sex cannabis plant is. Usually male plants grow more aggressively and faster than female plants but that isn’t always the case because of the different phenotypes that may ocurre under the same strain.

Unless you’re using feminized seeds, there’s no way to determine if your plant is male or a female but to put them to flower and even then, you’re going to have a male plant here and there, so it’s important to stay vigilant and at the top of your game.

Identifying the sex of your cannabis plants

You can now have your plants and even seeds lab tested to determine their sex. A lot of labs offer sexing as soon as your plant is a week or two old. You send them a cut or a sample of your plant, they look for the Y chromosome and if found, it means that your plant will be male. Determining chemotype and high CBD is also available with most of the tests.

Without a lab, to determine the sex of your plants, you need to put them to flower. There are a few different methods each having it’s pros and cons. Besides waiting for flowering phase and then identifying the males you can take a clone from your plant and put it in flower, because the clone is the exact genetic copy of the mother, clone will be the same sex as the mother plant.

You can start your plants on 12/12 light cycle or switch them in any time, which will immediately force them to start flowering and then revert them back to vegetation but that method is much more stressful and can cause various hormonal issues and problems – most notably hermaphroditism, causing your plants to have both male and female flowers.

Just before the plants start to develop their flowers, they would go through a phase called pre-flowering,usually 7-10 days after switching the light cycle, in which plants will show their “preflowers”. Preflowers will be located on the parts where branches join the stalks – female look like two, usually white, tiny hairs – called stigmatas, coming from a rounded, pear or tear shaped bag while male look more like ‘regular’ flowers, with round, usually bigger bags without any hairs. As they mature, preflowers will form flowers and identifying the plants will be even more easier.

Male cannabis plants

As male plants mature and start to go into full flower, preflowers will be replaced by real, male flowers. Male flowers don’t form buds, but rather grow flowers that have petals, sepals and calyx and later develop pollen sacks that form grape or bell like clusters. When pollen sacs reach maturity they open and male pollen is released, pollinating any female plants that may be in the vicinity. Pollen sacs will open much sooner than the plant itself will mature so removing the males in time is very important.

So, unless you want seeds, you need to removing male plants from the females in your grow before the pollen sacs open. Male plants contain THC, CBD and other cannabinoids and terpens as well, just not in the same amounts like the female plants so breeders tent to capture the pollen, which they keep for future breeding projects and letting the male plants finish too, to see which would be best suitable for crossing. Sugar leaves and the rest can be used for concentrations, juicing and other products.

Female cannabis plants

Female plants will usually start with the flowering later than the male plants. Preflowers should usually appear within 7-10 days and real flowers but should start appearing 10-15 days from switching the light cycle. As female plants mature they will start to develop stocked clusters which are know as buds. First tiny, usually white hairs will start to show up, then they will start fattening up and gaining on volume forming bigger and denser buds. As the flowers and the plant come to peak maturity, the pistils will change their colors, in most cases to brown or orange, signaling that the flowering has come to an end.

Depending on the strain and the phenotype, it will take a couple of weeks for the flowering to finish. Usually Indica strains take less to finish, about 7-10 weeks while Sativas take their time and can finish in twice the time, usually from 10-15 weeks.

Hermaphrodite plants

Sometimes genetic but most times stress induced, cannabis plants can sometimes be hermaphrodites – which means that they are both male and female sexes and show characteristics of both.

Unstable genetics or heavy stress of any kind, in most cases light stress, can make your plants be affected by hermaphroditism. The plant will start by showing one sex first, then along side flowers of one sex, the opposite sex flowers will appear too.

Hermaphrodite plants don’t have that much pollen sacks as male plants do, so the area they would affect if their pollen sacks would to open, would be much smaller but still, it’s wise to move them away from your female plants in order for them not to get pollinated and start producing seeds.

Although hermaphrodites might not be the best sight in the grow room, they still have their uses – just as males, they have THC, CBD and the rest of the cannabinoids and terpenes and can be juiced, made into concentrates and if you don’t mind picking out the seeds, even smoked.

Also, hermaphrodite plants that were originally female will produce only feminized seeds, so it might come in handy but, obviously hermaphroditism would be in the genetics, so you’d need to stabilize that in order to get the best out of the genetics.

How to identify hermaphrodite cannabis plants?

In most cases hermaphrodite cannabis develops like a female weed plant but later in addition to the female pistils, plants also form the male reproductive organs called stamens. Unfortunately, it is almost impossible to recognize hermaphrodites at the very beginning and early stages of plant development. But later in pre-flowering period (approx. 1-2 weeks after switching the light cycle) when the plant matures and first flowers begin to appear it becomes quite simple to determine hermaphrodite signs:

  • Female plants form pistils which are very close to the stem and looks like little onions with two tiny white hairs called “stigmas”;
  • Male flowers (“stamens”) are little bags of pollen. They are of seed shape and grouped in clusters or grapes;
  • Hermaphrodite plants will have both pistils and stamens. Unwanted male flowers can be easily recognized by banana-like shape and yellowish color.

After you’ve identified sex of your plants it’s advisable to separate the females from the males and hermaphrodites. The reason for doing so is that you don’t want your female plants to get pollinated. If female plants do get pollinated, most of their energy will go into producing seeds, not cannabinoids and terpenes and you’ll end up with buds of inferior quality that are loaded with seeds.

What to do with hermaphrodite cannabis?

If the number of so called bananas in the female flowers is not very high then growers can carefully tear them off or remove them with tweezers/scissors. Be careful not to shake pollen and not to open these stamens to prevent pollen distribution. After completing the procedure, sprinkle the plant with water to sterilize pollen residue. Watch your plants for development of new bananas in future!

If the number of male flowers is rather high the best way is to say goodbye to such plants. Hermaphrodite can not only self-pollinate but can pollinate other plants as well and spoil the whole crop.

It is very important to inspect your plants regularly, especially in the beginning of the flowering period. The earlier self-pollination occurs the more damage it will cause. As for “bananas” formed in the late stages of flowering they are much safer because even after pollination at the late stage mature buds simply will not have time to form seeds.

How to avoid hermaphrodite plants?

There are a lot of factors that may cause hermaphroditism. This phenomenon is usually a result of stress or unstable genetics. Most common mistakes leading to hermaphroditism of cannabis are:

  • Wrong light cycling (especially interruption of dark period during flowering phase)
  • Excessive humidity or excessive dryness
  • Overfeeding or lack of nutrients
  • Lack of light
  • External injury of the plant
  • Wrong temperature mode

So the best way to avoid getting hermaphrodite plants is by proper care, providing for optimal conditions and appropriate feeding and selecting good and stable genetics to start with.

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