Cannabis sexing – Identify early signs of male plant

While exploring cannabis seed banks, you will notice that seeds are available in either of two forms: feminized or regular. This is because cannabis is dioecious, meaning that the plants can either be male or female, and the reproductive parts do not appear on the same plant. Consequently, as a cannabis cultivator, it is vital to identify the early signs of male plants early on, especially if you are growing them for the bud. 

Female plants are the sole source of cannabis buds, while male plants are used purely for breeding purposes. If left to grow together, the male plants produce pollen, pollinating the female ovules and producing seeds. While this may be great for breeders, cultivators looking to harvest big, healthy, THC-rich buds need to eliminate male plants from their grow room to allow the females to attain their full potential. 

This piece explores everything you need to know about cannabis sexing: how male and female cannabis plants differ, early signs of male and female plants, whether the plants should be grown together, and how to tell if your plant is a hermaphrodite or not. With this knowledge, cannabis cultivation will become an easy-to-execute task, so read on… 

What is the difference between male and female cannabis plants?

Male and female cannabis plants differ in multiple ways. As highlighted above, female plants produce bud. This explains why most growers, specifically those growing to smoke or sell the potent flowers and their by-products (concentrates, oils, etc.), prefer to grow feminized seeds (more on how they are created below). Breeders grow male and female plants to ensure the continuity of specific genetics or to create new hybrids. Besides these, male and female plants have several other differences, as highlighted in the table below; 

Male cannabis plantsFemale cannabis plants 
Have Low potency due to a lack of buds. A decent amount of cannabinoids can be found in the leaves, stems, and pollen sacs.THC, CBD, and other cannabinoids are found primarily on the buds. Low levels of cannabinoids can also be found in leaves and stems.
Male plants produce a soft fibre used in the production of delicate products, such as clothing, table cloths, and other household items.Female cannabis plants produce a tough fibre material used to make bags, canvas, and shoes. 

How are female cannabis seeds created?

Feminized cannabis seeds have been genetically altered to produce female plants with a 99.9% feminization rate. Seeds in nature don’t grow like this so we have to engineer them using a number of special methods. Here is how its done….

In the first method, feminization is achieved by spraying cannabis plants with colloidal silver (daily), a non-toxic mineral. Colloidal silver suppresses ethylene, a hormone that supports the expression of the male chromosome in cannabis plants. The plant then produces pollen with female XX chromosomes instead of XY chromosomes. The pollen is then used to pollinate female plants, resulting in feminized seeds. 

Female vs male seeds

male and female cannabis plants

It is impossible to tell the difference between male and female cannabis seeds. It is for this reason that feminized seeds have become the more popular choice for the home grower that isn’t interested in breeding. If you grow with feminized seeds, you greatly reduce the risk of having male plants ruin your crop as they are typically 99%+ guaranteed to produce female plants. However, you can never fully eliminate the risk of one or two male plants, especially when you are growing a large number of plants in one go.

Cultivators that choose to grow with regular seeds always have to be on the lookout to ensure that male plants do not get a chance to pollinate the female plants. Once this happens your female plants will begin to focus all of their attention on creating seeds instead of nice juicy bud. This is the reason why you may have found the odd seed in your bud previously, the result is usually a much less potent bud and a lower yield. So for smokers and cash croppers alike male plants our not your friend. Regular seeds have roughly a 50/50 chance of either being male or female. Growers pick them for a variety of reasons, such as:

  • To breed and create your own strain.
  • Some rare strains are only available as regular seeds.
  • They may want to grow cannabis the old-school way.
  • For the thrill and challenge, regular seeds present.
  • Affordability as regular seeds tend to cost less than feminized varieties.

Whichever seeds you choose, it is paramount to stay vigilant and identify male plants as soon as they begin to show their sex. Below is a detailed description of identifying a male or female cannabis plant and what to do when you spot the early signs of male plants. 

NB: if you are working with a cutting or clone, you are already assured of the gender of the plants as they tend to replicate the characteristics and attributes of the mother plant.

What are the early signs of male plants? 

You can determine the sex of cannabis plants by looking for preflowers where the branches meet with the stem. This usually occurs on the upper part of the plants, where there is maximum exposure to light. Preflowers appear earlier in male plants compared to female plants. This happens 3 to 4 weeks into the vegetative stage when the plant has five to six internodes. During this stage of growth, it is paramount that the plants receive a sufficient supply of Nitrogen to help with the accelerated growth rate. Once you know what you are looking for the preflowers are easy to spot with the naked eye.

See the close up shot below of the early signs of a male plant. You can see the development of tiny pollen sacks that grow around the branch off shoots. Given that these develop a few weeks prior to female preflowers and take a few weeks to actually burst it is important that you catch male plants in their early stages to prevent any pollination.

early signs of male plant pollen sacks
Male pollen sacks developing on a cannabis plant

The cannabis male plant preflowers appear as spade-like pollen sacs with a rounded bottom. These sacs appear in clusters as time goes by. The sacs are filled with pollen, which in time open up to fertilize the female flower to produce seeds. If left to develop further, the preflowers, aka staminate, take the shape of hanging bananas. One of these plants can pollinate hundreds of female cannabis plants, which is not what we want, is it? So what do you do if you have a male plant?

Cannabis sexing: What to do if you have a male plant?

The moment you spot and confirm a male plant in your prized crop, remove it immediately from the rest of the plants. When left to grow further, the pollen grains from the male plants fertilize the female flower, which causes it to shift its energy from bud production to seed production. Consequently, the quality and quantity of buds produced are significantly reduced. 

Unpollinated female plants produce healthy, resinous, and fatter buds with no seeds. These buds are often called sinsemilla or seedless and are highly sought by cannabis enthusiasts that enjoy top-tier buds. Besides pollination, male plants tend to take up valuable time and space that could otherwise be directed to female plants. By removing the male plants, you will be creating a grow space that supports healthy and potent buds.

Removing a male cannabis plant from your crop

When you spot the early signs of male plants it is vital that you remove them as soon as you possibly can. The earlier you catch a male plant the better. Ideally if you are paying close attention to your crop you will notice the signs very early on. When removing a male plant from your crop be incredibly careful, make plenty of space so that its pollen sacks don’t accidentally brush any of your female plants as you escort it from the grow room.

It only takes a tiny amount of pollen to pollinate a female cannabis plant, and even trace pollen left behind from previous grows can cause this to happen. So be extra cautious when you remove them so as not to inadvertently burst any of those pollen sacks.

What are the early signs of female plants?

Female plants take longer to reach the preflower phase, usually around 4 to 6 weeks into the vegetative stage. The preflowers look like two white-amber hairs (pistils) emerging from a pear-like green ball (calyx). Female cannabis preflowers are ovate in shape and have a pointed tip, which makes them appear stretched out compared to their male counterparts. 

Sexing autoflowers?

The majority of autoflowers are only available as feminized seeds, so their growth is usually straightforward and you wont need to watch out for the early signs of male plants ruining your crop. For regular autoflower seeds (which are quite rare), the preflowers appear 5 to 6 weeks from germination. As you may know, autos tend to grow at an accelerated speed, so acting fast is paramount in preventing pollination. Remove the male plants immediately after you see the male pollen sacs developing. 

How to tell the difference between a male and a female plant preflower

Besides inspecting the physical attributes of preflowers, there are other ways that cultivators use to determine the sex of cannabis plants. In most scenarios, female cannabis plants are shorter, with multiple fan leaves and a shorter internodal distance (the length between nodes). While male plants appear spaced out, female plants are bushy and compact. So you may be able to take an educated guess relatively early on at which plants are male and female.

However, these traits should not be used as the only determiners to sex cannabis plants. Although cannabis strains may share genetics, there may be small variations in shape and size from one plant to another regardless of sex that may cause confusion. The attributes listed above should only be used to steer you in the right direction. Alternatively, you can give the plants a few days or a week to allow the preflowers to become more apparent.

What are the early signs of a hermaphrodite plant?

A hermaphrodite plant is a plant that expresses both male and female characteristics by comprising both the male pollen sac and the female flowers. The plants are monoecious and can self-pollinate. As a rule, hermie plants are treated as male plants since they can pollinate female cannabis plants within a 5km radius. Consequently, once you spot hermies in your grow room, dispose of them accordingly. If the hermies get a chance to pollinate, the female plants produce seeds with hermaphrodite genetics. So not only do you end up compromising your yield, but you also get unusable seeds – talk of double tragedy!

What causes hermaphroditism in cannabis plants?

Several factors may cause hermaphroditism in cannabis plants, most of them being environmentally centered. When the plants are subjected to stress, such as high temperatures, nutrient deficiencies, irregular dark periods characterized by light leakages, and root rot, they are more likely to respond by turning into hermies. Additionally, subjecting the plants to high-stress techniques, especially during the flowering stage, may trigger a negative response, leading to hermaphroditism. Another significant factor is genetic tendencies, whereby the seed used has a genetic history of hermaphroditism. 

What are the different types of hermaphrodite plants?

Cannabis hermie plants come in two different types;

True hermaphrodites: the plants have male pollen sacs and female flowers located on different parts of the plants. They are rare to come by but still occur from time to time. With such plants, you need to be careful and inspect all parts of the plants to ensure you do not miss the pollen sac that may be your yield inhibitor. 

Mixed-gender plants: such cannabis plants have the male and female reproductive parts in one spot. Mixed-gender cannabis plants are more common than true hermaphrodites. Yellow male anthers that resemble hanging bananas grow out of the female buds. These anthers produce the pollen that pollinates any neighbouring female plants.

How to avoid hermaphrodite plants in your grow room

Growing healthy female cannabis plants is every cultivator’s dream. At the end of the growing season, all one looks forward to are potent, resinous, massive, juicy, and healthy buds. However, issues like hermaphroditism may hinder this from happening. As a grower, you want to ensure that you avoid hermies at all costs, and here is how to do it:

  1. Purchase seeds from a reputable seed bank. This way, you can be assured that the genetics are stable and that what is promised is what is delivered. Working with shady companies will cost you time, resources, and money. 
  2. Ensure that the grow room conditions are monitored and remain stable. Avoid temperature fluctuations and light leakages during dark periods. Additionally, regularly inspect your plants as it allows you to detect issues like nutrient deficiencies and root rot before the situation escalates.
  3. Avoid extreme training techniques that may compromise its growth and development. Before trying out any technique, consider the plant’s genetics, maturity, health, and resilience. This reduces the chances of triggering hermaphroditism. 

Take away

Now, it is much easier to distinguish between male and female cannabis plants. Whether you are a prospective cultivator or looking to sharpen your sex-identifying skills, this piece has covered everything you need to know. Photoperiod cannabis plants start to preflower during the 3rd to 6th week into the vegetative phase. Autos are usually ready within 6 weeks from seed. The preflowers can be inspected on the upper parts of the plants where the branch meets the stem. Female flowers are characterized by a pear-shaped calyx with two white-hued hairs/pistils, while male cannabis plants have spade-shaped pollen sacs. To avoid hermies, ensure you select stable genetics and avoid physical and environmental stressors.

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