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Early Sign of Male Cannabis Plants


If growing cannabis for flower, you must employ a strict “No boys allowed” door policy. It’s a sight you’ll no doubt dread – a male plant in amongst your girls. It would be best if you took fast action to remove it from your grow room, but you’ll have to know what to look for before doing that. If you’re a beginner grower wondering how to spot the early signs of male cannabis plants, this article is for you.

Male v Female Cannabis Plants

Cannabis plants are dioecious, meaning they can be male or female. If growing cannabis for consumption, you’re interested in female plants as they produce the cannabis flower, or buds, that people smoke. Males, on the other hand, do not produce buds. That’s not to say they’re without their uses, though. Male cannabis plants are necessary for breeding, but they have several other benefits besides.

What is a Male Cannabis Plant?

A male cannabis plant differs from a female in several key ways. Males are non-flowering, but other physical characteristics set them apart from female marijuana plants. These include:

  • Thicker main stalk and branches
  • Fewer Leaves
  • Pollen Sacs
  • Lower Concentrations of Cannabinoids (like THC, and CBD, which you can’t necessarily see but can measure) and terpenes

Since the flower is the most widely-sought after attribute of the cannabis plant, many people remove or destroy a male upon finding it in their grow area. Male plants have value to breeders, but if that’s not you, it’s important that, upon seeing the early signs of a male cannabis plant, you remove it from the proximity of the females.

Once a male starts to produce pollen sacs, it becomes capable of pollinating nearby female plants. When a female cannabis plant becomes pollinated, it shifts its energy from producing flowers to producing seeds. This means a much less productive harvest, and you’re left with a failed crop.

When Can You Tell if a Plant is Male Or Female?

Unfortunately, cannabis plants look identical through their life cycle’s seedling and vegetative stages. Admittedly, that’s not entirely ideal for sexing your plants truly early, and so you’ll have know when to become super-vigilant and carry out your checks.

The good news? Male marijuana plants tip their hand sooner than females, around a week or two sooner. Your cannabis plants will enter the pre-flowering stage toward the end of the vegetative stage. It’s at this point the males will rock up and make their presence known. In the first two to six weeks of flowering, cannabis plants typically express their gender, so this is the time to get the magnifying glass out and begin sleuthing.

How to Identify Male Cannabis Plants

Knowing the signs is key, but knowing where to look for those early signs of male cannabis plants is equally as important. Cannabis plants reveal their gender on the same part of the plant, regardless of whether they’re male or female. As early as three to four weeks after germination, males can reveal themselves. As the vegetative stage draws to a close, you should be checking the nodes of each plant – the stage where branch and main stem intersect – as it’s here where the plant’s sex organs will show.

Female vs Male:

What Happens if You Leave Males and Females Together

Female cannabis plants will begin to display small, wispy, white hairs known as pistils. Over the next few weeks, these will grow and develop into the fine cannabis buds we all prize so highly. Male cannabis plants will have a different tell, growing in the same spot. At that point between the stem and the branch, a male cannabis plant will begin sprouting tiny little pollen sacs, which are easy to identify. These pollen sacs resemble little green balls – so it should be easy to memorize what male sex organs look like on your plant!

Growing individually or in small clusters, these pollen sacs are the surest sign of a male weed plant, and as soon as you see these, you’ll want to remove them and isolate them well away from your ladies. If you have no plans to breed cannabis, destroy the males completely. Once those pollen sacs burst open, pollen takes to the air and make no mistake, it will pollinate your female plants and they too will begin seed production.

Male pollen sacs will typically open up and spread airborne pollen within four to six weeks of flowering. That pollen will attach to the stigmas of the female and pollinate her. It’s best not to leave it to chance, however, or you risk a compromised harvest.
It’s said by many that if you’re not sure, to leave it a week before rechecking the sex of your plants. However, given what’s at stake, there’s no reason to leave it a week. Check back every couple of days and look for signs of development on your plants. There’s no guarantee they will develop in unison.

Male cannabis plants typically grow taller and less bushy than females, but this alone should not be the method of determining sex. Initially, it can be hard to determine plant gender with the naked eye, so a magnifying glass or similar aid is worth investing in.

A Word About Herming

If you see signs of both pollen sacs and pistils on your plant’s nodes at the main stem, you’ve got hermaphrodite cannabis plants on your hands. Chances are this has been induced by stress. Anything from lighting issues to nutrient deficiencies can cause hermies. It can happen at any stage in the life cycle of the plant.

Fortunately, true hermaphrodites reveal their sacs early on, giving you time to remove them from the grow area.

How to Reduce the Chances of Male Cannabis Plants

If you’re buying regular marijuana seeds, there’s about a 50/50 chance of ending up with some male plants. While regular seeds are fine for breeding projects, it’s not ideal if you’re trying to grow marijuana for consumption. The best way to reduce your chances of finding male plants in your garden is to make sure you only buy feminized cannabis seeds and only buy from a trusted seed bank dealing in quality genetics, such as Seedsman. That way, your chances of producing Sinsemilla (seedless) cannabis increase significantly.

Cultivation information, and media is given for those of our clients who live in countries where cannabis cultivation is decriminalised or legal, or to those that operate within a licensed model. We encourage all readers to be aware of their local laws and to ensure they do not break them.

Duncan Mathers