Cannabis plants are special because they are sexually dimorphic. That means there are males that produce pollen and female plants that produce seeds and flowers. Most flowering plants are hermaphroditic, which means the flowers come with both the ability to make seeds and pollen.
Most cannabis plants only show signs of their sex in the flowering stage. Seedlings and vegetating plants look the same.
When the buds of the female cannabis plant get exposed to the pollen of the male, it will make seeds. You do not want this. Not only will they explode in your joint, they’ll actually make the bud you grow less potent. Once the plant gets pollinated, it diverts energy to making seeds instead of THC.
This is why it’s important to have only female plants and do your best to prevent them from exposure to pollen. Let’s go over female marijuana plant growth.
Start Off Right: Choose Clones or Feminized Seeds
The seedling stage and the vegetative stage of male and female plants look exactly the same. It’s only once we hit pre-flowering that we can tell them apart. This means you can end up wasting weeks or months on plants you can’t even use.
The best way to guarantee you will not get a male is to grow from a cloned successful marijuana plant. By their nature, clones have 0 genetic deviations from the plant they came from, including sex. However, clones can be hard to come by. This is because you cannot get bud from a weed plant you use for cloning.
Since seeds are easy to come by, here’s a seed to harvest guide for female cannabis plants.
Choosing The Right Seeds
Ok, so you totally can plant seeds you found in the bottom of your baggie. However, that’s not setting yourself up for success if you want a great harvest.
PRO TIP: Have at least two more seeds than plants you want to grow. Not every seed will germinate. As the cannabis plant stages progress, you can choose the healthiest one.
Feminized vs Autoflower Seeds
If you want to guarantee a female plant, you want feminized cannabis seeds. This is a term that came about in the 1990s when cultivators first figured out how to genetically engineer seeds to be 99% female.
So let’s say you’re at a website wondering “wait… are autoflower seeds feminized?” The answer is yes. Most autoflower seeds you can buy are feminized. The main difference is how many hours a day of light they need.
The marketing nomenclature around this is a little weird. This is because “feminized” was a major selling point in the 90s. When cultivators started crossing cannabis sativa with cannabis ruderalis to create strains that could grow a 24-hour light cycle, the term “autoflower” became the buzzword.
So these days, if you’re buying “feminized” seeds, you’re buying feminized photoperiod seeds. If you’re buying “autoflower” seeds, you’re buying feminized autoflower seeds. If you’re looking for regular, non-feminized, non-autoflower seeds, look in your baggie. Pretty much all seeds you can buy are feminized.
But if you’re still not sure, buy feminized seeds. They’re only slightly more challenging. They give you larger and more potent yields, and they have fewer issues with hermaphroditism. If you decide to go with autoflower that’s fine, feel free to ignore the notes about how many hours of light it needs.
Sometimes cannabis plants grow both male and female reproductive anatomies. They are called hermaphrodites, or “hermies”. This happens due to a combination of genetic and environmental factors.
Now, finding out which strains are more likely to become a hermie is actually rather difficult. Seed companies do not like that information being spread because it hurts sales. That said, here are three strains that are known for issues with hermaphroditism.
- All kush variants
- Gorilla glue
Environmental factors also can produce hermies. This is because it’s a survival instinct. If the plant gets too stressed, it develops the ability to reproduce by itself. The environmental factors that cause this can include:
- Poor humidity
- Over/underfeeding nutrients
- Bad pH in the growing medium
Also bear in mind, autoflower seeds are more likely to go hermie than feminized. This is because they’re crossed with hemp.
The Cannabis Seedling Stage
The cannabis life cycle is roughly the same in both males and females in the seedling stage. Cannabis seedlings are identical, regardless of sex. Let’s go over the germination process and the seedling growth stage.
Germinating cannabis seeds is easy. You just take your seeds and put them in a wet paper towel. They don’t need light or nutrients, but they do need water and warmth. In 1-7 days it should open up and they will be ready for their first cup.
Side note: there are other methods for cannabis seed germination. However, the germination stage is so short that advanced techniques do not make a difference.
The seedling stage lasts 2-3 weeks after germination. It’s when you see the little proto leaves that are stored in the seed. In this phase, it needs a lot of light (14-16 hours a day) and not a lot of nutrients. If you’re growing in good soil, your very young plants probably have everything they need right there.
After about three weeks, you should start to see 2-3 new sets of true leaves growing in. Now it’s time to put it in its main pot if you haven’t already because we’re now at the vegetative stage.
The Cannabis Vegetative Stage
Marijuana plants are exactly the same at the vegetative growth stage, regardless of sex. It starts once the seedling has its first few true leaves, and ends when the marijuana plant gets less than twelve hours a day of light. This is not true for autoflowers, who have their growth stages genetically encoded.
Veg growth is where leaves, stalks, and roots develop. Sativa dominant strains will get very, very tall during this period. Outdoor plants should be watered a bit further away from the trunk to encourage them to stretch their root system.
Healthy plants will need a lot more nutrients during this phase, especially nitrogen. That said, you want to gently increase your nutrients in the first parts of vegging, otherwise it can get nutrient burn or even lockout.
The Flowering Stage
This is the most exciting part of the cannabis plant life cycle. The flowering phase occurs in three parts: pre-flowering, mid-flowering, and late flowering.
At the first part of the flowering stage, differences begin to emerge between male plants and female plants.
Pre-flowering: Where Sex Starts to Show
At this point, the vegetative and flowering stages will look very similar. It occurs for the first 2-3 weeks after it gets less than 12 hours a day of light. If you’re growing indoor plants, we recommend you don’t veg too long because of the pre-flowering stage.
Even though it is in the flowering stage, you won’t see buds yet. Instead, it will double in height. You’ll still want to start it on flowering nutrients because it needs to build up that phosphorus and potassium to metabolize it and turn it into buds.
The cannabis plant begins developing the first parts of its reproductive system, so pay attention. Female cannabis plants will begin to develop pre-flowers. These look like little white hairs in a V-shape. The V is where the buds will grow. Males will start developing little pollen sacs.
If you get a male, throw a trash bag over it and chop it down. You can make hash out or butter from it, but it won’t be as strong.
This is a fun part of your plant’s growth. It’s where bud growth kicks off. You’ll start seeing more and more white hairs on your weed plants. You’ll also see those first hairs turning orange or dark brown.
Now you ramp up the flowering nutrients, but keep it on the same light cycle. Indoor growers will want to make sure there are no light leaks in the growing area– this can cause your plant to become a hermie.
Indoor growing areas also need to be very well-ventilated at this phase of cannabis growth. During mid-bloom, the plant develops terpenes which give weed its smell and taste. A healthy cannabis plant will start to stink, so you’ll need to make sure you’ve got a working carbon filter and plenty of airflow.
This is the final stage before you are ready to be harvested. You’re pretty much out of the woods in terms of the plant’s sex, but keep a close eye on the buds. You don’t want mold or pests to ruin your crop.
You’ll also want to observe the hairs on the plant, during late bloom they should be more than 50% orange. When they are 90% orange, it’s time to harvest. Harvesting too late can cause a healthy plant to go hermie. Before you harvest, flush them for at least a week. Otherwise, the nutrients will make your bud taste bad.
More about cannabis
- How To Treat A Magnesium Deficiency In Cannabis
- It’s Not O-K: Potassium Deficiency in Cannabis
- How to harvest cannabis (and use the entire plant)
- Male Weed Plant Stages: Don’t Ruin Your Crop
- How To Decarb Weed For Homemade Cannabis Products
- Loving the Ladies: Female Weed Plant Stages
- Patience is a Virtue: Curing Buds for Best Taste
- Understanding weed light cycles: Get the most from your harvest
- When to switch to flower nutrients for high cannabis yield
- How to make live resin at home, step-by-step