[Sticky] The Life Cycle of a Cannabis Plant
The life cycle of a cannabis plant can be broken down into different stages. Whether you're growing cannabis indoors, or outdoors, the plant will still go through these stages throughout its life cycle.
It is a good idea for you to research how a cannabis plant grows, before you start your first grow. To have an understanding of a cannabis plants life cycle, will give you a head start in your grow.
In this article, we will cover, each part of the cannabis plants life cycle, so you can know what to expect, as your grow progresses.
If you have any questions about a cannabis plants life cycle, feel free to ask for help in our cannabis growers forum
- Life Cycle Indoors vs Outdoors
- Cannabis Seeds
- Pre Flower
- Harvest Time
A Cannabis Plants Life Cycle
Outdoors, in its natural habitat, a cannabis plant will begin growing in spring, flower in later summer, and finish in Autumn/ Fall.
As the plant reaches its final stages, female plants would have been pollinated by males, and seeds would have been created. The plant will die over winter, and the seeds are preserved and protected in the flowers.
When spring time arrives, these seeds will detect the warmth and moisture from the early spring sun, and begin to germinate. This process repeats every year.
Life Cycle Indoors vs Outdoors
When growing outdoors, a cannabis plant will detect the changes in the length of day and night, which triggers hormones in the plant to start certain stages of growth.
Outdoors, a cannabis plant will veg during spring time, when the days are long. This is simulated indoors, with a light cycle of 18/6 ( 18 hours light, 12 hours darkness)
As the days get shorter, and nights get longer, the plant will flower. This is simulated indoors with 12/12 ( 12 hours light, 12 hours darkness)
A cannabis plant will go through these stages of its life cycle, as quickly as 12 weeks, and anything up to a year, sometimes even longer. Whether you're growing indoors or outdoors, the cycle stays the same, only the amount of time it takes changes.
Like most plants, the life cycle of cannabis plant begins with seed. There are techniques where you can grow plants from cuttings, but that is for another post. All cannabis plants begin from seed.
There are many different types of cannabis seeds, that have different genetic traits, and different uses to a grower. In its natural environment, a female cannabis plant will be pollinated by a male, and produce "regular seeds".
Regular seeds are cannabis seeds that are produced naturally by a female cannabis plant. A male cannabis plant, will disperse its pollen into the air, which is carried by the wind, or pollinating insects, onto a female.
The female cannabis plant will use male pollen to produce seeds. So these seeds, have 2 parents, one male, and one female. This means they will have a 50/50 chance of being male, or female.
As most growers want to grow cannabis to use for recreational or medical purposes, they want to grow buds, with no seeds. Because of this, male plants are not desired around the grow room. Not only will they not produce buds, but they will pollinate the females, which will then be full of seeds.
If growing with regular seeds, you will need to grow more plants than you need, as there is a good chance half of them will be male. You will also need to flower the plants early to determine sex.
To save time, space, and nutrients, many growers will now only grow "Feminised Seeds".
Male cannabis plants are not very useful to the regular cannabis user. So most Percy Growers will only grow seeds that are guaranteed to be female.
Like a regular seed, a feminised cannabis seed has two parents, the difference here is that both of them are genetically female.
Two ideal female plants will be selected from a breeders line up. These plants will display certain characteristics that are appealing to the grower. Such as big buds, lots of crystals, or mould and bug resistance. One of these plants will be treated with colloidal silver.
Making Feminised Seeds
By treating a female plant with colloidal silver, you force it to grow male reproductive parts.
The plants stays genetically female, but produces pollen. This is used to pollinate another female, giving you seeds, with 2 female parents, making feminised seeds
Feminised cannabis seeds are guaranteed to be over 99% female, with a rare occasion of hermaphrodite.
If you choose a good breeder when you choose your seeds, you will not have to worry about weak genetics, so it is unlikely you will get a male or hermie.
Autoflowering Cannabis Seeds
Auto flowering cannabis plants also come in a feminised, and regular seed variety. The difference with auto flowering strains is in the name, they will flower automatically.
This means even under a light cycle of 24 hours light, with no dark period every day, the plant will still grow flowers. Most auto growers will only grow feminised autos, and males are only used amongst breeders.
For a full guide on cannabis seeds, and how each different type works, you can see our post here:
Only regular cannabis seeds occur naturally in the wild. These seeds are the beginning of the life cycle of a cannabis plant. They hold all the genetic information, and will tell the plant how to grow. All you need to do to get it started it add some water, and keep it warm.
Germination of cannabis seed will happen over just a few days. When the seeds is in the ideal conditions, it will crack open, and a "tap root" will protrude from it.
Outdoors, in its natural environment, this will happen around early spring, as the ground becomes moist, and warmth begins to come back as the seasons change.
Germinating, Week 1
When you start a cannabis grow indoors, you need to simulate the outdoor environment by providing the seeds with high humidity, and a warm dark place. Most growers will germinate their seeds in with what's known as the "Paper Towel Method":
Cannabis is a variety of plant that will germinate very quickly. Within a week after first contact with water, 95% of seeds will be above ground and into the seedling stage if kept under the right conditions.
Seedling Stage, Week 1 and 2
When the shoot first appears from the surface of the medium, you will see it does not have the usual shaped cannabis leaves. It has 2 small, rounded leaves, these are called cataloydons.
During this stage of growth, you will be trying to imitate the spring time environment. High humidity is prefer by young plants and seedlings.
For the first week of growth, you may want to use a dome, or propagator over your plants, to keep humidity levels high
Just like germination, this stage will be over within a week to ten days, and you quickly move into early veg.
A cannabis plant will start to grow outdoors in early spring, anything from mid March to late may, depending on local environmental conditions. During the spring time and early summer, the plant will grow leaves, stems and branches. It will also spend a lot of energy building a good root base. This is known as vegetation.
Early Veg, Weeks 2-4
For the first few weeks of growth, you may not see a lot happening above the ground. Some strains will grow quickly, some will not. A lot of energy is being put into building a good root structure.
After a week or so, when the plant is stable and able to absorb plenty of nutrients, it will grow very quickly.
If you're growing indoors, it won't be long before you will need to transplant into a bigger pot, and begin some training, and topping.
Early veg will only last a couple of weeks, as soon as a good root structure is formed, the plant is stable and very resilient. The growth rate will increase and with in four to five weeks after germination, your will be into late veg.
Late Veg and Sexual Maturity, Weeks 4-5+
A cannabis plant when grown from seed needs between 4-6 weeks to reach maturity. Even if you tried to flower it from week 1, it would not start to flower until week 4 or 5.
The vegetative stage of a cannabis plant life cycle will be anything between 4 and 6 months when grown outdoors, from early spring, until late summer. This can produce huge plants.
When growing cannabis indoors, the vegetative stage can be extended for many months, and in some cases years (Mother Plants).
Vegetative Light Cycles
As long as the cannabis plant receives more than 16 hours of light per day, it will stay in veg*.
This can be used to keep a " Mother Plant" alive and vegging for years.
* Only applies to photoperiod cannabis plants
When the seasons change, and the plant begins to receive more dark hours, the flowering cycle will begin. But before the plant is ready to grow big flowers, it needs to prepare itself.
Pre Flower, Week 1 and 2 After Flip
As the days get shorter, the plants will start producing a hormone to trigger the flowering process. During the next couple of weeks, the plant will show a massive burst in growth.
Indica dominant strains can grow twice their size in just a couple of weeks. Sativa dominant strains can even triple their size during the stretch!
Before a cannabis plant is ready for flowers, it needs to stretch out, and build some stronger branches. The taller it can grow here, the better chance it will have of catching pollen in the wild.
It is best to try and reduce the stretch a much as possible when growing indoors. This will not only reduce the amount of space taken up by a plant, but will also keep internodal spacing tighter, for bigger buds.
As the plant is still building lots of stems, leaves and branches at this stage, its demand for nitrogen is high. As the growth rate slows down, so will the plants need for nitrogen.
With the end of the stretching stage, come the start of the flowering stage. This means you the plant will need different nutrients to grow properly.
The stretch will begin to finish, when you first start to see signs of flowers forming. This is known as "True Flower", and is when the flowering stage actually begins.
The flowering stage of the life cycle of a cannabis plant, is always eagerly anticipated. This is when the plant will grow buds, and that's what we are here to grow.
True Flower, Week 2-3 After Flip
Some growers will count the flowering phase from the day they "flipped". This means when the light cycle has been changed to induce flowering ( 12/12)
When the light cycle changes, a cannabis plant will spend time producing a hormone to stimulate the flowering process. It takes time for this hormones to build up, and a plant will not actually be in flower until a few days after the light cycle has changed.
True flower is the best guide on when flowering has begun. It is at this point you can tell if a plant is male or female, and the flowers begin to form.
Flower Formation and Sexing, Week one of True Flower
As true flower begins you will see the formation of reproductive organs. This is a sure sign that the flowering process has started. It is at this point in the life cycle of a cannabis plant that they begin to show signs of sex.
Even if you are growing with feminized seeds, you should have a check around the plant to ensure they are female.
Most growers would remove the males from the grow room at this stage. Only female are wanted unless you are breeding.
The plants will now spend a lot of energy building flowers. This takes up a lot more potassium and phosphorus. Many growers would start using a PK booster at this stage, to give the plant the energy and nutrients it needs to build strong flowers.
The flowering process will continue for anything from 6- 14 weeks, depending on which strain your growing. Indica dominant strains will flower quicker, than sativa strains.
As the plant comes to the end of its life cycle the THC and cannabinoids will begin to mature. This will happen towards the end of Autumn when growing outdoors.
As the terpenes mature, a cannabis plant will start to smell real strong. The pistols will begin to change to a brown, orange or red colour. This will depend on your strain.
The final couple of weeks of a cannabis plants life cycle are important to the production of THC resins and terpenes. They are important weeks, the plant might look like it is ready for harvest, but it isnt. It needs a little longer to ripen.
When the plant is ripe, there isn't much more growth to be done. All that really happens from here, is the degradation of the Trichomes.
The longer you leave your plant past its ripening stage, the higher chance you have of getting rot, mould, and even hermaphrodites. It is important you know what to look out for when your plant is coming to the end of its life cycle.
For cannabis plants grown outdoors, harvest time can range from late September, to early November. This will depend on local climate.
Outdoor growers need to be prepared for the bad weather that may come with autumn. Bud rot and mould can easily take hold of a crop if the conditions are right. Because of this, outdoor growers will harvest before the damp cold weather sets in.
For indoor growers, plants can be pushed a little further, as you don't have to worry so much about damp and mould. You can leave your plant until it is ready to be harvested, depending on your preferences.
When to Harvest a Cannabis Plant
For outdoor growers, the end of the life cycle of a cannabis plant will come as cold weather sets in at the end of Autumn/ Fall.
For indoor growers, the trichomes are checked for levels of maturity, and the cannabis will be harvested at the preferred level of potency.
When the plant is ready, it is harvested, and hung upside down, until dry.
A wild cannabis plant at this stage would have been pollinated and full of seeds. These seeds fall to the ground, and will start to grow again next spring time, when the whole process begins again
Final Notes on The Life Cycle Of a Cannabis Plant
After harvesting a cannabis plant, there are many ways for you to continue with that grow. You can take cuttings from the plant, and then "reveg" them. You can revert the lights back to 18/6, and reveg the whole plant. Within a few weeks, new growth will start, and you can carry on your grow with a plant that already has a root ball.
Cannabis is an amazing plant, and growing it is an amazing hobby. It is resilient, hardy, and can take a lot of stress. It really is a great plant for anyone to grow. Why not get started?
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