Like most plants, the cannabis plant has 5 stages to its life cycle. The cannabis plant is an annual plant, which means it will complete all of these stages in one growing season and will not survive to the following year. The lifespan of a cannabis plant is about 4-8 months, depending on the strain and method of cultivation; for example, growing a plant from a clone will bring it to maturity faster than growing it from a seed. Cannabis is a strong and hardy plant and can be grown in most growth mediums. Also like other plants, cannabis needs 3 main things to survive: light, water, and nutrients. We’ll go into more detail with these later too.
1st stage: germination
The first week or so of the plant’s life is called germination. This begins when a mature seed is placed into a damp, fertile environment and exposed to light. At first, only one single root will grow down, and only one single stem will grow up. This root is called a taproot, and all plants grown from seeds will have one. The stem will continue to grow and will eventually sprout its first leaf, called a cotyledon (KAH-tul-E-dun). Once it has a leaf, it can start making its own energy by absorbing sunlight! This process is called photosynthesis. From there roots will shoot off of the taproot, and then the first true leaves will appear. Once that happens, we are ready to move on to the next stage of growth.
2nd stage: Seedling
For the next two weeks, the plant will be a seedling. This is the stage in the plant’s life where it is most vulnerable to disease and pests, so growers need to take extra special care and make sure that their plants stay healthy and happy. The correct amount of relative humidity (RH) is very important for this: too dry, and the plants can dehydrate and not grow; too humid, and they are more vulnerable to mold and other fungi, as well as insects and other pests that can ruin a crop. The other thing to keep in mind is the right amount of sunlight (or artificial light). Since this part of the plant’s life is usually in the spring or early summer, the seedlings like lots of light, usually between 18 and 24 hours a day.
The seedling will also start to grow finger leaves. These are the leaves that we are all familiar with, but at first they are tiny and will only have three “fingers”. They grow off of the stem in pairs opposite each other, almost like two hands getting ready to high five over the plant’s head! Eventually, leaves with five fingers will sprout – once that happens, the plant is considered mature. Healthy seedlings should have a sturdy stalk and a strong green color.
Since the seedlings are so sensitive, it is easy to overwater. It’s very important that they don’t rest in standing water – just like too much humidity, this is a breeding ground for mold, mildew, and other organisms that your cannabis doesn’t like.
3rd Stage: Vegetative Growth
This is the stage where the plant is focused on growing strong roots and a thick, sturdy stalk to hold all of its leaves and buds. They’ll typically be in this phase for at least two weeks, but they can be held in vegetative state for a long time before moving on to flower. They still need 18-24 hours of sunlight to imitate daylight patterns of peak/late summer. They start to get a lot more hungry and thirsty here to feed all that growth, so you’ll notice that they need a lot more water. Since they’ll be getting so big, you’re going to want to make sure that they’re in bigger pots by now.
It’s at this point that the plants will start to show their sex characteristics. The cannabis plant is unusual in that it’s an annual plant that has separate male and female specimens. The highest load of psychoactive chemicals comes from unfertilized females, so making sure there are no male plants is critical. If the males fertilize the females with their pollen, the females will be too busy producing seeds and fruit to produce the desired amount of cannabinoids.
4th Stage: Flowering
This is where the plant will produce the buds which will eventually be harvested. This phase can last from 6-9 weeks and is triggered by reducing the amount of light the plants get to 10-12 hours a day, since in the wild this will happen in early fall. About two weeks after the light change, the buds will start to grow for a period of up to 5 weeks. You will then see little white hairs called trichomes start to grow on the buds (and sometimes on the leaves, depending on the strain). These hairs are so small that they actually look like little sugar crystals and they contain the highest concentration of cannabinoids, the good stuff that we’re looking for. Because they’re a last-ditch effort by the plant to capture pollen for fertilization and reproduction, they are coated in very sticky resin. This is the “sticky” that you might hear people talk about sometimes when discussing cannabis. Once these trichomes start to turn a reddish-orange hue, then we know it’s time to harvest.
5th Stage: Harvest
Once the plant is cut down there are many different approaches to how one processes the buds, but they all have to lead to drying. Some people hang the plants to let the buds dry on the stalk; others remove buds from the stalk and place them on racks to dry. No matter what you choose to do, you want your bud to dry in a totally dark room with RH around 45%. It is very important to keep the RH stable, as it can dramatically affect the quality of the final product: too much moisture in the air can open the door for mold, mildew, and other fungi; while too little means the bud will dry too quickly, giving it a harsher smoke and an undesirable taste.
Some growers also like to cure their bud by placing it in an airtight container for a few weeks, claiming that it can improve the flavor and decrease the harshness of the smoke. The container must be “burped” every so often to keep air circulating. Not all growers cure their bud, so if you want to it’s totally up to you.
After all this is done, most industrial cannabis will be treated one of two ways: the smokable buds will be trimmed down to get rid of excess leaf that doesn’t smoke well, while the runoff from this and the rest of the harvest process is called trim and is primarily used for extraction into concentrates and edibles.