Cannabis is an annual plant, which means that it completes its entire life cycle in one full season of growth. In nature, a cannabis plant typically starts growing in spring and flowers in the fall. During its life cycle, the plant goes through several distinct stages, each characterized by different rates of growth, as well as different rates of stem, root, and leaf production. Below you will find a simple summary of each of these stages.
Germination is the name for the process that occurs when seeds begin to sprout. Given the right amount of moisture, warmth, and air, the seed will start to undergo several hormonal changes. These changes signal to the embryo inside the seed that it is time to expand and grow. After anywhere from 12 hours to 2 weeks, the outer shell of the seed will begin to crack and the first root emerges.
Marijuana seeds can be germinated in wet paper towels, in water, or directly in soil. If germinating outside of soil, then you want to plant the seed when you see this first root. The root will then grow downward and anchor itself. After this, two seed leaves will begin growing towards the light and pop out of the soil within a few days to a week. This is the start of the seeding stage.
The seeding stage of the cannabis plant lasts for a couple of weeks to a month. This is perhaps the most precarious time in the life cycle of the plant, as it is just beginning to form a root system, a strong stem, and its first few leaves. The seedling will continue to grow steadily until it hits the vegetative stage.
Once a few larger leaves and a good root system have developed, the seedling enters what is known as the vegetative stage. This is a stage of vigorous growth that can last pretty much as long as a grower wants it to. Depending on the strain, plants may need anywhere from 1 to 4 months in order to reach maturity, but can be kept in the vegetative state for many more months afterwards, until a desired height is reached.
While plants don’t begin to show their male or female flowers yet, certain sexual characteristics do become apparent during the vegetative stage. Males tend to be much taller than females, with thicker stems and fewer leaves. If you are growing only one strain and a few plants are standing far above the others, then you can be fairly certain that these are males.
If you don’t want to remove any plants until you know for sure that they are males, then you can wait until the pre-flowering stage. This stage begins once the light cycle has been switched to 12 hours of light and 12 hours of darkness, or late summer/early fall when growing outside.
Pre-flowering happens in the couple of weeks following this shift in the light cycle. During this time, female cannabis plants will begin to produce little white hairs between their branches and their stems, while males will begin to grow little clusters of balls which will eventually contain pollen. Plants will also go through dramatic growth spurts during this time, which is why the pre-flowering period is sometimes called the “stretch.”
The final growing stage of the cannabis plant is flowering. This stage can vary drastically in time depending on the strain. Indica strains may flower in as quickly as 6 weeks, while some sativa strains may need more than 4 months! Hybrids will fall somewhere in between.
During the flowering stage, male plants will continue to grow more male flowers, and their pollen sacks will eventually open. Female plants will put their energy into bud production. An unpollinated female will put even more energy into producing the sticky trichomes which coat its flowers in the hopes of catching more pollen. These trichomes contain the plant’s cannabinoids, which is why growers prefer to harvest unpollinated females.
A cannabis plant will not continue to grow much during the later stages of the flowering phase, and this is perfectly normal. When it is nearing the end of flowering, the white hairs on a female cannabis plant will begin to turn an orange or brown color (though colors can vary greatly depending on strain).
The trichomes will also change color, going from clear, to cloudy, to amber. Most growers prefer to cultivate when trichomes are mostly cloudy with just a small hint of amber, as this represents maximum levels of THC, making for more potent bud.