Cannabis plants, like all living things, go through a series of stages as they grow and mature. If you’re interested in cultivating cannabis, it’s especially important to understand the changes a plant undergoes during its life cycle, as each stage of growth requires different care.
Different stages call for different amounts of light, nutrients, and water. They also help us decide when to prune and train the plants. Determining a plant’s sex and overall health rely on stages of growth as well.
The life cycle of cannabis can be broken down into four primary stages from seed to harvest: germination, seedling, vegetative, and flowering.
Germinating Seeds (1-2 weeks)
The first stage of life for a cannabis plant begins with the seed. At this point, your cannabis plant is dormant, patiently waiting for water to bring it to life. You can observe the quality of the seed by its color and texture. The seed should feel hard and completely dry, and be light to dark brown in color. An undeveloped seed is generally squishy and green or white in color and will likely not germinate.
To begin growing from a seed, the next step is germination (which you can learn more about here). This stage can take anywhere between 24 hours to 7 days.
Once your tap root has appeared and your seed has popped, the cannabis plant is ready to be placed in its growing medium. The tap root will drive down while the stem of the seedling will grow upwards. Initially, two rounded cotyledon leaves will grow from the stem as the plant unfolds from the protective casing of the seed. These initial leaves are responsible for taking in the sunlight needed for the plant to become healthy and stable. As the roots develop, you will begin to see the first iconic fan leaves grow, and at this point, the cannabis plant can be considered a seedling.
Seedling Stage (2-3 weeks)
Light Cycle: 18-24 hours of sunlight
When your plant becomes a seedling, you’ll notice it developing more of the traditional cannabis leaves. As a sprout, the seed will initially produce leaves with only one ridged finger. Once new growth develops, the leaves develop more fingers (1, 3, 5, 7, etc.). A mature cannabis plant will have between 5-7 fingers per leaf, but some plants may have more.
Cannabis plants are considered seedlings until they begin to develop leaves with the full number of fingers on new fan leaves. A healthy seedling should be short with dense vegetation. The plant should not appear to be reaching for the sunlight and the leaves should be a healthy vibrant green color. Be very careful to not overwater the plant in its seedling stage; its roots are so small, it doesn’t need much water to thrive.
At this stage, the plant is vulnerable to disease and mold. Keep its environment clean and monitor excess moisture.
Vegetative Stage (2 to 8 weeks)
Light Cycle: 13-24 hours of sunlight
The vegetative stage of cannabis is where the plant’s growth truly takes off. At this point, you’ve transplanted your cannabis into a larger pot, and the roots and foliage are developing rapidly. This is also the time to begin topping or training your plants.
Spacing between the nodes should represent the type of cannabis you are growing. Indica plants tend to remain shorter and denser while sativas grow lanky and less dense in foliage.
Be mindful to increase your watering as the plant develops. When it’s young, your plant will need water close to the stalk, but as it grows bigger and roots grow outwards, start watering further away from the stalk so the root tips can absorb it more efficiently.
Vegetative plants appreciate healthy soils filled with nutrients. Feed with higher levels of nitrogen at this stage.
Once the cannabis plant approaches its flowering stage, you will be able to determine whether it’s male or female based on the pre-flower located at the nodes. Female pre-flowers have two hair-like pistils growing on buds while males produce little sacs that contain pollen. As the plant develops further into the vegetative stage, it becomes easier to determine the sex. Unless you’re breeding cannabis, it’s imperative to separate the males so they don’t pollenate the flowering females.
Flowering Stage (6-8 weeks)
Light Cycle: 12 hours of sunlight
The flowering stage is the final stage of growth for the cannabis plant. Flowering occurs naturally when the plant receives less than 12 hours of light a day as the summer days shorten (or as the light cycle indoors is reduced). It is in this stage that resinous buds develop and your hard work will be realized.
There are a number of changes to consider once your plant goes from its vegetative stage to flowering:
- First, your plants should be pruned no more than two weeks into the flowering stage as it can upset the hormones of the plant.
- Next, the plant should be staked and trellised so that the plant can support the buds as they develop.
- Finally, consider feeding with blooming nutrients, and generally refrain from increasing the amount of water given to the plants.
Once the buds have reached full maturation, it’s time to harvest.