Cannabis plants, like all living things, go through a series of stages as they grow and mature. If you want to grow your own marijuana or CBD-rich hemp, it’s important to understand the changes a plant goes through during its life cycle.
Each stage of growth requires different care. Different stages require different amounts of light, nutrients and water. They also help us know when to prune and train plants. Knowing the plant’s sex will help you adjust factors to support its stages of growth, as well.
There are four primary stages from seed to harvest in a cannabis plant’s life cycle:
This stage typically lasts 5-10 days and begins with the seed. Before you plant the seed, the cannabis plant is dormant. It needs water, light (~18 hours/day), and soil to be brought to life.
“The tap root will drive down while the stem of the seedling will grow upward. Two rounded cotyledon leaves will grow out from the stem as the plant unfolds from the protective casing of the seed. These initial leaves are responsible for taking in sunlight needed for the plant to become healthy and stable.”
When the first iconic fan leaves grow, that’s when the plant can be considered a seedling.
This stage typically lasts between 2-3 weeks. The light cycle is typically 18 hours/day.
As the seedling grows, you’ll notice that it develops even more traditional cannabis leaves. New growth will result in more blades. A seedling has only one ridged blade but a mature cannabis plant will have between 5-7 blades per leaf. Some may have even more.
Once the seedling develops leaves with the full number of blades on new fan leaves, it moves into the vegetative phase. A healthy seedling should be vibrant green in color.
Note: During this stage, it can be easy to overwater the plant. Keep this in mind to prevent the plant from developing disease or mold.
This stage typically lasts between 3-16 weeks. The light cycle remains at 18 hours/day.
Once your plant reaches this stage, expect some major growth. Hopefully, you’ve transplanted your plant into a larger pot. This will allow the roots and foliage to develop rapidly. As Leafly notes, this is also the time to begin topping or training your plants (more to come on these topics).
Determine the space between the nodes to figure out what type of cannabis you are growing. Indica plants tend to be short and dense whereas sativa plants grow lanky and more open in foliage.
At this stage, you will need to increase your watering. When it’s young, water the plant closer to the stalk. As it grows, the roots will also grow outward. To accommodate the plant, start watering further away from the stalk so the roots can stretch out and absorb more water.
This stage typically lasts between 8-11 weeks. The light cycle reduces to 12 hours/day.
The final stage of a plant’s life is the flowering stage. Flowering occurs naturally when the plant receives less than 12 hours of light a day. Expect resinous buds as a result of your hard work.
The plants should start showing their sex organs a couple of weeks into the flowering stage. It is incredibly important to separate the males so they do not pollenate the flowering males.
There are a couple of factors to consider when growing cannabis:
- Your plants should not be pruned after three weeks into the flowering stage. Why? Because it can upset the hormones of the plant
- Plants should be trellised so that buds are supported as they develop (more information to come)