There are many stages in the life of a plant, just as there are stages in the life of anything living. If you want to grow high-quality cannabis, it’s important to know how a plant changes during its life cycle, because each stage of growth needs different care.
Light, nutrients, and water need to be different at different times in the plant’s growth. This helps us decide when to prune and train the plants too. The different stages of growth also play a role in determining a plant’s sex and general health.
How long does it take a cannabis plant to grow?
A weed plant can take anywhere from 14 to 32 weeks, or around 4 to 8 months, from seed or clone to harvest.
Marijuana plants can grow very quickly or very slowly. If you grow them indoors, you can make them flower instantly when they’re small, or you can wait a few weeks when they’re bigger. This will depend on the size of your grow space. If you’re growing outdoors, then the fall is when you’ll be able to pick your crops. The buds will be fully developed in the last 8-11 weeks.
The full life cycle of cannabis
From seed to harvest, cannabis goes through four main stages.
- Germination/Clone Stage: 5-14 days
- Seedling Stage: 2-3 weeks
- Vegetative Stage: 3-16 weeks
- Flowering Stage: 8-11 weeks
Germination Stage (5-14 days)
Light cycle: 18+ hours of light
The seed. At this point, your cannabis plant is in a state of dormancy, waiting for water to bring it to life.
The cannabis seed reacts to water within minutes of coming into contact with it. A tiny embryo in a state of suspended animation begins to create auxin, cytokinin, and gibberellin, three growth-inducing chemicals, inside the seed shell. Both the roots and the stem have auxin in their growing tips. Restricting the growth of the lower branches, directs orderly new growth and develops the structure of the plant. Cytokinins promote cell division and lateral growth. Gibberellin controls the growth of stems and leaves. These plant compounds work together to promote germination.
Dark tan to dark brown is a sign of mature seeds.
Seeds that are light tan, green, or broken are not viable.
You can put your seed in its growing medium when it’s “popped” (showing the taproot), so it can start growing. The taproot will go down, and the seedling’s stem will grow up.
This is how it works: As the plant grows out of the seed’s shell, two rounded cotyledon leaves will grow from the stem. These first leaves are in charge of getting the plant the sunlight it needs to be healthy and strong.
Seedling stage (2-3 weeks)
Light cycle: 18 hours of light
Seedlings have cotyledons (embryonic leaves) and the first set of genuine leaves in the center.
The root continues to grow and absorb water, but it is still reliant on the nutrients contained in the embryonic seed.
A pair of embryonic leaves (cotyledons) emerge from the soon-to-be main stem. The plant senses gravity and adjusts its orientation such that the roots point below and the leaves grow upward. Plant growth follows the source of light once the initial shoot emerges from the growing media. Cotyledons open out and spread out to face the light, often with fragments of the split seed shell still attached. The cotyledons begin creating sugars right away through the process of photosynthesis.
With proper care, seedlings develop quickly. Roots spread swiftly through the fibers. The plants should be ready to be transplanted after around three weeks from this point.
Vegetative stage (3-16 weeks)
Light cycle: 18 hours of light
As the roots develop deeper into the planting medium, they continue to collect water and nutrients. They convey the water and nutrient solution to the leaves, who convert it to sugar to transport to the roots. The apical meristem, the topmost new growth, emerges from between the cotyledons, where it had been buried, and becomes more conspicuous. It’s not long before another pair of leaves, the first real pair, emerges.
The leaves have unfolded and grown to their full size within a few days, while a fresh set of leaves emerges from the expanding point. Three-bladed leaves usually make up the second pair. The next pair of blades could be five-bladed.
Branches begin to grow at the nodes, where the stem meets the leaf stalk, the short stalk that connects the leaf blade to the stem, as the plant continues to create new leaves from its apical meristem. As new branches sprout further up the stem, these branches continue to grow. The nodes of the site may then sprout additional branches lateraly
Until it gets environmental cues ( shorter light intervals ), the plant continues to grow vegetatively—that is, it grows the main stem, branches, and leaves but no flowers…. Yet!
Flowering Stage (12 hrs on, 12 hrs off)
Light cycle: 12 hours of light
Cannabis is a short-day flowering plant that blooms in the fall. It regulates its growth and flowering stages by counting the hours of darkness in order to know when to flower. Beginning with germination, the plant produces a hormone called phytochrome (Pr). The chemical Pr is converted to its inactive form, Pfr, by the red spectrum of light, which is found in both daylight and lamplight.
Pr reaches a critical level when there are long periods of darkness and no red light. There are many more hours of outdoor light than at night throughout the late spring and early summer, and Pr does not reach a critical level.
FLOWERING WEEK BY WEEK
The cannabis development pattern shifts from vegetative to blooming within three or four days of starting a daily dark phase of 10-12 hours. After that, it follows a path that culminates in bud ripening. Although some sativas require longer, most modern plants take seven to nine weeks to mature.
Week 1: The plant’s growth has slowed.
Week 2: At the nodes, the first signs of the flower appear.
Week 3: (The stretching stage) Vegetative growth continues, with the plant reaching a size of 25–50% larger than when flowering began.
Week 4: The plants’ vegetative growth has come to a stop, and they are focusing more of their efforts on flowering. As the plants begin to generate capitate trichomes, the odor becomes more pronounced.
Week 5: Flower development accelerates. The flowers thicken in spots where they have previously grown and appear in new locations along the branch’s top. As more trichomes become visible, the odor is enhanced slightly.
Week 6: In types that take longer to mature, flower growth continues. As the plants ripen, it slows down and eventually stop in a seven-week variety. Behind the stigmas, the calyx starts to swell. The seven-week variety’s aromas become stronger.
Week 7: As THC is synthesized in the glands, the calyxes of the seven-week variety grow to nearly full size. They’ll be finished by the end of the week. The trichomes become more upright, and the caps swell as the fresh resin is produced. The flowers reach their peak around the conclusion of the week. The odor is strong, and the glands glow because they’re loaded with resin. As the flowers mature, growth slows down in the eight-week type.
Week 8: By this week, the flowers should be fully mature. and reach the peak zone in the last 72 hours. After that, they will start to deteriorate if they aren’t harvested.