4 stages of marijuana plant growth
Cannabis plants go through a series of stages as they grow and mature, and those different growth stages call for different amounts of light, nutrients, and water.
It’s important to know these stages and how long each lasts to know what the plant needs and when. Knowing where your cannabis plants are in their life cycle will dictate when to prune, train, and trellis your plants, and when to harvest.
How long does it take to grow a marijuana plant?
Generally speaking, it takes anywhere from 10-32 weeks, or about 3-8 months, to grow a weed plant from seed. It’ll be quicker if you start with a clone or an autoflower seed.
The biggest variability in how long a marijuana plant takes to grow will happen in the vegetative stage—after the seedling phase and before flowering.
If you’re growing indoors, you can force a weed plant to flower after only a few weeks when it’s small, or after several weeks when it’s big. If you’re growing outdoors, you’re at the whim of the seasons and will have to wait until the sun starts to go down in fall for it to flower and then to harvest.
When should you grow marijuana?
If you’re growing outdoors in the Northern Hemisphere, growers usually get their seeds between February and April, and you should start your seeds by the end of April. Some growers will start their seedlings inside in a more controlled environment because seedlings are more delicate, and then put their seeds in the ground outside once they’re a little bigger. If you’re growing clones or autoflowers, you have a grace period of another month or so. Plants usually need to be outside, in the ground, by the end of June.
Harvest happens sometime between September and November. This depends on your local climate, as well as the weather that particular year—one year it could be the end of September, the next, end of October, and growers in the Pacific Northwest will have to pull down their crops earlier than those in Northern California.
If you’re growing weed indoors, you can grow whenever you like. Keep in mind that the outside environment will affect your grow space—you may need to add heaters in the winter or fans and ACs in the summer. Other than that, you can start seeds whenever you like and flip them into flower whenever you like, depending on how big you want the plants.
Important dates for growing marijuana outdoors
The Spring Equinox is a good reminder that it’s time to kick off the outdoor growing process and start germinating your seeds.
As the sun reaches up high in the sky, your cannabis will want to as well. Make sure all of your plants are outside by the Summer Solstice.
The weather will start to turn and the sun will begin descending in the sky as your plants fatten up with sweet, sticky buds. It might be tempting, but wait until around the Fall Equinox to start harvesting.
Everything should be cleaned up, dried, and curing well before the Winter Solstice. Now’s a good time to make your own cannabutter, topicals, or tinctures with all that trim from the harvest. Kick your feet up, relax, and hunker down for the cold, it’s been a long growing season!
Notes on marijuana growth phases
We can’t stress enough that the timeframes in the above graphic are ranges of time for the Northern Hemisphere. You’ll need to adjust them based on your specific region and local weather and climate.
Be sure to keep a grow journal to track the progress of your plants. Looking back on your notes will help you learn from mistakes and maximize the quality and quantity of your buds.
Take meticulous notes on when and how you perform each step, as well as what the weather is like. Other notes can include how much water you give plants, at what intervals, and how much nutrients you give them. Pictures will also give you a better sense of how your plants look along the way.
What are a weed plant’s growth stages?
The growth stages of marijuana can be broken down into four primary stages from seed to harvest:
- Germination (3-10 days)
- Seedling (2-3 weeks)
- Vegetative (3-16 weeks)
- Flowering (8-11 weeks)
Seed germination length: 3-10 days
Marijuana light cycle: 16 hours a day
The first marijuana plant stage begins with the seed. A cannabis seed should feel hard and dry, and be light- to dark-brown in color. An undeveloped seed is generally squishy and green or white in color and likely won’t germinate.
Once your seed has germinated, or sprouted, it’s ready to be placed in a growing medium, like soil. 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.
As roots develop, the stalk will rise and you’ll begin to see the first iconic fan leaves grow, at which point your cannabis plant can be considered a seedling.
Seedling stage length: 2-3 weeks
Marijuana light cycle: 16 hours a day
When your marijuana plant becomes a seedling, you’ll notice it developing more of the traditional cannabis fan leaves. As a sprout, the seed will initially produce leaves with only one ridged blade. Once new growth develops, the leaves will develop more blades (3, 5, 7, etc.). A mature cannabis plant will have between 5 or 7 blades per leaf, but some plants may have more.
Cannabis plants are considered seedlings until they begin to develop leaves with the full number of blades on new fan leaves. A healthy seedling should be a 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. Be sure to give it plenty of light.
Even if growing outdoors, a lot of growers will start their seeds inside under an artificial light to help them through this delicate stage of marijuana growth.
If you buy a clone from a grower or breeder it will be a seedling, so you can skip the seed germination phase.
Vegetative stage length: 3-16 weeks
Marijuana light cycle: indoor—16 hours a day; outdoor—at least 8 hours of direct sunlight (“full sun”), plus several hours indirect sunlight
The vegetative stage of cannabis is where the plant’s growth truly takes off. At this point, you’ve transplanted your plant into a larger pot and the roots and foliage are developing rapidly. This is also the time to begin topping or training your plants.
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 the roots will also grow outward, so start watering further away from the stalk in the soil so roots can stretch out and absorb water more efficiently.
Vegetative plants appreciate healthy soil with nutrients. Feed them with a higher level of nitrogen at this stage.
If you need to determine the sex of your plants (to discard the males), they will start showing sex organs a few weeks into the veg stage. It’s imperative to separate males so they don’t pollinate the females.
Flowering stage length: 8-11 weeks
Marijuana light cycle: 12 hours a day
The flowering stage is the final stage of growth for a cannabis plant. This is when plants start to develop resinous buds and your hard work will be realized. Most strains flower in 8-9 weeks, but some can take even longer, especially some sativas.
Outdoors, flowering occurs naturally when the plant receives less light each day as summer turns into fall. Indoor growers can trigger the flowering cycle by reducing the amount of light marijuana plants receive from 16 to 12 hours a day.
Within the flowering stage, there are three subphases:
- Flower initiation (week 1-3): The plant will continue to grow and females will develop pre-flowers—pistils, or white hairs, will grow out, which are the beginnings of buds.
- Mid-flowering (week 4-5): The plant itself will stop growing and buds will start fattening up.
- Late flowering/ripening (week 6 and on): Trichome density will increase and plants will get very sticky; keep an eye on the color of the pistils to tell when to harvest.
There are a number of changes to consider once plants go from the vegetative stage to the flowering stage:
- Don’t prune when plants are flowering stage, as it can upset their hormones
- Plants should be trellised so buds will be supported as they develop
- Consider giving plants bloom (phosphorus) nutrients
When do buds grow the most?
Buds typically grow the most toward the end of the flowering life cycle. You probably won’t notice much budding out at the beginning of the flowering stage, and it will slow down toward the end of the cycle, when buds become fully formed.
Once buds have reached full maturation, it’s time to harvest your marijuana.
Pat Goggins and Trevor Hennings contributed to this article.
Knowing where your cannabis plants are in their life cycle will dictate when to prune, train, and trellis your plants, and when to harvest. Learn more about marijuana growth stages today.
Marijuana’s History: How One Plant Spread Through the World
From the sites where prehistoric hunters and gatherers lived, to ancient China and Viking ships, cannabis has been used across the world for ages, and a new report presents the drug’s colorful history.
In the report, author Barney Warf describes how cannabis use originated thousands of years ago in Asia, and has since found its way to many regions of the world, eventually spreading to the Americas and the United States.
“For the most part, it was widely used for medicine and spiritual purposes,” during pre-modern times, said Warf, a professor of geography at the University of Kansas in Lawrence. For example, the Vikings and medieval Germans used cannabis for relieving pain during childbirth and for toothaches, he said.
“The idea that this is an evil drug is a very recent construction,” and the fact that it is illegal is a “historical anomaly,” Warf said. Marijuana has been legal in many regions of the world for most of its history.
Where did pot come from?
It is important to distinguish between the two familiar subspecies of the cannabis plant, Warf said. Cannabis sativa, known as marijuana, has psychoactive properties. The other plant is Cannabis sativa L. (The L was included in the name in honor of the botanist Carl Linnaeus.) This subspecies is known as hemp; it is a nonpsychoactive form of cannabis, and is used in manufacturing products such as oil, cloth and fuel. [11 Odd Facts About Marijuana]
A second psychoactive species of the plant, Cannabis indica, was identified by the French naturalist Jean-Baptiste Lamarck, and a third, uncommon one, Cannabis ruderalis, was named in 1924 by Russian botanist D.E. Janischevisky.
Cannabis plants are believed to have evolved on the steppes of Central Asia, specifically in the regions that are now Mongolia and southern Siberia, according to Warf. The history of cannabis use goes back as far as 12,000 years, which places the plant among humanity’s oldest cultivated crops, according to information in the book “Marihuana: The First Twelve Thousand Years” (Springer, 1980).
“It likely flourished in the nutrient-rich dump sites of prehistoric hunters and gatherers,” Warf wrote in his study.
Burned cannabis seeds have also been found in kurgan burial mounds in Siberia dating back to 3,000 B.C., and some of the tombs of noble people buried in Xinjiang region of China and Siberia around 2500 B.C. have included large quantities of mummified psychoactive marijuana.
Both hemp and psychoactive marijuana were used widely in ancient China, Warf wrote. The first record of the drug’s medicinal use dates to 4000 B.C. The herb was used, for instance, as an anesthetic during surgery, and stories say it was even used by the Chinese Emperor Shen Nung in 2737 B.C. (However, whether Shen Nung was a real or a mythical figure has been debated, as the first emperor of a unified China was born much later than the supposed Shen Nung.)
From China, coastal farmers brought pot to Korea about 2000 B.C. or earlier, according to the book “The Archeology of Korea” (Cambridge University Press, 1993). Cannabis came to the South Asian subcontinent between 2000 B.C. and 1000 B.C., when the region was invaded by the Aryans — a group that spoke an archaic Indo-European language. The drug became widely used in India, where it was celebrated as one of “five kingdoms of herbs . which release us from anxiety” in one of the ancient Sanskrit Vedic poems whose name translate into “Science of Charms.”
From Asia to Europe
Cannabis came to the Middle East between 2000 B.C. and 1400 B.C., and it was probably used there by the Scythians, a nomadic Indo-European group. The Scythians also likely carried the drug into southeast Russia and Ukraine, as they occupied both territories for years, according to Warf’s report. Germanic tribes brought the drug into Germany, and marijuana went from there to Britain during the 5th century with the Anglo-Saxon invasions. [See map of marijuana’s spread throughout the world.]
“Cannabis seeds have also been found in the remains of Viking ships dating to the mid-ninth century,” Warf wrote in the study.
Over the next centuries, cannabis migrated to various regions of the world, traveling through Africa, reaching South America in the 19th century and being carried north afterwards, eventually reaching North America.
How did marijuana get to the United States?
After this really long “trip” throughout the pre-modern and modern worlds, cannabis finally came to the United States at the beginning of the 20th century. It arrived in the southwest United States from Mexico, with immigrants fleeing that country during the Mexican Revolution of 1910-1911.
“Many early prejudices against marijuana were thinly veiled racist fears of its smokers, often promulgated by reactionary newspapers,” Warf wrote in his report. “Mexicans were frequently blamed for smoking marijuana, property crimes, seducing children and engaging in murderous sprees.”
Americans laws never recognized the difference between Cannabis sativa L. and Cannabis sativa. The plant was first outlawed in Utah in 1915, and by 1931 it was illegal in 29 states, according to the report.
In 1930, Harry Aslinger became the first commissioner of the Federal Bureau of Narcotics (FBN) and undertook multiple efforts to make marijuana illegal in all states. In 1937, the Marijuana Tax Act put cannabis under the regulation of the Drug Enforcement Agency, criminalizing possession of the plant throughout the country.
“Today, the federal government still classifies marijuana as a Schedule I controlled substance, along with heroin and LSD, indicating it has high potential for abuse and addiction, no accepted medical uses and no safe level of use,” Warf wrote.
From the Asian steppes where Cannabis sativa plants first evolved, to prehistoric hunters and gatherers, ancient China, Viking ships and finally the Americas, a new report outlines marijuana’s history.