How long does it take to grow weed

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Marijuana is a diverse plant that requires specific skills, knowledge, and conditions to grow. The one-size-fits-all approach is not applicable, especially since the cannabis plants have been crossbred and genetically modified to cater to the different needs of consumers, breeders, and cultivators. If you plan to cultivate cannabis, you may be wondering how long does marijuana take to grow, what conditions are ideal for the different growth stages, and the level of difficulty it presents.

Well, worry no more. This piece comprehensively covers everything you need to know about the various stages of marijuana growth. First, let us answer the burning question: how long does it take to grow weed? The simple answer is 9 to 32 weeks. The time variation can be attributed to two factors, which determine how long the cannabis plant will be grown for, and these are;

The genetics of the seeds – are you growing a Sativa, Indica, or Hybrid? Are the seeds autoflowers or photoperiodic?

Indoors or outdoors? – The environment in which cannabis is grown determines how long it will take to grow. For example, in an indoor setup, you can grow the plant for as long as you like since you control the environment, including the light cycles. You can easily manipulate the conditions to shorten or prolong the growth cycle. You can do little when cultivating outdoors as the plant’s growth is determined by nature. The plants will take an average of 6 months to fully mature when grown outdoors.

Type Of Cannabis Strain (Grown Indoors)Average Time To Grow From Seed
Autoflowering Indica8 – 12 weeks
Autoflowering Sativa12 – 14 weeks
Feminized Indica (photoperiod)14 – 20 weeks
Feminized Sativa (photoperiod)24 – 32 weeks
Fast Flowering Feminized (photoperiod)12 -18 weeks

Cannabis growth stages

Four significant growth stages characterize the marijuana plant’s life cycle;

  1. The germination stage lasts 2 to 10 days
  2. The seedling stage goes for 2 to 3 weeks
  3. The vegetative phase lasts for 1 to 15 weeks
  4. The flowering stage goes for 7 to 14 weeks
  5. The harvesting stages, this consists of trimming, drying and curing.

For each stage, the plant requires specific conditions and supplements to flourish. When subjected to optimum conditions, your cannabis plant will produce a bountiful harvest, making you the envy of your peers. The factors highlighted below are essential during the entire duration your plant is growing;

Light: cannabis plants (excluding autoflowers) are photoperiodic/photosensitive, meaning that they depend on light exposure and deprivation for normal growth. Altering the light exposure schedule is responsible for the transition from one growth stage to the next.

Water: H2O is life. Plants need water for metabolic processes. It ensures that the marijuana plant remains hydrated. Water also acts as a conduit by which minerals are transported to several plant parts (leaves, stems, branches, buds, etc.)

CO2: Carbon dioxide is an essential element in photosynthesis, the process by which plants make food. 

Nutrients: During different growth stages, a cannabis plant will need different amounts of macronutrients (Nitrogen, Phosphorus, and Potassium), secondary nutrients (Magnesium, Calcium, and Sulfur), and micronutrients (Boron, Iron, Manganese, Zinc, and Copper).

Humidity: Unfavorable humidity levels could be the reason you experience disappointing yields. Too much of it leads to contamination, pests, diseases, and bud rot, while low humidity causes dehydration, heat burn, and nutrient burn. Optimum humidity levels for cannabis plants range between 40% and 70%. 

PH: The ideal PH for cultivating cannabis varies with the growing medium of your choice. A deviation to any of the two extremes (acidity or alkalinity) may prevent the absorption of some of the essential nutrients highlighted above.

Soil: 6 to 6.8

Coco fiber: 5.2 to 6.8

Hydroponics: 5.5 to 6.5

Temperature: Cannabis plants thrive in temperatures ranging from 64°F to 80°F (18°C to 27°C). 

Without further ado, let us look into the different stages of marijuana growth and how you can utilize the factors above for the impressive yield you crave;

Germination Stage – takes 2 to 10 days. 

Every luscious, dense, and healthy-looking cannabis plant you see once started as a seed. It is during the germination stage that the plant starts its journey to producing those trichome-filled, sticky buds. But before beginning the process, you need to ensure that the seeds you have picked are viable and from a reputable seed bank such as Marijuana Seed City. Such seeds guarantee you a 90+% growth rate success. 

Germination stages of marijuana growth

A viable seed should be hard, dry, light or dark brown, and have some stripes. If the seed is green or white and feels soft and squishy on the touch, it most certainly won’t germinate. For a cannabis seed to germinate, it needs warmth, darkness, and humidity. Cultivators have different methods of germinating cannabis seeds. The most popular ones are:

  • The paper towel method.
  • Planting them directly in the soil.
  • Soaking the seeds overnight.
  • Using starter cubes and seedling plugs. 

With the first method, you need to take a plate, place a moist paper towel, and then put the seeds on top. Take another moist paper towel, cover the seed and finally cover with another plate. Keep the seeds in a dark place and the paper towels moist at all times. Planting the seed in soil is a straightforward process that requires you to dig half an inch to one inch into the soil, place a seed inside, and cover it with soil. 

The third method involves soaking the seeds in lukewarm water for 24 hours to activate their growth hormones and soften the shell. After 24 hours, subject the seed to optimum conditions, and germination should start in a matter of hours or days. The starter packs and seedling plug is the easiest method, but you need to spend some cash for them. You need to place the seeds in the cube and add a little bit of water, the seeds in a dark and warm place, and wait for the magic to happen.

Whichever method you choose, ensure that the plants enjoy some peace for a seamless germination process. The seed transitions into the seedling stage when the taproot and the stem break out from the seed casing/shell to form the plant’s roots and first leaves (cotyledon leaves), respectively. The entire process may take 2 to 10 days on average, although some seeds may germinate within a day and others up to 2 weeks. 

After the germination, you need to transplant your plant to the grow medium you intend to cultivate them in: DWC/NFT hydroponic system, coco fiber, or soil. If your preferred genetics is auto, this is the time to put them in their final growth medium. Autoflowers grow from seed to harvest within 8 to 12 weeks. It is imperative to avoid stressing them through constant transplants where it will be hard to recover and adapt to the new growth environment.

Seedling Stage – takes 2 to 3 weeks.

The marijuana seedling stage is characterized by small, fragile plants consisting of leaves with a single ridged blade. As the plant matures, the blades will increase to 3, 5, and 7. Some plants will contain as many as 13 blades, but the average is 5 and 7. This stage lasts between 2 to 3 weeks. During this time, you need to take extra care of the plants as they are highly fragile and susceptible to diseases and mold. Maintain optimum conditions (as highlighted below) for the best yields.

marijuana seedling stage - how long does it take to grow weed

Optimum conditions for a cannabis plant in its seedling stage

Factor Recommended amount
Light intensityFor the best results, utilize grow lights with PPFD levels between 200 and 400. Maintain an optimum distance between the plants and the grow lights as instructed by the manufacturer. When lights are too close, the plants may experience heat burn and when they are too far, the cannabis plants will become elongated trying to reach out to the light.Blue spectrum light preferred
Light exposure timeThe recommended light schedule for a seedling is 18 hours of light and 6 hours of darkness (18/6). A seedling should be exposed to up to 16 hours of light per day so the 16/8 schedule may still be applicable. The plant needs to make enough food to sustain its growth, hence the prolonged light hours.
Temperature 71°F to 81°F (22°C to 27°C)
Humidity 65% to 80%
Nutrients Soil medium – do not use nutrients until the vegetative stageHydroponics and coco fiber – a fraction of diluted seedling nutrients to help create enough food to sustain the plant and root growth. Use the nutrients sparingly and only if you have to as the plants contain enough energy to sustain themselves until the vegetative stage.
PHSoil: 6 to 6.8Coco fiber: 5.2 to 6.8Hydroponics: 5.5 to 6.5
Size of the potUse a considerably small pot that will facilitate easy root growth. The pot should also be porous to allow effective drainage and aeration.
Watering The roots are still young and fragile, so water the plants sparingly. You can spray to prevent water clog. Water the seedling from the stalks as the roots have not spread so much. 

Once the plant grows the first full set of blades on new fan leaves, it transitions into the vegetative stage.

Vegetative stage – takes 1 to 15 weeks.

Rapid vertical growth. Exponential horizontal growth. Those are the two changes the cannabis plants experience during the vegetative stage. You will have to use a larger pot to accommodate the ever-growing roots. The leaves, stems, roots, and branches grow in preparation for the budding stage, where the plant will have to be strong enough to hold the weight of the flowers.

The vegetative stage usually lasts for 2 to 4 weeks for autoflowers, and then they automatically transition to the flowering phase. Outdoor-grown plants will stay in the vegetative stage until the light cycle changes between July and September. The stage can last up to 15+weeks.

vegetative stage of marijuana growth

For indoor-grown plants, the cultivator has full control of how long the plant stays in this stage. The average duration is between 4 to 8weeks, but this may be shortened or extended depending on the intended outcome. For example, when a grower specializes in the ScrOG technique, they may prolong the vegetative for 15 weeks to maximize the plant’s growth. Another cultivator practicing SOG may initiate the transition immediately after the seedling stage. 

As the plant grows, you will notice the plants begin to pre-flower 4 to 5 weeks into the vegetative stage. This is when you determine if your plants are male, female, or hermie. Any plant that forms pre-flowers between the stems and branch (nodes) is female. Get rid of the male and hermie plants as they can pollinate the females, which is something you wouldn’t want unless your purpose for cultivating weed is to breed.

Optimum conditions for a cannabis plant in its vegetative stage

Factor Recommended amount
Light intensityTo facilitate a successful vegetative stage growth, expose the plants to 400 to 600 PPFD light intensity – blue spectrum light. This is sufficient to support optimum growth as the plant prepares for the flowering phase
Light exposure time18/6 is the recommended light schedule for this stage, although some cultivators do utilize the 16/8 and 20/4 schedules. The secret is to expose your plants to enough light to create sufficient energy for their growth while giving them enough time to rest.
Temperature 71°F to 79°F (22°C to 26°C)
Humidity 40% to 60%
Nutrients High Nitrogen, low phosphorus, and potassium. The plant will need an increased amount of nutrients, so make sure you feed them accordingly to avoid under or overfeeding them.
PHSoil: 6 to 6.8Coco fiber: 5.2 to 6.8Hydroponics: 5.5 to 6.5
Size of the potMedium-sized and porous to allow free airflow and drainage
Watering The plants have considerably so you don’t need to water them from the stalk. Ensure the plants are ideally watered to facilitate nutrient absorption and to support the overall health of the plant.

When the plant attains the desired size, alter the light schedule to 12/12 to initiate the transition into the flowering phase. For outdoor plants, the transition will happen when the days shorten as Autumn approaches.

Flowering Stage – takes 7 to 14 weeks.

Finally! The plants are in their last stage of growth. In a few weeks, you will get to enjoy the fruits of your labor. During the flowering stage, the plants’ primary focus is making buds. The plants will be ready for harvest within 7 to 14 weeks, depending on the genetics you choose to cultivate.

flowering stage of marijuana growth

Indica: have the shortest flowering period that lasts between 8 and 10 weeks.

Sativa: take longer than Indicas, explaining why most cultivators prefer growing Indicas than Sativas. The flowering stage lasts for 10 to 12 weeks.

Hybrids: with both Sativa and Indica genetics, the flowering period can be as short as 6weeks or as long as 14 weeks.

The flowering stage is divided into three significant stages as follows;

Initial flowering (phase one)

For the first three weeks, the plant experiences the final growth spurt. Sativas, in particular, may grow up to twice or thrice the size they entered the flowering phase. You will notice substantial growth in the height and thickness of the plant. Buds sites will start forming while the pistils become pronounced.  

Mid-flowering (phase two)

During weeks 4 to 5, the plant stops growing, and all its energy is directed towards making the buds bigger, denser, and luscious. The Pistils take on a darker hue as maturity approaches.

Late flowering (phase three)

At week 6 to 8, the plants will start to indicate signs of maturity: the calyxes will appear swollen, the pistils will take on a dark orange hue and curl inwards, some trichomes will turn amber and others will appear white or milky, and the leaves will appear wilted. 

After week 8, the plants are ready for harvest. When to harvest will depend on whether you prefer harvesting your marijuana flower early, at the recommended time, or later on.

Optimum conditions for a cannabis plant in its flowering stage

Factor Recommended amount
Light intensityAs the plant grows, the ideal light intensity increases. For the flowering stage, you will need to invest in growing light with a PPFD level between 600 to 1000. For more impressive results, you can utilize light with PPFD of more than 1000, but don’t forget to supplement with CO2. Red spectrum light is preferred
Light exposure time12/12 – maintain this schedule as altering it may confuse the plant, which may result in either two things; the plant may revert to the vegetative stage or produce poor yields due to growth disruption.
Temperature 64°F to 79°F (18°C to 26°C). In the flowering stage, the plant will require slightly cooler temperatures.
Humidity 40% to 60%
Nutrients Buy high phosphorus nutrients with average amounts of potassium, and low nitrogen levels
PHSoil: 6 to 6.8Coco fiber: 5.2 to 6.8Hydroponics: 5.5 to 6.5
Size of the potLarge to accommodate the gigantic plants and their diverse root system.
Watering For the first week into the flowering stage, water the plants daily while avoiding a soggy growth medium. Afterward, water them once every 2 to 3 days to encourage deep root growth.

Take away

‘How long does marijuana take to grow’ is one of the most searched questions by aspiring and new cannabis cultivators. Having exhaustively explored the four marijuana plant stages, you can note that it would take you a minimum of 9 weeks and a maximum of 32 weeks before you have to harvest. When subjected to optimum conditions throughout their growth stages, cannabis will produce a bountiful harvest as a reward for your hard work. After the flowering period is complete, you can embark on the harvesting, drying, and curing process. 

Joe Musgrave

Joe Musgrave is a keen 420 blogger who writes about all things cannabis. After harnessing his green thumbed skills through years of working on cannabis farms, Joe now shares his knowledge with the rest of the online 420 community.

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