How Long Does it Take to Grow a Marijuana Plant Indoors?

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by Morgan

Last update:

August 30, 2023

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The total time it takes to grow marijuana plants depends on many factors. These factors, as we discuss below, will determine how long it takes for your weed to be ready for harvest or smoking. On average, it takes about 3 to 4 months to grow a marijuana plant indoors.

A more detailed explanation is that the complete lifecycle of your cannabis plants from seed to harvest can take anywhere from 2 to 7 months, or even more depending on your conditions (like which indoor grow lights or grow tent you are using). That’s quite a long time, but you can shorten it if you use creative growing techniques like the sea of green growing method (SOG) to accelerate the vegetative or flowering stage. This method of growing indoors also brings in better yields.

As a new cannabis grower, it’s important to understand the basics of marijuana growth and how long it takes to grow it indoors. Keep reading to learn more about the step-by-step guidelines for the whole growing process.

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Time needed to grow weed from seedling to harvest

Knowing the exact factors that affect your grow operation will help you budget how much time, money, and effort required to get your marijuana ready for consumption.

Many factors such as the type of cannabis seed strains you want to grow, your indoor growing tent setup, the size of your weed project, and the technique you will use all determine your total growth time. An important point to note is that bigger marijuana plants take longer than small plants grown using the SOG method.

Therefore, weed can take around 12-20 weeks growing indoors. From seed to harvest, it’s around 3-5 months and another extra 2 weeks. The additional 2 weeks can be used to dry and cure your marijuana to improve its potency and retain its natural smell. More information and a detailed breakdown of the total time it takes to grow marijuana are provided in this article to help you plan and achieve your targeted harvest time.

Before you start growing weed

The entire preparation time can take up to 2 weeks or more. This includes the time needed to get your equipment and source for the marijuana seeds or clones. 

Step 1: Getting your equipment (likely 1 day to 2 weeks)

An average of 1 day to 2 weeks may be sufficient for you to purchase all the equipment you will need to cultivate marijuana. You can reduce this time if you buy the equipment at your local hydroponics shop. Once you have all the physical resources necessary to grow weed, the next step entails setting up your growing space and equipment. An average growing setup can take a few hours or a weekend afternoon. The whole process can last a day or 2 weeks, depending on the procedure you used to purchase your equipment and the time needed for shipping (if necessary).

Step 2: Getting your seeds or clones (likely 1 day to 4 weeks)

If you are a regular cannabis grower, you can harvest and preserve seeds from your mature plants. You can also trim off mature buds beneath your marijuana plant before harvesting and keep them as clones (see how to make hashish from trimmings, too).

Alternatively you can obtain clones or seeds from local growers. If this is beyond you, then consider ordering clones or seeds from an Canadian seed bank. Since this alternative involves shipping, the time it takes to receive the seeds can be 1 day to 3 weeks or more. 

Shipping and delivery time depends on the shipping method you use and how fast and reliable the process is. Sometimes your package may get caught up in the logistics process for several days or weeks, especially if you are shipping seeds to the USA. To avoid such delays, always order your seeds from a trustworthy supplier or use a reliable shipper.

How much time is needed to grow Marijuana: stages of growth

Cannabis plants pass through several stages of growth before they are ready for harvesting. During these development stages, the plants require different amounts of nutrients, water, and light. You must understand these stages, their durations, and what each plant needs at every stage. This will help you know when to train your plants, when to trellis them, and when they are ready for harvest. 

These five stages of cannabis growth include:

  1. The germination stage
  2. The seedling stage
  3. The vegetative stage 
  4. Flowering stage 
  5. Harvesting stage

Depending on your cannabis strains and the growing method you use, these stages can last up to 3 or 5 months on average. Here is a breakdown of these stages of growing indoors.

Step 1. Germinate the seeds: 12 hours to 8 days

The first marijuana growth stage is the germination stage. It can last for 12 hours or 8 days. A typical mature cannabis seed should be dry and hard in texture. It should also be dark brown. If the seeds are green or white in color and somehow soft, then they are underdeveloped seeds and may not germinate even under the best conditions. Ensure your seeds are mature and easy to germinate. Alternatively, you can use clones and skip the entire germination phase. 

Once the seeds have sprouted, you can transfer them to a growing medium such as soil. You can grow them in pots or on the ground inside your grow tent (see tent kits for beginners). The plant will develop a tap root that will go deep into the soil as the stem springs upward. 

From the stem, two round-shaped cotyledon leaves will sprout up as the plant springs free from the seed’s protective casing. The new delicate leaves will draw insufficient light the plant needs to grow healthy and strong. As the roots continue to grow, the plant will produce its stalk, followed by buds. At this point, your cannabis plant is now a seedling. Throughout the germination stage, your plants will need an uninterrupted light cycle of 16 hours per day. 

Step 2. Seedling phase: 1 to 4 weeks

Once your cannabis plants have grown into seedlings, they will develop lots of cannabis fan leaves. At first, the leaves will have only a single rigid blade which will culminate into many more blades as time goes by. By the time your plants complete the final growth stage, they will have produced an average of 7 blades per leaf. However, some cannabis strains may develop more than seven blades per leaf.

If you notice your cannabis seedlings are dark green with a vibrant look, then they are growing normally and are healthy. This is also a good indicator that they are receiving sufficient light. However, it would be best if you took care not to feed your plants excess water while in the seedling phase. This is because the small roots only require a minimal amount of water to thrive.

It is also in the seedling phase that your marijuana plant is susceptible to disease and mold. Therefore, always keep your grow space clean and regulate the temperatures to ensure no excess moisture in the growing environment. Furthermore, ensure the plants receive sufficient light. The average light required in the seedling stage is 16 to 18 hours of light per day. Therefore, ensure you have the best type of grow light to help your plants survive this delicate stage.

Step 3. Vegetative phase: 3 weeks to 6 months

Your cannabis plants will begin to grow effectively in the vegetative stage. When your transplanted seedlings reach this point, they start to develop roots and foliage more rapidly. The Vegetative stage is also the time to begin training and topping your cannabis plants. It’s also when your plants require a lot of water around the stock and roots, so you should increase their water intake. 

After 3 weeks in the vegetative stage, the roots will stretch outward, at which point you should concentrate on watering in the soil away from the stalk. This will enable the roots to spread out more efficiently and absorb water, soil and nutrients. When in the vegetative phase, your plants need healthy soil rich in nutrients, so ensure they receive sufficient nitrogen. 

A few weeks into the vegetative phase, and your plants will start producing sex organs. This is the ideal time to determine the male vs female sex of each plant, and get rid of the males. Getting rid of the males in the vegetative phase is significant in preventing them from pollinating the females. In this stage, your plants also require uninterrupted quality light (DIL), so ensure you provide not less than 18 hours of light each day.

Step 4. Flowering phase: 6 weeks to 3 months

The flowering phase is the final stage of the growth of a marijuana plant. Once the plants start flowering, they will develop reisin-like buds, indicating they are healthy, fertile, and with promising yields. Most autoflowering strains start flowering when they are 6 or 8 weeks old, but most Sativa strains typically take a longer flowering time.

If grown outdoors, the plants will naturally start flowering as they absorb natural sunlight. This transition is perfect at the end of summer and the onset of Fall when there is less sunlight. However, you can trigger and accelerate the flowering phase of your indoor grown plants by reducing their light cycle from 18 hours a day to 12 hours.

The flowering phase also contains three different substages, which are the flower initiation period, the mid flowering period, and the late-flowering or ripening stage. The flower initiation period can occur when the plant is 2 to 3 weeks into the flowering stage. At this point, the plant continues its average growth, and the females start to produce pistils, the pre-flowers, that enable buds’ development. 

In the mid flowering stage, your cannabis plants cease to grow, and the newly-developed buds grow thicker and fuller. This phase occurs at the 4th or 5th week of the flowering stage. By week six, your plants will enter the final period of the flowering phase, which is the ripening period or flowering time.

In this phase, the plant’s trichomes increase in density, and the plant develops a sticky texture. When this happens, be sure to pay close attention to the changing colors of the pistils, as this will help you determine if the plants are ready for harvesting.

Step 5. Harvesting: 1 to 5 days

The time needed to harvest cannabis plants varies from one grower to another and the existing conditions necessary to grow cannabis. For instance, harvesting is normally done in Fall for outdoor grown plants. However, indoor plants can be harvested any time of the year since they don’t depend on natural environmental conditions to grow. 

Once your indoor plants attain maturity and the harvesting stage, then it is time to reap the fruits of your careful and delicate labor. The only challenge is knowing when your plants are ready for harvest and how to do it carefully. Early or late harvest may affect the smell, taste, and potency of your marijuana produce. 

Once your plants leave the flowering stage, observe the changing colors of the pistils of your female plants. If the pistils turn slightly brown, then they are ready for harvest. On the other hand, if they are too brown, then your plants are overripe, and you may have missed the crucial moment when you should have harvested them. 

An easier clue to help you ascertain if your marijuana plants are ready is to observe the leaves and stem of the plants. Yellow leaves indicate that the plants are ready for harvesting. Swollen stems and yellow leaves that fall off suggest that the harvest time has passed, and it’s too late to salvage your plants. At this point, your weed will be too bitter and the smell unpleasant, making it worthless. Therefore, the earlier you harvest them, the better.

Final thoughts on the time it takes to grow Marijuana

Growing weed indoors is a delicate process that should be done with precision. Although the average time it takes to grow cannabis indoors is 3 to 5 months, some strains may take less or more time. Therefore, research every strain you choose to work with. Also, ensure you pass your weed through the post-harvest stages, which include drying and curing.

Drying is essential for curbing molds and retaining the plant’s quality. It should last for a week or up to 10 days. Curing, on the other hand, can last for as short as 2 weeks or as long as 6 weeks. Curing allows you to rid the plant of grass, bitter taste, or smell. It also helps maintain the plant’s potency, which is ideal for medicinal applications. 

From the time you obtain equipment, seeds/clones, and begin cultivation till harvest time can take approximately 8 weeks to 5 months or more. You can share your thoughts and suggestions in the comments section.


1. How Much Time Does It Take to Grow a Cannabis Plant?

It depends on the strain of cannabis, but it typically takes between 8 and 10 weeks to grow a cannabis plant.

2. How Long to Flower a Marijuana Plant?

The flowering time of a marijuana plant can vary depending on the strain, but typically it will take between 8 and 12 weeks.

3. What Are the Stages of Growing a Marijuana Plant?

There are typically four stages of growth for a marijuana plant: seedling, vegetative, flowering, and harvest.

The seedling stage is when the plant is just starting to grow. During the vegetative stage, the plant will grow larger and start to form buds. The flowering stage is when the buds will start to grow flowers and the plant will start to produce THC. The harvest stage is when the buds are harvested and the THC is extracted.

4. How Much Light Does a Marijuana Plant Need to Grow?

Marijuana plants need a lot of light to grow. They need at least 18 hours of light per day to grow properly.

5. What Temperature Does a Marijuana Plant Need to Grow?

Marijuana plants need a temperature range of between 70 and 80 degrees Fahrenheit to grow.

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About the author 


I discovered the benefits of Cannabis at a young age in 2002, with years of trial and error, my knowledge grew just like my plants. As my love for cannabis unfolded I began to teach and learn, trying to gain as much information and practical growing experience.

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