How Long Does It Take To Grow Cannabis Indoors or Outdoors? A Full Breakdown

The process of growing cannabis from seed to harvest typically takes anywhere from four to eight months to grow marijuana. This timeline depends on various factors, including whether you grow your plants indoors or outdoors, the specific cannabis strain, and the environmental conditions you maintain throughout the plant’s lifecycle.

Indoor growers often have the advantage of controlling light cycles, temperature, humidity, and air quality, which can shorten the growth timeline significantly. In contrast, outdoor growers must work within seasonal constraints, making the entire process take longer and more dependent on regional climate.To better understand how long it takes to grow cannabis, it’s important to become familiar with each stage of the plant’s growth and how long each stage lasts.

The Cannabis Growth Stages

Cannabis plants go through six main stages during their lifecycle: germination, seedling, vegetative, pre-flowering, flowering, and harvesting. Each stage of the cannabis lifecycle plays a vital role in the plant’s development and requires unique care and environmental conditions to grow marijuana effectively.

Germination: 1 to 7 Days

Germination marks the beginning of the cannabis lifecycle, essential for any successful marijuana grow, especially when using feminized seeds to sprout healthy plants. For a seed to germinate properly, it must be mature—typically firm, dry, and brown in color—especially when using feminized seeds to grow weed. Once exposed to moisture and darkness, the seed begins to sprout and push out a small root called a radicle.

Many growers place cannabis seeds in a damp paper towel or soak them in water for a day or two, then leave them in a dark, warm space to encourage germination. Once the cannabis seed root appears, it is ready to be planted in a suitable medium to grow plants. In about one to seven days, the seed breaks through the soil surface and starts developing its first leaves, known as cotyledons, marking the initial phase of the plant grow as you begin to take to grow weed.

Seedling Stage: 2 to 3 Weeks

The seedling stage is a delicate phase where the plant establishes its first true leaves and begins basic photosynthesis, which is crucial for healthy plants to grow. During this time, seedlings need to grow under 18 to 24 hours of grow light per day, mild humidity, and careful watering.

Overwatering is a common mistake at this stage, as young roots are highly sensitive and need to grow in well-drained conditions. A healthy seedling will develop more cannabis-like leaves over time, starting with one or three “fingers” and eventually producing leaves with five to seven serrated fingers, which is important for plant growth. The seedling stage typically lasts about two to three weeks.

Vegetative Stage: 2 to 8 Weeks

Once the seedling has developed at least seven sets of leaves, it transitions into the vegetative stage. This is the phase of rapid growth when the plant’s root system expands, stems thicken, and foliage multiplies, which is crucial to grow weed successfully.

Cannabis plants in the vegetative stage benefit from increased water, nutrients high in nitrogen, and lots of light—often around 18 hours a day if grown indoors in a grow tent. The plant may grow anywhere from a few inches to several feet tall during this period, depending on genetics and environmental factors. Training techniques such as topping or low-stress training can also be applied at this stage to shape the plant and improve yields.

The vegetative stage can last anywhere from two weeks to two months. Indoor growers have the flexibility to keep plants in this vegetative growth stage longer if desired, while outdoor growers are limited by the length of the growing season.

Pre-Flowering Stage: 1 to 2 Weeks

The pre-flowering stage begins when the plant starts to show signs of its sex—usually between the fourth and sixth week of growth. This short phase lasts about one to two weeks and is critical for identifying and removing male or intersex plants before they can pollinate the females, ensuring a successful plant grow.

Female marijuana plants develop white, hair-like pistils at their nodes, while male plants form small pollen sacs. If allowed to mature, male plants can pollinate nearby females, resulting in seedy, lower-quality buds. Intersex plants, or hermaphrodites, should also be removed, as they can self-pollinate and compromise your harvest, affecting the overall yield of your plant grow.

The plant’s structure also starts to shift during this phase, preparing it for the production of flowers in the next stage.

Flowering Stage: 6 to 8 Weeks (or Longer)

The flowering stage is when cannabis plants begin to form buds—the parts of the plant harvested for consumption. For indoor growers, flowering is initiated by changing the light cycle to 12 hours of light and 12 hours of darkness each day, allowing plants to grow effectively. Outdoor plants enter this stage naturally as daylight hours shorten toward the end of summer, allowing them to sprout and grow effectively.

During flowering, the plant diverts most of its energy into producing flowers rich in cannabinoids like THC and CBD, which are essential for creating potent cannabis buds. You’ll notice the appearance of trichomes—tiny, crystal-like glands that cover the buds and leaves—and a stronger aroma.

Cannabis plants require blooming nutrients, slightly lower humidity, and stable temperatures during this time. The flowering phase usually lasts between six and eight weeks, but some sativa-dominant strains can take up to 12 weeks or more to grow weed.

You’ll know your plant is ready for harvest when the trichomes change from clear to cloudy to amber, and the pistils darken from white to reddish-orange, indicating it’s time to grow marijuana. The color and condition of these indicators help determine the plant’s cannabinoid content and overall effects.

Harvesting, Drying, and Curing: 2 to 4 Weeks

After flowering is complete, the cannabis plant is ready to be harvested. Growers typically cut down the plant in sections to make drying easier, which is a vital step in the overall cannabis cultivation process to ensure the best quality for those who want to grow outdoors. These branches are then hung upside down in a cool, dark, and well-ventilated area for about 7 to 14 days, with a relative humidity of 40 to 50 percent, which is important for the drying process in cannabis cultivation.

Drying cannabis too quickly can lead to harsh flavor and a poor smoking experience, which can be detrimental for those who grow weed indoors, as it affects the quality of the cannabis buds. Once dried, many growers proceed to the curing stage in cannabis cultivation, which involves placing the buds in airtight containers like mason jars for one to three weeks. These jars should be opened daily to allow fresh air in and let gases escape, which is crucial during the curing stage of cannabis cultivation.

Curing helps preserve cannabinoids and terpenes, enhances flavor, and smooths the final product. Skipping this step can result in harsh smoke and diminished potency in your marijuana grow, affecting the overall quality of the plant grow.

The Importance of Air Filtration

Cannabis plants are sensitive to changes in air quality, especially when grown indoors for marijuana. A well-ventilated environment with clean, filtered air helps prevent mold, bacteria, and pests, which can damage your crop and affect plant development at every stage.

Using grow room air filtration systems ensures that cannabis plants receive clean air from germination through curing. These systems remove airborne contaminants and odors, balance humidity and CO2 levels, and maintain overall plant health, which is crucial for successful cannabis cultivation.

Without proper airflow, indoor grow spaces can experience stagnant air pockets and harmful humidity swings, both of which can compromise your entire yield when you want to grow cannabis.

Final Thoughts

So, how long does it take to grow cannabis? From start to finish, the timeline to grow weed indoors ranges between four and eight months depending on your growing method and how long you choose to keep your plants in the vegetative growth phase. By understanding the distinct stages of growth—germination, seedling, vegetative, pre-flowering, flowering, and harvesting—you can optimize conditions for a healthy and productive plant when you start growing.

Whether you’re a first-time grower or an experienced cultivator, success lies in the details. Pay close attention to your environment, plant nutrition, and air quality, and you’ll be well on your way to harvesting high-quality cannabis.

Frequently Asked Questions

How long does it take to grow cannabis indoors?

Indoor cannabis grows typically take four to six months, depending on how long you keep the plant in the vegetative phase and the specific strain.

What’s the shortest time to harvest cannabis?

Fast-growing autoflowering strains can be harvested in as little as 10 to 12 weeks from seed, making them ideal for quick indoor grows with grow lights.

Can you speed up the cannabis growing process?

You can shorten the vegetative stage by adjusting light cycles and choosing fast-growing strains, but rushing the process too much can sacrifice quality.

How do I know when my cannabis is ready to harvest?

Look for cloudy or amber trichomes and darkened pistils to determine the best time to harvest your cannabis buds. These visual cues indicate peak potency and ripeness, essential factors to consider when planning your plant grow.

Why is drying and curing important?

Proper drying and curing preserve flavor, increase cannabinoid stability, and result in a smoother smoking experience for those who grow weed indoors.