How Long Does It Take for Weed to Grow 

Generally, from seed germination to harvest, a whole weed life cycle can take anywhere from 3 to 8 months, unless you start with cloned weed. To be more precise, growing marijuana indoors or outdoors makes a huge difference in how long the weed takes to grow, considering the variations in light, temperature, and humidity levels. 

When the weed plant steps into the vegetative stage, indoor growers have the flexibility to induce flowering relatively early, either when the plant is small after a few weeks or later when it has grown substantially. Outdoor cultivation, on the other hand, is subject to seasonal changes, requiring patience until the fall when plants naturally flower and are ready for harvest. In this post, we will focus on indoor marijuana growing. 

Here’s a quick preview of the whole weed life cycle:

• Germinating: 1-7 days
• Seedling: 2-3 weeks
• Vegetative: 3-16 weeks
• Pre-Flowering: 1-2 weeks
• Flowering: 6-8 weeks
• Harvesting

Stage 1: Seed Germination (1-7 Days)

The journey begins with the magical process of seed germination. Seeds hold the potential for life, and unlocking this potential is the first step towards a thriving cannabis plant. 

A healthy weed seed feels dry and hard, having a hue of dark brown. If you use paper towels to germinate weed seed, you should notice the seed cracks open, and a small white root (taproot) emerges after 1-7 days. 

• Light: Minimal light required. Focus on warmth and moisture rather than light.
• Temperature: Ideal range is between 70-85°F (21-29°C).
• Humidity: High humidity levels, around 70-90%, are beneficial.

Stage 2: Seedling Stage (2-3 Weeks)

As the seed germinates, it gives birth to a seedling – a fragile yet resilient entity. This stage is characterized by the emergence of the first leaves and the establishment of the plant's root system. 

The first small round leaves (cotyledons) emerge, followed by the first set of true cannabis leaves that are serrated. These seedlings are delicate with a thin stem. The plant develops more sets of leaves, and the true cannabis leaves will grow more serrated fingers (typically 5-7 per leaf).

During the seedling phase, three things are worth catching your attention. 

• First, since the plant's tiny roots require only a minimal amount of water, you should carefully evaluate the moisture level before watering the plants. 
• Second, the weed plant is susceptible to diseases and mold at this stage. Maintaining a clean environment and controlling moisture levels is important. 
• Ensure that the plant receives ample light for 18 hours a day indoors for optimal growth. Regardless of growing marijuana indoors or outdoors, you’d better apply artificial grow lights to help your plants go through this vulnerable phase. 

Stage 3: Vegetative Stage (3-16 Weeks)

Here comes the most thriving stage where your plants truly take off by transforming light into photosynthesis. With the seedling stage behind, the plant is normally transplanted into a larger pot and enters the vegetative phase. During this period, the focus shifts to leaf and stem development. Rapid growth with vibrant green, fan-like leaves. The plant becomes bushier and taller, with a thicker stem. Sativa plants typically exhibit a tall, lean structure with fewer leaves, while Indica plants are shorter and more densely foliated. 

Unlike the seedling stage, weed plants in the vegetative phase require much more water, a steady supply of moist air, and nutrients rich in nitrogen and potassium to support fast growth. 

• Light: Stronger light is necessary. Full-spectrum LED grow lights are recommended for 18-24 hours per day.
• Temperature: Daytime temperatures should be between 70-85°F (21-29°C), with a drop of 10-15 degrees at night.
• Humidity: Reduce humidity gradually to about 40-60% as plants grow larger.

Stage 4: Pre-Flowering Stage (1-2 Weeks)

Image source: leafwell.com

As the plant matures, it enters the pre-flowering stage, marked by the appearance of gender-specific signs. You are likely to have male, female, and hermie plants during this time. Luckily, we have a series of articles on cannabis genders:

• How to Turn A Hermie Back into A Female 
• How to Identify A Female Seed 
• How to Identify and Use Male Cannabis Plant

Stage 5: Flowering Stage (6-8 Weeks)

The flowering stage is perhaps the most awaited phase for cannabis cultivators. It is during this period that the plant devotes its energy to producing flowers – the coveted buds. To make it more clear, the flowering stage comprises two distinct subphases:

• Mid-Flowering (Week 1-2): The plant’s vertical growth halts, and the focus shifts to the buds, which begin to increase in size.
• Late Flowering/Ripening (Week 3 onwards): There is a noticeable increase in trichome density, making the plants sticky. Monitoring the color of the pistils is important to determine the right harvest time.

When transitioning from the vegetative to the flowering stage, several adjustments are needed:

• Pruning Avoidance: Refrain from pruning during flowering, as it can disrupt the plant's hormonal balance.
• Support and Airflow: Employ trellising or the Screen of Green (SCROG) method to support the developing buds and facilitate air circulation.
• Nutritional Changes: Consider introducing bloom or phosphorus-rich nutrients to support this critical stage.

Stage 6: Harvesting

You can tell your cannabis plant is ready for harvest when the pistils on the cola buds change color from white to a reddish-orange, and the trichome heads evolve from clear to milky, opaque, and finally to amber. The amber hue suggests a higher CBD to THC ratio in the resin. 

Once harvested, the journey continues with the drying and curing process, which are crucial for preserving the flavor, aroma, and potency of the buds. 

Conclusion

Each growth stage of the weed plant, from the fragile seedling phase to the vigorous vegetative growth and the defining flowering period, requires specific care. The culmination in the harvest stage, where growers reap the rewards of their efforts, is marked by the plant's transformation and bud development. This journey through cannabis cultivation offers a fulfilling experience, packed with challenges and triumphs.