How long do cannabis seeds take to germinate or mature

Growing cannabis is a process that requires time, patience and a solid understanding of the plant’s life cycle. If you're new to cultivation, one of the first questions you may ask is: how long do cannabis seeds take to germinate? And once they sprout, how long until they reach full maturity and are ready for harvest?

In this guide, we’ll break down the entire timeline from seed germination to harvest, covering every key growth stage. Whether you’re growing indoors or outdoors in the United Kingdom, this knowledge will help you plan your grow cycle and set realistic expectations.

At Mavericks Genetics, we supply top-quality cannabis seeds bred for rapid germination, stable growth and high yields. Let’s take a closer look at what to expect from start to finish.

How long does it take cannabis seeds to germinate

Average germination time: 1 to 7 days

Under optimal conditions, cannabis seeds usually germinate within 24 to 72 hours, though some may take up to a full week.

Key germination factors:

• Moisture: Seeds need to absorb water to activate enzymes.

• Temperature: 21–27°C is ideal.

• Darkness: Seeds germinate best in dark, humid environments.

• Viability: Older or poorly stored seeds may take longer or fail to germinate.

Using the paper towel method, most viable seeds from Mavericks Genetics will produce a visible taproot within 1 to 3 days.

Germination methods and timelines

Whichever method you choose, once the white taproot appears, the seed is ready to plant.

How long does it take for a cannabis seed to mature

After germination, the seed progresses through four main growth stages:

• Seedling stage: 1–2 weeks

• Vegetative stage: 3–8 weeks

• Flowering stage: 6–12 weeks

• Harvest and curing: 2–4 weeks

Total time from seed to harvest:

• Autoflower seeds: 8 to 12 weeks

• Photoperiod seeds (indoor): 12 to 20 weeks

• Photoperiod seeds (outdoor in the UK): Sow in spring, harvest in autumn (4 to 6 months)

Let’s examine each stage in more detail.

Stage 1: Seedling stage (1–2 weeks after planting)

After planting, the germinated seed breaks through the soil as a seedling. It produces cotyledons (rounded embryonic leaves) followed by its first serrated true leaves.

Ideal conditions:

• Temperature: 21–25°C

• Humidity: 60–70%

• Light: 18–24 hours of low-intensity light per day

Seedlings are delicate and sensitive to overwatering, high temperatures and poor airflow. Keep the medium lightly moist, never saturated.

Stage 2: Vegetative stage (3–8 weeks)

This is the period of vigorous growth where the plant builds its structure—stems, leaves and roots.

Factors affecting the vegetative stage:

• Photoperiod plants: Can remain in veg indefinitely under 18 hours of light; most growers veg for 4–6 weeks.

• Autoflowers: Enter flowering automatically after 2–4 weeks, regardless of light cycle.

Key care tips:

• Repot if root space is limited

• Use nitrogen-rich nutrients

• Maintain temperatures between 22–28°C

• Gradually reduce humidity to 50–60%

Stage 3: Flowering stage (6–12 weeks)

This stage marks the formation of buds. For photoperiod strains, it is triggered by switching the light schedule to 12 hours of light and 12 of darkness.

Flowering timeline overview:

• Weeks 1–2: Rapid vertical growth (pre-flower stretch)

• Weeks 3–5: Buds begin to form, pistils emerge

• Weeks 6–8: Buds swell, trichomes develop

• Weeks 9–12: Trichomes ripen, changing to cloudy or amber

Flowering time by strain type:

Always check the strain recommendations from Mavericks Genetics for precise timing.

Stage 4: Harvest, drying and curing (2–4 weeks)

Once flowering is complete, it’s time to harvest and dry your buds, then cure them to enhance taste, potency and longevity.

When to harvest:

• 70–90% of pistils have darkened

• Trichomes are mostly milky with some amber

• Fan leaves start yellowing naturally

Post-harvest steps:

• Drying: Hang buds in a dark, ventilated room for 7–14 days (45–55% humidity)

• Curing: Place in airtight jars for 2–4 weeks, burping daily

Curing is optional but highly advised to enhance smoothness and preserve terpenes.

Total time from seed to smoke

These are average estimates and may vary depending on environment, genetics and grow method.

Factors that can slow germination or growth

• Low-quality or aged seeds

• Incorrect temperature

• Overwatering or poor drainage

• Lack of oxygen around the roots

• Inadequate lighting

• Nutrient imbalances

For best results, begin your grow with premium seeds from a trusted source like Mavericks Genetics.

Tips to speed up your grow cycle

• Choose autoflower strains for fastest results

• Start seedlings indoors in a controlled environment

• Use coco coir or hydroponics for faster root development

• Select fast-flowering photoperiod strains

• Use full-spectrum LED lights at optimal intensity

Explore our autoflower collection for quick and easy grow options.

Frequently asked questions

Can cannabis seeds germinate in 24 hours?

Yes. Fresh, high-quality seeds can sprout in 24 hours using the paper towel method in warm, moist conditions.

Why are my seeds taking over a week to germinate?

It could be due to old seeds, low humidity, cold temperatures or low oxygen. Ensure your environment meets ideal germination conditions.

How can I tell when to harvest?

Use a magnifying glass or jeweller’s loupe to check the trichomes. When they are mostly cloudy with some amber, your plant is ready.

Conclusion: Understand the timeline, grow with confidence

Germinating cannabis seeds is just the beginning of a journey that takes several weeks or months. By understanding the complete timeline from seed to harvest, you can better plan your grow and manage expectations.

Start with strong genetics, follow best practices for each growth stage and provide the ideal environment to maximise your plant’s potential.

Ready to grow?
Visit Mavericks Genetics to explore our feminised, autoflower and photoperiod cannabis seeds—bred for rapid germination and outstanding yields.