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How Long Does It Take to Grow Cannabis From Seed?
Growing cannabis from seed is a meticulous and rewarding process that requires time, care, and environmental control. The full lifecycle from seed to harvest can range from 3 to 8 months, depending on the strain, growing methods, and desired outcomes. This timeline includes several key stages: germination, seedling, vegetative, and flowering, with post-harvest processes such as drying and curing adding more time before consumption.
1. Germination Stage (1–7 days)
Overview:
Germination is the process of coaxing a cannabis seed to sprout a root (taproot). This initial phase typically takes 1 to 7 days, though most seeds germinate within 48–72 hours under optimal conditions.
Key Requirements:
- Warmth: 70–85°F (21–29°C)
- Humidity: 70–90%
- Darkness or low light
- Moisture: Damp (not soaked) medium such as paper towel or peat plug
What Happens:
The seed absorbs moisture, swells, and cracks open. A white taproot emerges and soon after, the first embryonic leaves (cotyledons) push upward.
2. Seedling Stage (1–3 weeks)
Overview:
The seedling stage begins once the sprout breaks through the soil or growing medium and develops its first true leaves (serrated edges). This phase typically lasts 1 to 3 weeks.
Key Requirements:
- Light: 18–24 hours per day of fluorescent or LED grow light
- Temperature: 68–77°F (20–25°C)
- Humidity: 65–80%
- Low nutrients: Avoid overfeeding
What Happens:
The seedling develops a stronger root system and begins producing more leaves. During this stage, it is sensitive to overwatering, excess nutrients, and poor light. Healthy seedlings will grow 2–4 inches tall with several nodes (leaf sites).
3. Vegetative Stage (2–8 weeks or more)
Overview:
In the vegetative stage, the cannabis plant focuses on growing stems, branches, and leaves, building a strong framework to support future flowers. This phase typically lasts 2 to 8 weeks indoors but can go longer, especially outdoors or in training techniques like SCROG or LST.
Key Requirements:
- Light: 18–24 hours per day (indoors); full sun (outdoors)
- Temperature: 70–85°F (21–29°C)
- Humidity: 50–70%
- Nutrients: Higher nitrogen for growth
- Training: Topping, fimming, pruning, etc.
What Happens:
Plants grow rapidly in size. Leafy growth expands, and pre-flowers may start to appear near nodes (indicating sex if growing from regular seeds). Indoor growers may choose to keep this phase short or extend it for a larger yield. Outdoor plants stay in this phase until daylight hours shorten naturally.
4. Flowering Stage (6–12 weeks)
Overview:
This is the reproductive stage where the plant produces buds (flowers). Flowering is triggered when the light cycle changes to 12 hours of light and 12 hours of darkness, mimicking fall conditions. Autoflowering strains enter flowering based on age, regardless of light.
Timeframe:
- Indica strains: 6–8 weeks (shorter flowering cycle)
- Sativa strains: 10–12+ weeks (longer flowering cycle)
- Hybrids: 8–10 weeks
- Autoflowers: Entire lifecycle 8–12 weeks from seed
Key Requirements:
- Light: 12/12 cycle (unless autoflower)
- Temperature: 65–80°F (18–27°C)
- Humidity: 40–50% (lower to prevent mold)
- Nutrients: Higher in phosphorus and potassium
What Happens:
- Plants stop vertical growth (stretch) in the early flowering phase
- Buds begin to form and swell
- Trichomes develop, and pistils (white hairs) emerge
- Aromas become stronger
- By late flowering, pistils darken, and trichomes change from clear to milky to amber (signs of maturity)
5. Harvest Timing (Varies by Strain and Grower Goals)
How to Know When to Harvest:
- Pistils: When 70–90% have darkened or curled in
- Trichomes: Using a magnifying glass or microscope:
- Clear trichomes = not ready
- Milky/cloudy = peak THC
- Amber = more sedative effect (CBN formation)
Harvest timing can affect cannabinoid profiles and effects:
- Early harvest: More energizing, higher THC
- Late harvest: More sedating, higher CBN
6. Post-Harvest: Drying and Curing (2–4+ weeks)
Even though plants are technically “harvested,” they aren’t ready for use until dried and cured properly.
Drying (7–14 days):
- Hang buds upside-down in a dark, ventilated space
- Temp: 60–70°F (15–21°C)
- Humidity: 50–60%
- Buds are dry when stems snap instead of bend
Curing (2–6 weeks+):
- Place dried buds in airtight jars (e.g., mason jars)
- Open jars daily for 10–15 minutes to release moisture (burping)
- Store in cool, dark area
- Improves flavor, potency, and smoothness
Some connoisseurs cure for several months to develop terpene profiles fully.
Summary Table of Growth Timeline
| Stage | Timeframe | Notes |
|---|---|---|
| Germination | 1–7 days | Taproot emerges |
| Seedling | 1–3 weeks | First true leaves grow |
| Vegetative | 2–8+ weeks | Plant structure develops |
| Flowering | 6–12+ weeks | Buds form and ripen |
| Drying | 7–14 days | Prepares for storage |
| Curing | 2–6+ weeks | Improves taste and potency |
| Total Time | 3–8 months | Depending on strain and method |
Factors Affecting Total Growth Time
- Strain Type (Genetics):
- Indica: Generally faster to mature
- Sativa: Slower but taller and larger-yielding
- Autoflowers: Fastest (8–10 weeks total from seed)
- Photoperiod: Slower but can be controlled
- Growing Environment:
- Indoor: Full control, but requires equipment (lights, fans, timers)
- Outdoor: Seasonal and climate-dependent
- Greenhouse: Hybrid method with natural light and protection
- Light Cycle and Intensity:
- Photoperiod plants need strict 12/12 for flowering
- Insufficient light can stunt growth and extend time
- Grower Technique:
- Training methods (LST, HST, SCROG) can extend vegetative stage but increase yields
- Topping delays flowering but promotes bushier growth
- Nutrient Schedule:
- Overfeeding or deficiencies can slow growth
- Organic vs synthetic nutrients can impact speed
- Stress and Pests:
- Stress (e.g., overwatering, heat, light burn) delays development
- Pests and disease may force early harvest or cause stunting
Autoflower vs. Photoperiod Seeds: Time Comparison
| Type | Germ to Harvest | Light Cycle Needs |
|---|---|---|
| Autoflower | 8–12 weeks | Any (18/6 often used) |
| Photoperiod | 3–5+ months | Needs 12/12 to flower |
Autoflowers are ideal for beginner growers or those seeking fast turnover. Photoperiods offer more control over size, yield, and potency.
Conclusion
Growing cannabis from seed is a process that can take anywhere from 3 to 8 months, depending on strain genetics, environmental conditions, and cultivation techniques. Each stage of growth germination, seedling, vegetative, flowering, and post-harvest curing plays an essential part of the finished product’s efficacy and quality. Understanding and respecting these timelines enables growers to produce high-quality cannabis with optimal cannabinoid and terpene profiles, whether for medical or recreational use. Patience, attention to detail, and environmental control are the keys to success.
