Quick Glance
How long does it take for cannabis to grow?
Growing cannabis takes about 3 to 5 months from seed to harvest. However, the right time to harvest depends on many factors.
This guide will explain the cannabis growth cycle, the best harvest time, important factors that affect harvest timing, and how to tell when your plants are ready.
1.Cannabis Growth Stages
Cannabis grows in two main stages: vegetative stage (growth stage) and flowering stage. The time for each stage depends on the strain, light conditions, and growing method.
1.1 Vegetative Stage (4-6 weeks)
This is when cannabis plants grow leaves and roots. It usually lasts 4-6 weeks.
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Light: 16-18 hours per day (Use full-spectrum LED lights)
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Temperature & Humidity: 22-28ยฐC / 60-70% RH
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Nutrients: High nitrogen (3-1-2 NPK), fertilize every 10 days
Tips for South Africa:
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In summer, use fans for ventilation due to high temperatures.
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In winter, use greenhouse lighting to extend the vegetative stage.
1.2 Flowering Stage (8-10 weeks)
This is when the plant starts making buds. The flowering stage is longer than the vegetative stage.
| Stage | Duration | Signs | Key Actions |
|---|---|---|---|
| Early Bloom | 1-2 weeks | White hair-like pistils appear | Switch to 12/12 light cycle |
| Bud Growth | 3-6 weeks | Trichomes (resin glands) form | Increase phosphorus and potassium (1-3-2 NPK) |
| Maturity | 7-10 weeks | Pistils change color, trichomes turn cloudy | Reduce watering gradually |
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Sativa strains take longer to flower than Indica strains.
2. 5 Factors That Affect Harvest Timing
2.1 Cannabis Strain
Different strains have different growth cycles. Popular cannabis strains in South Africa include:
| Rank | Strain Name | Growth Time | Common Use |
|---|---|---|---|
| 1 | Durban Poison | 10-12 weeks | Uplifting, good for focus |
| 2 | Swazi Gold | 8-9 weeks | Relaxing, euphoric |
| 3 | Transkei Gold | 11-13 weeks | Strong effects, unique flavor |
| 4 | Malawi Gold | 16-18 weeks | Long-lasting effects |
| 5 | Africa Sativa | 16-18 weeks | Energizing, grows well in South Africa |
| 6 | Rooibaard | 14-16 weeks | Hardy, adaptable |
| 7 | White Widow | 12-14 weeks | Strong, relaxing effects |
2.2 Light Cycle
Cannabis plants need different light cycles in different stages:
| Stage | Light Requirement | Best Timing |
|---|---|---|
| Vegetative Stage | 16-18 hours of light per day | 18 hours light / 6 hours dark |
| Flowering Stage | 12 hours of light per day | 12 hours light / 12 hours dark |
Recommended๏ผ grow light south Africa
1.800W Full-spectrum LED grow lightsย
2. 200W quantum board grow light
2.3 Temperature & Humidity
| Technique | Best for | Benefits | Drawbacks | Effect on Harvest Timing |
|---|---|---|---|---|
| Sea of Green (SOG) | Indica strains | Faster harvest, high yield | Harder to manage, needs strong light | Shortens growth cycle |
| Low-Stress Training (LST) | Autoflower & photoperiod strains | Even growth, more yield | Needs regular maintenance | Can speed up flowering |
| Topping | Photoperiod strains | More branches, higher yield | Must trim at right time | Promotes faster flowering |
| Super Cropping | Photoperiod strains | Stronger plant, bigger harvest | Risk of damage if done wrong | Encourages faster bloom |
| Screen of Green (ScrOG) | Photoperiod strains | Better light exposure | More work required | Speeds up flowering |
Note: If humidity is above 60% in flowering stage, mold may develop.
2.4 Growing Techniques
Different growing techniques can speed up growth and increase yield.
| Technique | Best for | Benefits | Drawbacks | Effect on Harvest Timing |
|---|---|---|---|---|
| Sea of Green (SOG) | Indica strains | Faster harvest, high yield | Harder to manage, needs strong light | Shortens growth cycle |
| Low-Stress Training (LST) | Autoflower & photoperiod strains | Even growth, more yield | Needs regular maintenance | Can speed up flowering |
| Topping | Photoperiod strains | More branches, higher yield | Must trim at right time | Promotes faster flowering |
| Super Cropping | Photoperiod strains | Stronger plant, bigger harvest | Risk of damage if done wrong | Encourages faster bloom |
| Screen of Green (ScrOG) | Photoperiod strains | Better light exposure | More work required | Speeds up flowering |
ย 3. How to Tell When Cannabis is Ready to Harvest
You cannot rely only on a calendar. You need to look for specific signs that your cannabis is ready to harvest.
3.1 Check the Trichomes
Trichomes are the tiny crystal-like glands on cannabis buds. They contain THC and CBD. Use a 40x magnifier to check their color.
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Clear: Not ready, THC levels are low.
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Milky White: Best time to harvest, highest THC levels.
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Amber: Slightly overripe, lower THC but more relaxing effects.
3.2 Look at the Buds and Leaves
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Buds change color from green to purple, red, or yellow.
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Leaves turn yellow and may start falling off.
3.3 Smell and Touch
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Mature buds feel firm and dense.
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Strong, pungent smell means the plant is ready.
Tip: Use a 10x-40x magnifier to check the trichomes for accurate results.
Conclusion
The best time to harvest depends on the cannabis strain, growing conditions, and timing. The best sign is when trichomes turn milky white.
Harvesting at the right time ensures the best potency and flavor.
5.FAQย
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Q: How long does cannabis take to grow?
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A: 3 to 5 months from seed to harvest, depending on the strain and conditions.
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Q: How do I know my cannabis is ready to harvest?
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A: Check trichomes with a magnifier. When they turn milky white, it's time to harvest.
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Q: What happens if I harvest too early or too late?
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A: Too early = weak effects, too late = lower potency and bitter taste.
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Q: How many cannabis plants can I grow at home in South Africa?
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A: The 2018 law allows up to 4 plants for private use, but selling is illegal.
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