Nutrient Feeding
🧪 Nutrient Feeding Schedule for Cannabis Growth Stages
Introduction
Proper cannabis feeding ensures vigorous growth, potent buds, and optimal yields. Nutrient needs change as the plant progresses from seedling to harvest. If the feeding is unbalanced, deficiencies or toxicities can occur. This guide walks you through stage-by-stage feeding for healthy cannabis cultivation.
Primary Nutrients (NPK)
- Nitrogen (N): For leaf and stem growth – essential in vegetative stage
- Phosphorus (P): Root development, flowering – crucial during bloom
- Potassium (K): Overall health, resistance, and bud density – needed throughout
Micronutrients
Includes calcium, magnesium, sulfur, iron, boron, zinc, etc.—used in small amounts but critically important. Deficiencies cause serious plant issues.
Nutrient Requirements by Stage
| Stage | Nitrogen (N) | Phosphorus (P) | Potassium (K) | Approx EC | Approx TDS (ppm) |
| Seedling | Low | Very Low | Low | 0.4–0.6 | 200–300 |
| Vegetative | High | Medium | Medium | 0.8–1.2 | 400–800 |
| Early Flowering | Medium | High | High | 1.2–1.6 | 800–1200 |
| Peak Flowering | Low | High | Very High | 1.6–2.0 | 1000–1400 |
| Final Flush | Zero | Zero | Zero | < 0.4 | < 200 |
Weekly Feeding Schedule
Week 1–2 (Seedling):
- Only pH-adjusted water
- Optional mild root stimulator
Week 3–6 (Veg):
- High nitrogen (e.g., NPK 3-1-2)
- Add Cal-Mag supplement
- Feed every other watering
Week 7–8 (Pre-Flowering):
- Switch to bloom nutrients (e.g., NPK 1-3-2 or 2-4-4)
- Add phosphorus/potassium boosters (PK 13-14)
Week 9–10 (Full Flower):
- Reduce nitrogen
- Increase potassium (e.g., NPK 0-3-6)
- Add bloom boosters
Week 11–12 (Flush):
- Only clean, pH-balanced water
- No nutrients
- Goal: remove salts and enhance bud flavor
Key Tips:
- Always follow the feeding chart with a TDS or EC meter
- Overfeeding causes root burn and salt buildup
- Use clean, filtered water with proper pH
- Watch your plants for signs of over/underfeeding
Conclusion
Mastering nutrient feeding is essential for top-shelf cannabis. Matching your feed to the plant’s growth stage, using the right NPK ratio, and monitoring plant responses will maximize both yield and quality.