Providing cannabis plants with the right nutrients is critical for their growth, health, and productivity. Nutrients are essential for photosynthesis, cell development, and overall plant function. This guide covers the types of nutrients, their roles, and how to measure and manage them effectively to optimize cannabis cultivation.
1. Types of Nutrients
Macronutrients
| Element |
Role |
Deficiency Symptoms |
| Nitrogen (N) |
Vital for vegetative growth; promotes leafy development. |
Yellowing leaves, slow growth. |
| Phosphorus (P) |
Crucial for root development and flowering. |
Dark, discolored leaves; stunted growth. |
| Potassium (K) |
Enhances overall plant health and disease resistance. |
Yellow or burnt leaf edges; weak stems. |
Micronutrients
| Element |
Role |
Deficiency Symptoms |
| Calcium (Ca) |
Strengthens cell walls and supports enzyme activity. |
Deformed new growth, weak stems. |
| Magnesium (Mg) |
Key component of chlorophyll for photosynthesis. |
Interveinal yellowing (chlorosis). |
| Iron (Fe) |
Vital for chlorophyll synthesis and electron transport. |
Yellowing of young leaves. |
2. Nutrient Delivery Methods
- Soil Growing:
- Use organic compost or pre-mixed fertilizers for slow-release feeding.
- Supplement with liquid fertilizers during growth phases.
- Hydroponics:
- Provide nutrients directly in the water solution.
- Monitor Electrical Conductivity (EC) and pH levels for optimal uptake.
3. Measuring Nutrient Levels
- Electrical Conductivity (EC):
- Measures the total concentration of nutrients in the solution.
- Ideal EC range for cannabis: 1.0–2.5 mS/cm, depending on growth stage.
- pH Levels:
- Controls nutrient availability to the plant.
- Optimal pH for soil: 6.0–6.5; for hydroponics: 5.5–6.5.
- Parts Per Million (PPM):
- Measures nutrient concentration in water.
- Recommended PPM ranges:
- Seedling stage: 100–250 PPM.
- Vegetative stage: 300–700 PPM.
- Flowering stage: 700–1,200 PPM.
4. Troubleshooting Nutrient Issues
- Overfeeding: Causes nutrient burn, characterized by browning leaf tips.
- Underfeeding: Leads to nutrient deficiencies and poor growth.
- pH Imbalance: Can cause nutrient lockout, preventing absorption.
5. Advanced Tips
- Flush the growing medium periodically to prevent salt buildup.
- Use Cal-Mag supplements to address common calcium and magnesium deficiencies.
- Choose fertilizers tailored for each growth phase (e.g., high nitrogen for vegetative, high phosphorus for flowering).