Cannabis Nutrients and Feeding Guide: How to Properly Feed Your Plants

Table of Contents

• Key Takeaways
• 1. Introduction
• 2. Understanding Essential Cannabis Nutrients
• 3. Macronutrients: N-P-K Explained
• 4. Micronutrients and Their Role
• 5. Organic vs. Synthetic Fertilizers: Which is Best?
• 6. Feeding Cannabis in Different Growth Stages
• 7. How to Avoid Overfeeding and Nutrient Burn
• 8. pH and Nutrient Absorption
• 9. Common Nutrient Deficiencies and How to Fix Them
• 10. Frequently Asked Questions
• 11. Conclusion

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Key Takeaways

• Cannabis plants need three main macronutrients: Nitrogen (N), Phosphorus (P), and Potassium (K).
• Organic vs. Synthetic Nutrients: Organic nutrients build soil health, while synthetic nutrients provide faster absorption.
• Each growth stage requires different feeding: More nitrogen during vegetation more phosphorus, and potassium during flowering.
• pH levels must be balanced to ensure proper nutrient absorption (5.8–6.5 for soil, 5.5–6.2 for hydroponics).
• Nutrient deficiencies can stunt growth—watch for yellowing leaves, curling tips, or purple stems.

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1. Introduction

Feeding your cannabis plants the right nutrients is essential for healthy growth, strong stems, and high yields. However, too much or too little can cause problems like nutrient burn, deficiencies, or stunted growth.

This guide will break down:
✔ Macronutrients and micronutrients cannabis plants need.
✔ How to feed plants during each growth stage (vegetative vs. flowering).
✔ How to balance pH for proper nutrient absorption.

Whether you’re using organic compost, bottled nutrients, or hydroponic solutions, this guide will help you optimize your cannabis feeding schedule.

2. Understanding Essential Cannabis Nutrients

Cannabis plants absorb nutrients through their roots, and every nutrient plays a vital role in photosynthesis, cell development, and bud production.

There are three categories of nutrients:
✔ Macronutrients – The primary elements required for plant growth.
✔ Micronutrients – Essential trace elements in smaller amounts.
✔ Secondary Nutrients – Additional elements that improve plant health.

3. Macronutrients: N-P-K Explained

Macronutrients are the three main building blocks of cannabis growth.

💡 Tip: The nutrient ratio on fertilizers is displayed as N-P-K. For example, a 10-5-5 fertilizer contains 10% nitrogen, 5% phosphorus, and 5% potassium.

4. Micronutrients and Their Role

Cannabis also needs small amounts of micronutrients to stay healthy.

💡 Tip: Calcium and Magnesium are commonly added together in Cal-Mag supplements for optimal plant health.

5. Organic vs. Synthetic Fertilizers: Which is Best?

There are two types of fertilizers used for cannabis cultivation:

💡 Tip: If growing in soil, organic nutrients help maintain microbial life. If using hydroponics or coco coir, synthetic nutrients are more effective.

6. Feeding Cannabis in Different Growth Stages

Cannabis plants require different nutrients at each stage.

1. Seedling Stage (First 2 Weeks)

✔ Minimal nutrients needed—overfeeding can burn young plants.
✔ Water with pH-balanced water only until the first true leaves appear.

2. Vegetative Stage (Weeks 3–8)

✔ High Nitrogen (N) levels for strong leaf and stem development.
✔ Example N-P-K ratio: 10-5-5 or 20-10-10.
✔ Watering frequency: Every 2–3 days, depending on soil dryness.

3. Flowering Stage (Weeks 8–12)

✔ Reduce Nitrogen and increase Phosphorus (P) and Potassium (K) for bigger buds.
✔ Example N-P-K ratio: 5-10-10 or 4-8-8.
✔ Watering frequency: Adjusting based on soil moisture every 2–4 days.

7. How to Avoid Overfeeding and Nutrient Burn

❌ Symptoms of Overfeeding:

• Dark green, clawed leaves
• Burnt leaf tips (nutrient burn)
• Nutrient buildup on soil (white salt deposits)

✅ How to Fix It:
✔ Flush your plants with pH-balanced water to remove excess nutrients.
✔ Reduce feeding to half-strength nutrients and monitor recovery.

8. pH and Nutrient Absorption

pH is critical for nutrient absorption. Nutrients become locked out if the pH is too high or too low, and plants can’t absorb them.

💡 Tip: Use a pH meter and adjust with pH Up/Down solutions if needed.

9. Common Nutrient Deficiencies and How to Fix Them

Deficiencies often appear as leaf discoloration, spots, or stunted growth.

10. Frequently Asked Questions

Q: Can I use regular garden fertilizer for cannabis?
A: No, cannabis requires specific N-P-K ratios that differ from standard garden plants.

Q: How often should I feed my plants?
A: Generally, 1–2 times per week, depending on plant needs and soil quality.

Q: Should I flush my plants before harvest?
A: Flushing with plain water 1–2 weeks before harvest removes excess nutrients, improving taste.

11. Conclusion

Proper nutrient management is key to growing strong, healthy cannabis plants with big, potent buds.

✔ Feed high nitrogen (N) in vegetative growth.
✔ Boost phosphorus (P) and potassium (K) during flowering.
✔ Monitor pH for nutrient absorption and prevent deficiencies.

Next, learn about grow lights and how to optimize lighting for cannabis!