24. Nutrient Deficiencies and How to Fix Them

Nutrient Deficiencies and How to Fix Them

Cannabis plants show clear signs when nutrients are lacking, and recognizing deficiencies early is key to restoring plant health and achieving high yields.

Common Deficiencies and Symptoms

1. Nitrogen Deficiency
   • Symptoms: Yellowing leaves starting from the bottom of the plant, stunted growth.
   • Fix: Apply a balanced nutrient solution with a higher nitrogen ratio.
2. Phosphorus Deficiency
   • Symptoms: Dark or purple stems, slow growth, and smaller leaves.
   • Fix: Use a bloom booster or supplement high in phosphorus, especially during flowering.
3. Potassium Deficiency
   • Symptoms: Yellow or brown leaf edges, weak stems, and spots on leaves.
   • Fix: Add potassium-specific nutrients or supplements.
4. Calcium Deficiency
   • Symptoms: Brown spots, curling leaves, and weak stems.
   • Fix: Use calcium-rich supplements like Cal-Mag.
5. Magnesium Deficiency
   • Symptoms: Yellowing between leaf veins, especially on older leaves.
   • Fix: Add Epsom salts or magnesium supplements to your feeding schedule.
6. Iron Deficiency
   • Symptoms: Yellowing of new leaves while veins remain green.
   • Fix: Adjust pH levels and use an iron supplement.

How to Diagnose Nutrient Deficiencies

• Check pH Levels: Nutrient uptake depends on maintaining the correct pH. Test pH regularly to prevent nutrient lockout.
• Observe Growth Stages: Nutrient needs change from vegetative to flowering stages, so adjust your feed accordingly.
• Identify Patterns: Nutrient deficiencies often appear on specific parts of the plant. Lower leaf issues indicate mobile nutrient deficiencies (like nitrogen), while new growth issues can signal immobile nutrient problems (like iron).

Preventing Nutrient Deficiencies

1. Balanced Nutrient Schedule: Follow a feeding plan tailored to cannabis needs, ensuring a balanced N-P-K ratio and adding micronutrients as needed.
2. Flush Regularly: Every few weeks, flush your grow medium to remove salt buildup and prevent lockouts.
3. Monitor Environmental Conditions: Temperature, humidity, and light intensity can all impact nutrient uptake.

Conclusion

Learning to identify and treat nutrient deficiencies will help you keep your cannabis plants healthy and thriving. With consistent monitoring and responsive adjustments, you can avoid setbacks and ensure optimal growth.