Cannabis Nutrient Deficiencies: How to Spot, Stop, and Solve Common Problems

Understanding nutrient deficiencies is crucial for maintaining healthy cannabis plants. This comprehensive guide will help you identify, diagnose, and correct common nutrient issues before they seriously impact your grow.

The Essential Nutrients

Cannabis requires three primary nutrients (macronutrients):

• Nitrogen (N): Growth and leafy development
• Phosphorus (P): Root and flower development
• Potassium (K): Overall plant health and stress resistance

And several secondary nutrients:

• Calcium (Ca)
• Magnesium (Mg)
• Sulfur (S)

Common Deficiency Symptoms and Solutions

Nitrogen Deficiency

Signs:

• Yellowing of older leaves (bottom up)
• Accelerated leaf drop
• Slow growth
• Light green coloration

Solution:

• Add nitrogen-rich fertilizer
• Adjust pH to 6.0-7.0 for soil
• Consider organic amendments like blood meal

Phosphorus Deficiency

Signs:

• Dark green leaves turning purple
• Slow growth
• Weak stems
• Poor flower development

Solution:

• Add phosphorus-rich fertilizer
• Maintain soil temperature above 60°F
• Check pH levels (6.0-7.0 optimal)

Potassium Deficiency

Signs:

• Brown spots on leaves
• Curling leaf edges
• Yellow leaf margins
• Weak stems

Solution:

• Add potassium-rich nutrients
• Use compost tea
• Consider wood ash amendments

Advanced Nutrient Issues

Calcium Deficiency

Signs:

• New growth distorted
• Brown/dead spots on leaves
• Weak stems
• Stunted root growth

Solution:

• Add Cal-Mag supplement
• Check water quality
• Adjust pH if necessary

Magnesium Deficiency

Signs:

• Yellowing between leaf veins
• Older leaves affected first
• Leaf margins turning brown

Solution:

• Add Epsom salts
• Use Cal-Mag supplement
• Maintain proper pH levels

Prevention Is Better Than Cure

Best Practices

1. Regular Testing

   • Check pH levels daily
   • Monitor EC/PPM levels
   • Keep detailed nutrient logs

2. Proper Feeding Schedule

   • Start with 1/4 strength nutrients
   • Gradually increase as needed
   • Follow manufacturer guidelines

3. Water Quality

   • Use filtered water
   • Let chlorinated water sit 24 hours
   • Maintain proper temperature

Diagnostic Tips

The Process

1. Examine new growth first
2. Note which leaves are affected
3. Check if the problem is spreading
4. Review recent changes in feeding

Common Mistakes to Avoid

• Over-fertilizing
• Mixing incompatible nutrients
• Incorrect pH levels
• Poor drainage

Emergency Recovery Plan

If you spot deficiency signs:

1. Test pH immediately
2. Check runoff EC/PPM
3. Flush if necessary
4. Apply correct nutrients
5. Monitor closely for 48 hours

Conclusion

Nutrient deficiencies can be scary, but they're manageable with proper knowledge and quick action. Remember: a healthy plant is more resistant to deficiencies, so focus on prevention through proper care and monitoring.

Need help choosing the right nutrients? Check out our comprehensive guide to cannabis fertilizers in our next post.