Can be caused by:
• Improper/low pH
• Nutrient Lockout
• Phosphorus, Potassium or Magnesium Toxicity
• VPD out of range
For Coco: Ensure Coco has been buffered with Ca/Mg. Without buffering, Ca and Mg deficiencies are more likely to occur.
Organic Solutions:
• Egg Shells. When crushed in soil, it will a be a slower release. However, crushed egg shelled, warmed up, mixed with vinegar (1:10) as a foliar spray will be a much quicker way for your plant to recieve calcium
• Dolomite Lime
• Organical Magic by Future Harvest
Inorganic Solutions:
• CalMag Supplements
• Calcium Nitrate
* Affected leaves usually do not recover from damage even after correcting the problem. *