The leaves on a plant turn yellow primarily because something is interfering with the plant's chlorophyll, which gives leaves their green color. The most common causes include:
- Improper watering: Both overwatering and underwatering are leading reasons. Overwatering causes roots to suffocate due to lack of oxygen, leading to yellow leaves starting at the bottom and possibly root rot. Underwatering causes stress and leaf yellowing due to moisture deficiency.
- Nutrient deficiencies: Lack of essential nutrients like nitrogen, potassium, magnesium, iron, or sulfur causes different patterns of yellowing on leaves depending on the nutrient lacking. For example, nitrogen deficiency causes general yellowing starting from older leaves, iron deficiency affects young leaves.
- Poor soil conditions: Inappropriate soil pH can block nutrient uptake, leading to yellow leaves due to nutrient lockout.
- Root damage or the plant being root bound can reduce water and nutrient uptake, causing yellow leaves.
- Pests and diseases feeding on plant sap can also cause yellowing.
To fix yellow leaves, it helps to check watering habits (ensure soil drains well and don't water too often or too little), fertilize appropriately, inspect soil pH, and look for pests or root issues.
