Diagnosing Yellowing Citrus in Arizona: Fertilizer, Drainage, and pH

Yellowing citrus leaves in hot climates often signal nitrogen deficiency, but water management and soil pH are equally critical.

Fertilizer Schedule

• Feed every 3 months (3–4×/year) on a fixed schedule—not just when problems appear.
• Use 2:1:1 or 3:1:1 ratio fertilizers (e.g., 20-10-10, 29-14-14, 10-4-6).
• Prefer acidifying formulas like Miracid or Espoma Citrus-tone.

Critical Checks

1. Soil pH: Citrus needs 5.5–6.5. Test first—high pH locks up nutrients.
2. Drainage: Heavy clay or poor drainage causes yellowing regardless of fertilizer. Consider raised beds or soil amendment.
3. Watering: Daily light watering encourages shallow roots. Water deeply, less often.

Stress Factors

Aphids, irregular feeding, and transplant shock compound problems. Address root causes before adding more fertilizer to stressed trees.

Tea Leaves Note

Used tea leaves break down slowly and may temporarily tie up nitrogen. Not a primary cause, but compost them first.