White Crust on Potted Citrus: Salt or Mold?

White dust on potting soil is either mineral salts (hard water) or powdery mildew (overwatering).

Diagnosis

• Crystalline, dissolves in water → salts. Use distilled/rain water.
• Fuzzy, filamentous → mildew. Reduce watering; improve air flow.

Citrus Care Basics

• Full sun (6+ hours).
• Water deeply only when top 2 inches dry.
• Ensure drainage; elevate pot.
• Mist with diluted bleach (4–5 drops/12 oz) for mildew.

Citrus hates wet feet and low light.