Christmas Cactus Edema: Overwatering-Induced Corky Bumps

Diagnosis: Edema (Oedema)

Brown raised bumps (1mm–1cm), some scrapable = edema. Physiological disorder from roots absorbing water faster than leaves transpire. Triggered by sudden humidity increase in hot/dry conditions.

Correction

• Repot in peat-based mix + coarse sand/perlite (3:1 ratio).
• East window (bright, not scorching).
• Free-draining pot mandatory.
• Water only when top inch dry.

Key Insight

Not a pathogen—no contagion. Existing bumps permanent; new growth clean if conditions corrected.