Barrel Cactus Decline: Light Deficiency and Rot Risk in Indoor Specimen

Case: Large Barrel Cactus Yellowing and Softening

12" diameter × 14" tall barrel cactus, previously 10 years in store window, now shows basal yellowing and unilateral "melting" after 6 months low light (east exposure, cold winter). Monthly watering regimen.

Primary Suspect: Insufficient Light

• Etiolation weakens tissue structure
• Reduced photosynthesis = reduced defense compounds
• Cool temperatures + low light = rot susceptibility
• Store window provided ideal conditions previously

Immediate Actions

1. STOP WATERING: If rot suspected, water accelerates spread
2. Light rehabilitation: Gradual increase to brighter conditions
3. Summer outdoors? Only with afternoon shade & rain protection
4. Sunburn risk: Acclimate over weeks - current tissue vulnerable

Prognosis

Uncertain. May stabilize with light correction, but existing damage is permanent. "Melting" tissue unlikely to recover. Focus on preventing spread to healthy portions.