Boston Fern Fronds Turning Oily Brown Near Window: Soft Rot

The Symptom

Half the fern (nearest window) became dark brown, oily, odorous within a week. Winter, low light.

Cause

Soft rot. Fronds touching cold window → poor air circulation + condensation + warmth → bacterial/fungal rot.

Fix

• Keep foliage off window glass.
• Improve air movement around plant.
• Trim rotted fronds.
• Water less in winter.