Orchid Blooms Rotting: Black Spots, Curling Edges—Hard Water and Fertilizer Issues

Question:

New to this. Orchid blooms (not leaves) turning spotty, black edges, curling, falling off. Buy at Lowe's/Home Depot sale rack, nurse back. Bloomed recently after long period, now spots/black edges after ~2 months. Normal?

Answer:

Hello Barbara,

Didn't mention orchid types, but general causes:

Black spots on leaves: common in thin-leaved orchids. Usually water droplets left overnight → fungus. Mist in morning so evaporation before night. Light air movement helps.

Black leaf edges: usually hard water (high salts) or excess fertilizer (or both). Especially true for thin-leaved orchids.

Summary: water/mist in morning; if hard water, use bottled water; if fertilizing, cut to ~½ label rate.

Jim Kawasaki
San Jose, CA