Phalaenopsis Yellowing Leaves: Root Rot Diagnosis and Repotting Fix

Three-Week-Old Plant, Two Leaves Lost

Bottom leaf yellowed/wilted/dropped. Third leaf now half-yellow, had black spot at purchase. Bathroom, bright indirect light, watering every 1.5–2 weeks, no fertilizer yet.

Root Rot Is the Probable Cause

Yellowing lower leaves + black spot history = root system failure. The plant likely arrived with compromised roots.

Immediate Action Plan

1. Let current blooms finish.
2. Unpot, rinse roots thoroughly.
3. Remove ALL mushy/stringy roots (healthy = firm, green when wet).
4. Repot in fresh, pre-soaked orchid mix (bark, perlite, charcoal).
5. Clear plastic pot with ample drainage.
6. Wait 1 week before watering; then water when mix nearly dry.
7. Fertilize at ¼ strength only after new roots appear.

Fertilizer Recommendation

Any balanced fertilizer (20-20-20, 10-10-10) at ¼ label concentration. Or dedicated orchid formula.

Prognosis

High chance of recovery if healthy roots remain. Root regeneration precedes leaf regeneration. Patience required.