Old Corn Plant (Dracaena fragrans) Decline: Alkaline Water, Repotting, and Light Change

Craig's 9-ft, 20-yr corn plant in Houston: repotted from 24" to 30" pot months ago. Declining since acquisition (not post-repot). New top growth healthy but slow; older leaves brown tips/edges. North-facing porch (indirect light). Weekly 0.5 gal water, biweekly Peters fertilizer. High pH tap water.

Three Compounding Factors

1. Alkaline water: High pH → nutrient lockout (especially iron) → marginal burn, yellowing. Switch to filtered/distilled/rainwater.
2. Light change: Previous light unknown. Any significant shift causes lower leaf loss.
3. Overpotting: 30" pot for 9-ft plant = excess wet soil → root stress. Repotting rarely helps ailing plants.

Immediate Actions

• Stop fertilizing until healthy (nutrients unavailable at high pH anyway).
• Use pure water only.
• Check root moisture: don't let bottom stay soggy.
• Target soil pH 6.0–6.8 (peat-based mix helps).

Likely Combination

No single cause — alkaline water + light shift + oversized pot = decline. Fix water first; monitor.