Fertilizer Burn on calathea
What's Happening
Calathea are extremely sensitive to fertilizer salts that accumulate in soil and cause osmotic stress, burning roots and leaf tips. Excess nitrogen causes rapid but weak growth susceptible to pests and disease. Salt buildup appears as white crust on soil surface and progresses to brown leaf tips. Unlike nutrient deficiency (uniform yellowing), burn affects newest growth first or appears as marginal necrosis. Water quality compounds the issue - hard water plus fertilizer creates dangerous mineral loads.
How to Fix It
- 1
Flush soil immediately with 3x pot volume of distilled water
- 2
Stop all fertilizing for 8-12 weeks
- 3
Trim affected leaf tips with sterile scissors
- 4
Repot in fresh soil if white salt crust visible
- 5
Resume feeding at 1/4 strength diluted fertilizer only during active growth
How to Prevent It
Use 1/4 strength balanced fertilizer monthly during spring-summer only. Never fertilize stressed or newly repotted plants. Flush soil every 2 months with distilled water to prevent salt accumulation.