rhizome rot on Calathea
Quick answer
If your Calathea has rhizome rot, the most likely cause is: Calathea rhizome rot occurs when the fleshy underground stems are subjected to anaerobic conditions from waterlogged soil, typically from oversized pots, heavy moisture-retentive soil mixes, or watering before the top 2 inches of soil have dried. Pythium and Phytophthora pathogens thrive in saturated soil, attacking the carbohydrate-storing rhizomes that Calatheas rely on for water storage and new growth. Early signs include translucent, limp leaves and soft, squishy stems at the soil line—distinct from transplant shock which shows crisp edges and no foul soil odor.
Start here:
- 1. Unpot the plant immediately and inspect rhizomes—healthy tissue is white/firm, rotten rhizomes are brown/black, mushy, and may smell foul
- 2. Trim all rotted rhizome sections with sterile shears until only firm, white tissue remains
Why Calathea gets rhizome rot
Goeppertia spp.
Calathea rhizome rot occurs when the fleshy underground stems are subjected to anaerobic conditions from waterlogged soil, typically from oversized pots, heavy moisture-retentive soil mixes, or watering before the top 2 inches of soil have dried. Pythium and Phytophthora pathogens thrive in saturated soil, attacking the carbohydrate-storing rhizomes that Calatheas rely on for water storage and new growth. Early signs include translucent, limp leaves and soft, squishy stems at the soil line—distinct from transplant shock which shows crisp edges and no foul soil odor.
How to reverse rhizome rot on Calathea
- 1
Unpot the plant immediately and inspect rhizomes—healthy tissue is white/firm, rotten rhizomes are brown/black, mushy, and may smell foul
- 2
Trim all rotted rhizome sections with sterile shears until only firm, white tissue remains
- 3
Spray remaining healthy rhizomes with 3% hydrogen peroxide solution to disinfect cut surfaces
- 4
Allow rhizomes to callus (dry) for 2-4 hours before repotting to prevent secondary infection
- 5
Repot in fresh, dry well-draining mix (peat/perlite/orchid bark in 40:30:30 ratio)
- 6
Withhold water for 5-7 days post-repotting to allow wounds to heal
- 7
Resume watering only when top 2 inches of new soil are dry—use a moisture meter for accuracy
- 8
If rot is advanced, propagate healthy rhizome sections in water after hydrogen peroxide treatment
Keep rhizome rot off this Calathea
Use well-draining aroid mix (40-50% perlite/orchid bark) and appropriately sized pots (only 1-2 inches larger than root ball). Water only when top 2 inches of soil are dry—typically every 7-10 days depending on humidity. Ensure pots have drainage holes and discard excess water from saucers within 30 minutes.