Why is my Calathea getting root rot?

Calatheas get root rot almost always from overwatering that keeps the soil constantly soggy, which suffocates the roots until they decay. Poor drainage, dense soil and an oversized pot make it worse by holding water around the roots. The signs are mushy brown roots, a sour smell, and yellowing, drooping leaves. Unpot the plant, cut away the rotted roots, and repot into fresh, well-draining soil.

Most likely cause

Overwatering is the top cause of Calathea root rot. Calatheas like steady, light moisture but their roots need air, and soil that stays saturated starves them of oxygen. Without air the roots cannot function, opportunistic fungi move in, and the roots begin to decay.

You can confirm it by unpotting and checking. Healthy roots are firm and pale; rotted roots are brown or black, mushy, and fall apart when touched, often with a sour, swampy smell. Above the soil you will usually see yellowing, drooping leaves and soil that has stayed wet for days. If the soil is constantly soggy, rot is almost certainly underway. Caught early, cutting away the bad roots and repotting into airy soil lets the plant recover.

Other causes

These rank below overwatering but each keeps the roots wet longer than they can handle.

No drainage. A pot without holes, or a saucer left full, traps water at the bottom where roots sit and rot.
Dense soil. Heavy, water-retentive mix stays wet for days; the surface feels dry while the core is still soaked.
Oversized pot. A pot much larger than the root ball holds more wet soil than the roots can drink, so it stays soggy.
Cold temperatures. Cool conditions slow how fast soil dries and how much the plant drinks, leaving roots wet far longer.

How to fix it

Unpot and inspect. Slide the plant out and rinse the roots so you can see which are firm and which are mushy.
Cut away the rot. Use clean, sharp scissors to remove every soft, brown or black root back to healthy tissue.
Repot in fresh soil. Use a fresh, airy, well-draining mix in a pot with drainage holes that is only slightly larger than the root ball.
Empty the saucer. Never let the pot sit in standing water, and tip out any drained water after watering.
Water sparingly at first. Water lightly, then let the top inch dry before watering again so the surviving roots can recover.
Check moisture every time. Feel the top inch before watering rather than following a fixed schedule.
Keep it warm. Place the plant somewhere warm with steady temperatures so the soil dries at a normal pace.

Cause	Tell-tale sign	Fix
Overwatering	Constantly soggy soil, mushy roots	Let top inch dry, water only when needed
No drainage	Water pooling, full saucer	Use a pot with holes, empty the saucer
Dense soil	Surface dry, core still wet	Repot into airy, well-draining mix
Oversized pot	Soil stays wet for days	Size the pot to the root ball
Cold temperatures	Slow-drying soil, sluggish plant	Move somewhere warm and stable

Frequently asked questions

Can a Calathea recover from root rot?

Often, yes, if you catch it early. Unpot the plant, cut away all the mushy brown roots, and repot the healthy firm roots into fresh, well-draining soil. If nearly all the roots have rotted, recovery is unlikely, but you can try rooting a healthy division.

What does Calathea root rot look like?

Healthy Calathea roots are firm and pale; rotted roots are brown or black, mushy, and slip apart when touched, often with a sour smell. Above the soil you usually see yellowing, drooping leaves and soil that stays wet for days.

How do I treat root rot in a Calathea?

Unpot the plant and rinse the roots, then cut away every soft brown root with clean scissors. Repot into fresh, airy soil in a pot with drainage, water lightly, and let the top inch dry before watering again so the surviving roots can recover.

Does root rot smell?

Yes, often. Rotting roots and waterlogged soil give off a sour, musty, swampy smell. If your Calathea's soil smells bad and stays wet, that is a strong sign the roots are rotting and you should unpot and check them.

How often should I water a Calathea to avoid root rot?

Water only when the top inch of soil is just dry, rather than on a fixed schedule. Calatheas like steady, light moisture but never soggy soil, so always check with your finger first and make sure the pot drains freely.

Can the wrong pot cause Calathea root rot?

Yes. A pot with no drainage holes traps water at the bottom, and an oversized pot holds more wet soil than the roots can drink, both of which keep the roots soggy. Use a pot with drainage that is only slightly larger than the root ball.