How to Save a Plant from Root Rot (Step-by-Step)

Root rot is the most common cause of houseplant death — and the most preventable. It's caused by fungi (Pythium, Phytophthora, Fusarium) that thrive in waterlogged, oxygen-starved soil. The good news: if you catch it early, you can save the plant. Here's exactly how.

How to Tell If Your Plant Has Root Rot

Above-ground symptoms:

• Leaves yellowing suddenly, especially lower leaves
• Wilting even when the soil is wet (the roots can't take up water)
• Brown mushy stem at the base
• A foul, musty or sour smell from the soil
• Soil that stays wet for weeks without drying

Confirming it: Take the plant out of its pot. Healthy roots are white or cream-coloured and firm. Rotted roots are brown or black, slimy, and smell bad. They break apart easily when touched.

If you see any rotted roots, act immediately.

What You'll Need

• Sharp, clean scissors or pruning shears
• Isopropyl alcohol (70%) to sterilise tools
• Activated charcoal (optional but helpful)
• Fresh well-draining potting mix
• A clean pot with drainage holes
• Hydrogen peroxide 3% solution (optional)
• A towel

Step-by-Step Rescue Guide

Step 1: Remove the Plant from Its Pot

Gently slide the plant out. If it's stuck, run a knife around the inside edge of the pot. Don't yank by the stem — grip the base where it meets the soil.

Step 2: Rinse the Roots

Hold the root ball under room-temperature running water and gently wash away all the old soil. You need to see every root clearly to assess the damage.

Step 3: Inspect and Trim Rotted Roots

Sterilise your scissors with isopropyl alcohol. Trim every root that is:

• Brown or black in colour
• Soft or mushy when squeezed
• Hollow or stringy
• Smells bad

Cut back to healthy white tissue, making clean cuts. It's better to remove more than you think — any remaining rot will spread.

If more than 50% of the root system is rotted, the plant may not survive. You can try, but also take stem cuttings as insurance (see how to propagate from cuttings).

Step 4: Treat the Remaining Roots

Options:

• Hydrogen peroxide rinse: Dilute 3% H₂O₂ 1:3 with water. Dip the roots for 5 minutes, then rinse with plain water. This kills remaining fungal spores.
• Activated charcoal: Dust cut ends with activated charcoal powder — it's antimicrobial and helps prevent further rot.
• Cinnamon: A folk remedy with some evidence — dust cut root ends with ground cinnamon (natural antifungal).

Step 5: Let the Roots Air-Dry

Place the plant on a towel in a bright, airy spot for 1–2 hours. This lets the cut surfaces dry and callous slightly, reducing the chance of re-infection.

Step 6: Prepare Fresh Soil and a Clean Pot

Wash the old pot with diluted bleach solution (1:10) to kill any remaining fungal spores. Or use a new pot.

Prepare a well-draining mix:

• Standard potting soil: 60%
• Perlite: 30%
• Orchid bark or coarse sand: 10%

Do not reuse the old soil — it contains the rot-causing fungi.

Step 7: Repot

Place a layer of fresh mix in the bottom of the pot. Position the plant and fill around the roots, firming gently. Don't bury the base of the stem.

Step 8: First Watering After Root Rot

Wait 48 hours before watering. When you do water, add diluted hydrogen peroxide solution (1 tsp per litre of water) to the first two waterings — this oxygenates the soil and kills remaining fungal spores.

Recovery Expectations

• Minor root rot (under 25%): Full recovery expected in 4–8 weeks
• Moderate root rot (25–50%): Plant may recover but expect some leaf drop during stress
• Severe root rot (over 50%): Recovery is possible but not guaranteed; take cuttings immediately as backup

The plant will look rough for a few weeks. Resist the urge to fertilise (it stresses damaged roots) or to overwater in sympathy. Just let it recover.

Preventing Root Rot

1. Always use pots with drainage holes
2. Never let plants sit in saucers of standing water
3. Use well-draining soil — add perlite to standard mixes
4. Check soil moisture before every watering (don't water on a schedule)
5. Reduce watering in winter by 30–50%
6. In doubt, wait another week

Also see: Why Are My Plant Leaves Turning Yellow? — overwatering causes yellowing before rot sets in.