How to Revive a Houseplant with Root Rot | Signs Before Unpotting, Root Color and Firmness, and Rescue by Plant

Conclusion: Can a houseplant recover from root rot?

A houseplant with root rot can recover if white, firm roots remain. Cut off the black, soft roots and replant in fresh soil and a clean pot.

Root rot (roots dying and turning brown to black and soft) is the most common failure with indoor plants. U.S. university extension services and Japanese gardening manufacturers alike name overwatering as the cause.

The usual treatment follows these steps.

• Stop watering
• Take the plant out of the pot and look at the roots
• Cut off the damaged roots
• Replant in fresh soil

The hard part is knowing how far to cut, whether it really is root rot, and whether the plant can be saved. Here is the key point. Whether the plant can be saved depends on how firm the roots and trunk are, not on the leaves.

This article covers the following, in order.

• Signs you can spot before taking the plant out of the pot
• How to read root color and firmness once the plant is out
• Revival steps (where to cut, disinfecting, soil, pot and water)
• Judging whether the plant can be saved, and how to rescue it when almost no roots are left
• Differences by plant, winter care, and a checklist to prevent a relapse

How can you tell from the symptoms whether it is root rot?

Suspect root rot when the plant wilts even though the soil is wet. In the table below, the row "Wilting although soil is wet" is root rot.

Symptoms can overlap, so first find the row in the table closest to what you see. If the leaves are only turning yellow, also see Why Houseplant Leaves Turn Yellow.

If the plant is wilting but the soil is wet, do not add water; suspect the roots. The more water you add, the less oxygen the roots get, and the worse it becomes.

What signs show root rot before you take the plant out of the pot?

You can spot houseplant root rot through five signs even before unpotting. They include soil that stays wet, wilting in wet soil, and a soft base.

A University of Wisconsin resource puts it this way. Root rot is often first noticed when a plant wilts even though the soil is wet.

These are the signs to check before unpotting.

• The leaves or stems wilt even though the soil is wet
• The soil stays wet for days
• Lower leaves turn yellow first and drop one after another
• The base or trunk feels squishy and soft when pressed
• Small insects (fungus gnats) fly over the soil surface

For pachira, a Hyponex guide says this. If the trunk feels squishy when pressed with a finger, root rot is possible. A healthy trunk is taut and stays firm.

Fungus gnats are small flies that multiply in wet soil. A Clemson University resource says their larvae can feed on roots and that overwatering makes them multiply.

Underwatering is easy to confuse with root rot. In both cases the leaves wilt and the lower leaves turn yellow.

Tell them apart by the soil, not the leaves. Push a finger in up to the second knuckle to check.

How do you tell by the color and firmness of the roots once the plant is out?

Healthy roots are white to light in color and firm; rotted roots are brown to black and soft. When pulled, only the outer skin slides off, leaving the inner core like a thread.

A Clemson University resource describes rotted roots as "brown to black, and may be soft." A University of Maryland resource describes roots attacked by pathogens like this.

• The outer tissue peels off easily
• Only the central core is left

A University of Wisconsin resource says rotted roots "may have a bad smell." If you notice a nasty smell as you shake off the soil, suspect root rot.

Decide where to cut by both color and firmness. Do not go by color alone; pinch the roots and cut the ones that squash softly.

Why does root rot happen in houseplants?

Houseplant root rot happens when the soil stays wet, the roots cannot breathe, and pathogens in the soil get in. Overwatering is the trigger.

A Hyponex guide explains it like this. When overwatering keeps the roots constantly sitting in water, they cannot breathe, and root rot sets in.

Clemson University and University of Wisconsin resources name the pathogens responsible. They include Pythium, Phytophthora and Rhizoctonia.

These pathogens survive in soil and dead plant matter. They multiply more easily when there is a lot of water.

Watering too often is not the only reason the soil stays wet.

• The pot is too big for the amount of roots
• The pot has no drainage hole, or water collects in the saucer
• Old soil has packed down like clay and does not drain
• A plastic or decorative pot keeps the soil from drying
• In winter, growth stops and the plant takes up little water

A University of Illinois resource says a pot that is too big can lead to root rot. A Hyponex guide says soil used for a long time turns clay-like and drains poorly.

Here is the key point. Even if you keep to a sensible watering schedule, root rot can happen if the pot and soil cannot dry out. The section on preventing a relapse covers how to review the pot and soil.

How do you revive a houseplant with root rot?

To treat houseplant root rot, stop watering, check the roots and cut off the damaged ones. Then replant in fresh soil and a clean pot.

A Clemson University resource describes the treatment like this. If only a few roots are damaged, cut them off and repot in sterilized soil.

A Hyponex guide follows the same steps. Remove the rotten parts, rinse, and plant in well-draining soil. Give no fertilizer until the roots take hold.

As steps, it looks like this.

1. Stop watering and put the plant in bright shade with good airflow
2. Take the plant out of the pot. If it sticks, tap the rim of the pot lightly
3. Loosen the old soil by hand and shake it off. Rinse with water if needed
4. Cut off roots that squash when pinched, back to just before the firm roots
5. Disinfect the shears after each plant
6. Prepare a pot sized to the amount of roots, and fresh soil
7. Plant at the same depth as before, and water until it runs out of the bottom of the pot
8. Keep it in bright shade, and water again only after the soil has dried

Here are the tools and materials.

Right after planting, water thoroughly once; after that, water only once a finger test shows the soil is dry. Plants with root rot were damaged by the habit of watering again before the soil dried. The important thing is not to fall back into that habit.

Sansevieria is the exception. A Hyponex guide says that after the watering right after planting, no water is needed for 1 to 2 weeks.

How many days should you dry the roots after cutting?

Most of the sources we checked do not call for drying the roots for days. After cutting off the damaged roots, you plant in fresh soil and water.

Online, you will also see advice to "dry the roots for a few days." However, the university and manufacturer sources checked for this article gave no set number of days.

The only drying times we found were for cut surfaces of succulent plants. A Hyponex guide to sansevieria says this.

• Offshoots from division: dry the cut surface for half a day to 1 day before planting
• Leaf cuttings: dry the cut surface in the shade for a few days to 1 week before inserting

Here is the key point. What you dry is the soil, not the roots. Stopping water and letting the soil dry before unpotting also makes the work easier.

For non-succulent plants such as monstera and pothos, the sources give no step for drying the roots. After cutting, plant straight into fresh soil.

Where do you judge whether a houseplant with root rot can be saved?

Judge it by how many white, firm roots remain and how firm the trunk or stems are. If new shoots are growing, the chances are better.

U.S. university resources draw the line clearly.

• If only a few roots are damaged, cut them off and repot (Clemson University)
• If most roots are black, soft and dead, it is better to discard the plant (Clemson University)
• Discarding a plant with root rot is the least costly option (University of Wisconsin)

A houseplant at home is often a much-loved pot. Before throwing it out, there is a way to keep the parts that can be saved.

A Hyponex guide to pachira says this. Once root rot sets in, the plant will not go back to how it was, but if it is not severe, healthy roots may grow back.

"No roots" does not mean "game over." If green, firm stems remain, you can grow a new plant from cuttings.

How do you save a plant with almost no roots left?

Take cuttings from green, firm stems or leaves and grow a new plant. How long to cut and how many days roots take differ by plant.

Taking cuttings means cutting a stem or leaf and putting it in soil or water so it grows roots. Gardening manufacturers' guides give the method for each plant.

All of these come from Hyponex guides. For every one of them, the best time for cuttings is the warm season from May to September.

Stay away from the rotten part and choose the firmest, best-colored section. If the cut surface is brown and soft, cut again higher up until a green, firm cross-section appears.

Does root rot show differently in monstera, pachira, pothos, Ficus microcarpa and sansevieria?

Yes. Houseplant root rot first shows in different places depending on the plant, and how far to cut back water differs too.

With the same root rot, it shows in the trunk first on pachira and at the leaf bases on sansevieria. We sorted out the differences among the five plants using manufacturers' growing guides.

Sansevieria needs less water than the other four. A Hyponex guide says it goes dormant in winter, and once it drops below 10°C you should not water at all.

Source: Hyponex Plantia care guides, RHS hardiness ratings, ASPCA toxic plant list

With sansevieria root rot, watering less often is half the treatment. It stores water in its leaves, so once the roots weaken, it cannot take up all the water in the soil.

Lining up the five plants' watering and winter needs shows why you should not water them all on the same schedule.

Source: Hyponex Plantia care guides, RHS hardiness ratings, ASPCA toxic plant list

What should you do if you find houseplant root rot in winter?

In winter, if it is mild, stop watering, let it dry and wait for spring. Do only a minimal replanting if the soil will not dry, there is a rotten smell, or the base is soft.

Winter is when root rot is most likely. A Hyponex guide to overwintering also says that most winter plant losses come down to watering problems.

On the other hand, winter is also a poor time to repot. A Clemson University resource says weakened or dormant plants should not be repotted.

So, split it by how severe the symptoms are.

After winter treatment, keep the plant away from a cold window at night. Winter placement and how to cut back water are covered in Winter Care for Houseplants.

In winter, adding water or fertilizer to "help it recover" backfires. Growth starts again in spring.

How do you keep root rot from coming back?

Review three things: the pot, the soil and the watering. Plants with root rot were almost always set up so that water went in before the soil had dried.

A University of Wisconsin resource stresses that if you keep a plant that had root rot, you must "reduce soil moisture." So it does not dry out too far, give only as much water as it needs.

Soil mixes are covered in Choosing Soil for Houseplants. Timing and choosing a pot are covered in When to Repot Houseplants.

What works best is the habit of pushing a finger into the soil every time before you water. Even with the right pot and soil, the same thing happens if water goes in before the soil dries.

What terms come up when talking about houseplant root rot?

What else should you know along with houseplant root rot?

Houseplant root rot is linked to yellow leaves, repotting, soil and overwintering. Go on to the next article based on where the symptom showed up.

• Yellow lower leaves: Why Houseplant Leaves Turn Yellow
• Only the leaf tips are brown: Why Houseplant Leaf Tips Turn Brown
• When to replant and how to choose a pot: When to Repot Houseplants
• Well-draining soil: Choosing Soil for Houseplants
• Water and placement in winter: Winter Care for Houseplants

Frequently asked questions about houseplant root rot

Can a plant with rotted roots recover?

If white, firm roots remain, it can recover. Cut off the black, soft roots and replant in fresh soil.

If most of the roots are black and soft, recovery from the roots is hard. If green, firm stems remain, you can grow a new plant from cuttings.

How many days should you dry out root rot?

There is no set number of days. Drying the soil matters more than drying the roots outside the pot.

For mild root rot, stop watering and wait for the soil to dry all the way through. Growth slows in winter, so drying takes longer.

If you cut the roots and replanted, water thoroughly once right after planting. After that, water again only once the soil is dry about 3 cm down, checked with a finger. Do not water sansevieria for 1 to 2 weeks after planting.

What if root rot has gone too far?

If the trunk or base is soft, recovery from the roots is unlikely. Cut green, firm stems from higher up and root them as cuttings in soil or water.

For pachira, stand 10 to 15 cm from the tip in water, and roots appear in 10 days to 2 weeks. If the cut surface is brown, cut again until a green cross-section appears.

What should you do about houseplant root rot?

First, stop watering. Next, unpot the plant, look at the roots, cut off only the damaged ones, and replant in fresh soil.

Add fertilizer to a plant with root rot only after the roots take hold. Fertilizer salts touching weak roots damage them further.

What does root rot smell like?

Rotted roots can smell rotten. Healthy roots smell of nothing but soil.

A University of Wisconsin resource also says rotted roots "may have a bad smell." Smell is a supporting clue; the deciding factors are root color and firmness.

Can you reuse the soil or pot after root rot?

Do not reuse the soil. The pathogens that cause root rot survive in soil and dead roots.

If you reuse the pot, scrub it and rinse it with bleach diluted 10 times with water (Clemson University). Some sources recommend throwing out plastic pots (University of Wisconsin).

Sources

• Clemson University HGIC: Houseplant Diseases & Disorders (symptoms of root rot, the pathogens, cutting back and repotting, discarding plants that are mostly dead, disinfecting pots)
• Clemson University HGIC: Indoor Plants: Transplanting & Repotting (pot size, the gravel layer at the bottom, not repotting weak plants)
• Clemson University HGIC: Common Houseplant Insects & Related Pests (fungus gnat larvae and overwatering)
• University of Wisconsin-Madison Extension: Root Rots on Houseplants (wilting in wet soil, root color and smell, the pathogens, handling the pot)
• University of Maryland Extension: Root, Crown, and Stem Rots on Flowers (the outer tissue sloughs off and leaves the core)
• University of Maryland Extension: Pruning Tools (disinfecting with 70% alcohol or bleach diluted 1 to 9)
• University of Nebraska-Lincoln Extension: Success With Houseplants - Fertilization (do not fertilize wilting or unrooted plants; salts damage roots)
• University of Illinois Extension: Tips for Repotting Houseplants (oversized pots and root rot, pots without holes)
• Hyponex Plantia: Why is your houseplant not thriving? What is the cause? (in Japanese. Causes of root rot and recovery by repotting)
• Hyponex Plantia: What is the recommended soil for houseplants to grow healthily? (in Japanese. Drainage of old soil)
• Hyponex Plantia: How to care for Pachira | Is watering the reason it dies? (in Japanese. Soft trunk, rooting in water)
• Hyponex Plantia: How to care for Pothos (in Japanese. Cuttings, rooting in water)
• Hyponex Plantia: How to care for Monstera (in Japanese. Repotting, cuttings)
• Hyponex Plantia: How to care for Ficus microcarpa (in Japanese. Root care, cuttings)
• Hyponex Plantia: How to care for Sansevieria and repotting methods (in Japanese. Watering after repotting, division, leaf cuttings)
• Hyponex Plantia: 18 cold-hardy houseplants and key points for overwintering (in Japanese)
• KINCHO Engei: Types of containers (in Japanese. Pot materials and how fast they dry)