How To Identify, Fight And Prevent Root Rot

Root rot occurs as wet soil conditions lead to fungal infection and the decay of a plant. Low oxygen levels in the water-logged soil promote fungus growth. The infection spreads from the roots to the entire plant. Potted plants are at a greater risk than garden plants, and develop mushy roots with wilting, yellow leaves. Left untreated, the plant eventually dies. If root rot is suspected, it’s important to act immediately!

How to Treat Root Rot

In today’s chat, we will provide you with a step-by-step guide on how to treat root rot and tips on how to identify it. Our focus here at the Garden Bench Top is on prevention as the best way to avoid root rot.

Grab a coffee, put your feet up and let’s get started!

What is Root Rot?

Root rot is the general term for phytophthora root rot (Phytophthora spp.) This disease attacks the roots of plants growing in soggy soil. Plant roots need air and oxygen for nutrient and water absorption. Excess moisture in the soil leads to low oxygen levels, and fungal growth. Soil becomes infected with fungi such as Pythium, Phytophthora, Rhizoctonia, and Fusarium. Faced with the onslaught of a fungal infection and a lack of oxygen and water, the plant begins to die.

What Is The Main Cause Of Root Rot?

Main Cause of Root Rot

Overwatering and poor drainage are the big causes of root rot. Container plants have difficulty controlling moisture, so any excess water is a big problem. Prolonged immersion in wet potting soil places a healthy plant at risk of root rot. As the disease arises under the soil, many gardeners are unaware they even have a problem.

What does Root Rot look like (versus healthy roots)?

Healthy plant roots are distinguished by white or green roots that feel firm to the touch. Soil smells fresh and earthy.

In contrast, decaying roots are mushy in texture and dark brown in color. Infected soil also smells rotten and swampy.

root rot looks like decaying roots that are mushy and dark brown, with a rotting smell

Fungal spores attack the roots first, with damage below the surface, unseen. As the disease spreads up the plant, visible signs become evident – stunted growth, discoloration, and wilting leaves including dropping of leaves. Regretfully, by the time you detect an infection, a significant amount of injury has occurred and in extreme cases, the plant cannot be saved.

What does root rot look like

Symptoms Of Root Rot

These are signs of root rot:

  • Leaf damage – leaves wilt, turn yellow, and may drop off
  • Stunted plant growth – growth is stunted with delayed flowering
  • Root decay – roots that are dark brown, mushy, and have a musty odor.
  • Wet soil – infected roots lose their ability to absorb water and prompt fungal growth

How to Get Rid of Root Rot (Instruction Guide)

We highly recommend removing your plant from its container for inspection if there is any suspicion of root rot.

It’s essential to be gentle when handling your plant, so as not to cause any further damage to the weakened roots.

If all the roots are damaged, unfortunately, the plant cannot be saved. However, if there is still a remnant of healthy roots, we provide the following guide to treat the root rot and repot your plant.

  1. Carefully remove the root system from its pot and inspect the roots
  2. Gently loosen soil from around the roots without overly disturbing the root system.
  3. Wash the roots under water to remove all the old soil.
  4. With a hydrogen peroxide or bleach solution, wash the old pot and any gardening tools to kill pathogens and prevent the spread of fungal spores. The solution is made by mixing one part bleach with two parts water.
  5. Sterilize scissors with rubbing alcohol. Use scissors to cut off all of the brown, rotting roots. Keep as much of healthy portions as possible. Remember to re-sterilize your scissors after use.
  6. Pour fungicide solution over the remaining roots to kill root fungus and prevent regrowth. If you don’t have fungicide you can use the hydrogen peroxide solution (mix one part bleach with 15 parts water).
  7. Using the same ratio as the infected root removed; prune back the same proportion of the plant foliage. This will reduce the burden on the pruned, smaller root base to support the plant foliage.
  8. Pot your treated plant into a container with sufficient drainage holes. Use fresh soil that has good drainage properties. The new soil will permit the plant to absorb much-needed water and nutrients.

How To Avoid Root Rot?

credit: Unsplash

Don’t overwater!

Keep the potting mix as dry as possible. Use a moisture meter or do a simple soil moisture check – if the top 1.5 inches (3 centimeters) of soil are dry, it’s time to water.

Ensure proper drainage with adequate drainage holes in your pot and don’t allow your plant to sit in water.


At the Garden Bench Top, we love to place our houseplant containers into larger pots or on saucers, atop pebbles at the base. This ensures good airflow and prevents waterlogged soil.

Common Questions

Can a plant recover from Root Rot?

Sadly, if the entire root system is brown and mushy, the plant cannot be saved. If there are still some firm, white roots – the plant has a good chance of recovery. There is the risk that an already stressed plant may not survive the repotting process. However, root rot left untreated will kill your plant, so there is no option but to intervene. With tender love and care, we hope your plant pulls through!

What Is The Best Treatment For Root Rot?

Fungicides are effective in treating root rot in houseplants. Many existing products on the market are harmful to other organisms and as such need careful, safe application. A more recent arrival is phosphonate fungicide. This is an ideal choice of ours! It has no harmful impacts, is relatively inexpensive, can be applied as a treatment, and also provides great protection in preventative use.

Can you treat root rot with hydrogen peroxide?

Hydrogen peroxide or bleach can be used to sterilize the soil and kill the fungus spores. As it is high in oxygen, it will also replenish the oxygen-depleted soil and promote root growth. Pour directly onto the root system, with a watering can. We also recommend washing your gardening tools, to kill any pathogens.

How long does it take for a plant to recover from root rot?

Evidence of recovery should be visible within one to two weeks. If the damage is more extensive and the portion of healthy roots minimal, the plant may take longer to recover.

Final Thoughts

Root rot is a serious problem for any gardener. If plant leaves are yellowing and wilting, and roots are brown and mushy, you need to take immediate action. The likely cause is overwatering and poor drainage. This leads to fungal growth and the inability of the plant to absorb water and nutrients. To treat root rot, remove the affected roots and repot the plant in fresh soil. Avoid overwatering and ensure good drainage. Equipped with this know-how, we hope you’ll be on top of root rot at your home.

Happy gardening!