How to Identify and Treat Root Rot in Houseplants

Is your houseplant plant wilting, displaying yellow leaves, or relentlessly dropping its leaves no matter what you do? Root rot may be the culprit. Root rot is usually the result of plants being overwatered. So before you do anything else, set down your watering can, back away slowly, and read on for our top tips on what root rot looks like and how to treat root rot in houseplants. 

What Is Root Rot?

Root rot is a disease that affects the roots of plants and causes them to rot. It is caused by prolonged exposure to wet soil conditions and has two sources.

First, overwatered conditions can starve a plant's roots of oxygen, which causes them to rot and die. This rot can spread to all of the roots quickly and may persist even after the soil conditions have been corrected. The second source of root rot is harmful fungi in the soil that thrive once exposed to wet soil conditions.

Two main types of soil fungi can lead to root rot—fusarium and pythium. Fusarium is a common soil fungus that thrives on dead or dying plant tissues, and pythium is a bacterial organism commonly transmitted by fungus gnats (which also thrive in consistently moist soil conditions).

While there are multiple potential sources of root rot, the treatment is the same regardless of the root cause.

Signs of Root Rot

Root rot is easiest to identify by the color of the roots. Healthy roots appear firm, whitish, or cream-colored. Unhealthy roots appear dark brown, black, mushy, fall apart, or smell like decay. Other symptoms of root rot:

• A large number of yellowing or smaller, pale-colored leaves
• A lot of leaves wilting or falling off the plant (unseasonably)
• Brown splotches on leaves
• Stunted growth
• The rapid decline of the plant
  

How Plants Get Root Rot

Overwatering can happen for several reasons. The most common reasons are improper drainage and watering too frequently. Indoor plants are more susceptible to root rot than outdoor plants since water is more easily contained in the soil.

How to Treat Root Rot 

Once established, root rot is hard to treat. The best you can do is remove the parts of the plant that are dying (including the roots) and provide it with fresh soil. If the root rot is widespread and has affected most of the plant's roots and foliage, the plant may be beyond saving. However, if the plant has any healthy roots left, it may be possible to rehabilitate it using the following steps.

1. Remove the Plant’s Soil and Inspect Its Roots.

   Gently remove your plant from its pot and remove as much of the soil from the roots as possible. Inspect the roots and foliage of the plant and identify the rotting portions. Healthy roots are green or white, and firm and rotting roots are brown, squishy, or stringy.

2. Cut Away the Rotting Roots and Foliage

   Using a pair of sharp pruning shears or scissors, gently remove the rotting portions of your plant's roots and foliage. Be careful not to damage any of the healthy growth.

3. Repot With Fresh Soil

   Once you have removed all of the dead or dying roots and foliage from your plant, it is time to repot the plant in fresh soil. Choose a pot with a drainage hole, and ensure the new soil is appropriate for your plant.

Root Rot Prevention

The best treatment for root rot is prevention. Here are a few ways to prevent an overwatering situation that can lead to root rot.

Know Your Plant's Watering Needs

Familiarize yourself with your plant's specific watering and care needs. Some plants require significantly more water than others. An appropriate amount of water for one plant may result in overwatering and root rot for another. 

Choose the Right Soil

Different types of soil or soil mixtures have different degrees of drainage. For example, clay soil retains water well and has poor drainage, while sandy soil is considered very well-draining. The type of soil that you should use varies depending on the plant, so don't just assume that sandy soil will work for every plant. Do some research into which soil is best for your specific plant. 

Provide Sufficient Drainage

Potted plants should also have appropriate drainage to prevent water from accumulating around the roots. The amount of drainage available to a plant is determined by the soil type and container. Houseplants should always be planted in a container with a drainage hole, which allows excess water to drain from the soil during watering.

Many decorative planters do not have drainage holes, so place your plant in a smaller plastic nursery pot and place it inside the decorative planter. When watering, remove the plastic pot, water the plant (allowing excess water to drain from the pot), and then put the plant back inside its decorative planter until the next watering.

Ensure Proper Light Levels

Does your plant get enough sunlight? If a plant does not get enough light, the soil can remain soggy and overly wet, which contributes to root rot. Make sure to plant in a location that gets the right amount of sunlight for your plant, and take into account seasonality and how light may change throughout the year.

Repot Your Plant

If your plant is potted in a container, regular repotting can help keep the soil fresh and prevent diseases, such as root rot. Fresh soil can help improve plant health, so even if you don't repot, you can still change out the soil if you notice it starting to compact.