How To Prevent, Identify & Treat Root Rot In Houseplants

Tips For Identifying & Treating Root Rot In Houseplants

One of the most common issues with houseplants isn’t related to disease. Instead, it is due to cultural and environmental factors like overwatering, which results in root rot disease. The leaves of an over-watered plant typically start to get dull and turn yellow, eventually affecting the entire plant. Overwatering is an easy mistake, especially during the winter months when root rot symptoms are likely to crop up.

So is there a root rot treatment? Will treating root rot save an infected plant? Keep reading to learn all about root rot disease and how to fix root rot in houseplants.

What is Root Rot?

Root rot is an infectious disease caused by fungal or fungus-like pathogens including Fusarium, Phytophthora, Pythium and Rhizoctonia which thrive in wet soil and potting mix. 

How Do Plants Get Root Rot?

Root rot can have two sources. One is prolonged exposure to overwatered conditions that can cause some of the roots to die back due to a lack of oxygen. As they die, they begin to decay or rot away. The rot can then spread to healthier roots and kill them as well, even if the soil conditions are corrected. 

The other source can be a fungus in the soil. The fungus may lie dormant in the soil indefinitely and then suddenly flourish when the plant is overwatered once or twice. The root rot fungus attacks the roots and causes them to die and rot away.

Houseplants get root rot when their root systems are left in sodden, saturated soil, whether it’s due to overwatering or soil that isn’t well-draining. The fungi can attack cuttings, seedlings, seeds, and root systems. Infection often occurs in plants that are already stressed. The stressed plant’s root system then begins to collapse. If root rot isn’t treated, the plant can die. 

What Does Root Rot Look Like? Common Signs of Root Rot

If a plant is slowly wilting and the leaves are turning yellow and dropping from the plant, you will want to check the roots. Wilting is the first sign of stressed or weakened houseplants. It’s easy to confuse this condition with a lack of water, as the symptoms often appear similar. 

Root rot affects the lower leaves of the plant initially, with wilting continuing upward as the disease progresses. To verify the presence of root rot vs. lack of water, you need to examine the roots. Infected roots will be dark, mushy, and reddish or brown in color. Conversely, healthy roots will have lots of feeder roots and will be firm and white. A visual inspection of the root system will identify if root rot is present however, only a lab test can tell which pathogen is present. 

How To Prevent Root Rot

There are a couple of things you can do to prevent root rot. Of course, the number one step toward prevention is not to overwater, but making sure the plant has proper drainage, choosing the correct potting medium, and knowing your houseplants’ requirements will help you to prevent this condition.

Choose the Right Potting Mix

Preventing root rot requires using the correct potting medium. Potting soil should be pasteurized if possible, arable, and well-draining and should contain perlite. Never reuse previously used potting mixes, and don’t use garden soil.

Provide Good Drainage

Always use a plant container that has sufficient drainage holes. Add peat moss to heavy potting soils to increase draining. Do not allow plants to sit in drainage water. 

Know Your Plant’s Needs

While some houseplants have similar requirements, not all of them do. Research your plants and know what their particular needs are. Some plants need water every week or more often while others only need water every two weeks. 

Many plants go dormant when there is less light and sun in the winter. During this period of dormancy, many plants should be watered less. 

Don’t Overwater

Root rot fungi grow and reproduce in wet soil so it’s important to avoid overwatering. Make sure to provide soil that drains well. And don’t forget that drainage holes in pot are crucial for most houseplants. 

Most plants won’t need water until the top 2 inches (5 cm) of soil is dry, but again, know your plant’s needs. Also, the amount of water needed is not only dictated by the type of plant but also by the size and material of the pot, the type of growing medium and environmental factors such as temperature, light and humidity. If you have difficulty gauging how much water to give a plant, use a soil moisture meter. 

Be Careful With Fertilizer

Too much fertilizer can weaken your plant by adding too much salt to the soil. Weakened or stressed plants are more susceptible to diseases.

How To Treat Root Rot

If you determine your plant has root rot, all is not necessarily lost. You can take some steps to treat the disease that may save your plant. Treating root rot as soon as you see the signs will give your plant the best chance to survive.

Prune

Cut away any dead, dying or diseased foliage with sterilized shears. Remove the plant from the soil and gently feel the roots. Roots affected by root rot will look red, brown or black and will feel slimy or mushy. Affected roots may literally fall off the plant when you touch them. Healthy roots may be black or pale, but they will feel firm and pliable. Rinse the root system under clean running water to clean away any soil that may be contaminated. Inspect the roots and using a sharp, clean pair of shears or scissors, cut out any that look diseased. Remember to sterilize your pruning shears again before using them on another plant. 

You may have to remove a significant amount of the root system if the plant is badly affected. If this is the case, clean the shears or scissors with rubbing alcohol and prune back one-third to one-half of the leaves on the plant. This will give the plant a better chance to regrow its roots, as it will not need to support as many leaves.

Repot

Allow the plant’s root system to dry out for 24 hours. Dispose of the soil where the root rot occurred, then wash the pot thoroughly with a bleach solution (or repot the plant in a sterile container). Wash the pot thoroughly with a bleach solution. If possible, dip the remaining healthy roots in a fungicide solution to kill off any possible root rot fungus. Repot the plant using new pasteurized potting soil. 

Water Properly

Again, do not water your houseplant until the top 2 inches (5 cm) of potting soil feel dry to the touch unless you have done your research and know the particular type of plant requires extra irrigation. Use a soil moisture meter. Make sure you are using a well-draining potting soil and a container with adequate drainage holes. 

Water at the base of the plant, never over the leaves which can foster other types of fungal diseases. 

Final Words Regarding Root Rot

Only buy your plants from reputable sources that, if available, are certified root rot free. 

Keep infected plants separate from healthy plants and discard any severely infected plants. 

Sterilize tools and pots between uses. Always use sterile potting soil. 

While it's regrowing roots, do not fertilize the plant, as this may stress it.

Learn more about houseplant care in our Complete Guide To Houseplants