One issue you must look out for in houseplants is root rot. Fortunately, the plant will give signs of root rot, even though the roots are hidden. Common signs include curling or wrinkled leaves, leaf loss, a powdery substance on the soil, and growing mushrooms.
To fix root rot, you should:
- Identify signs of root rot in plants.
- Cut off mushy roots.
- Dip the remaining roots in 1% H2O2 solution.
- Repot the houseplant in fresh soil.
- Water the plant after the soil has dried.
- Find a spot with adequate air circulation.
How quickly you address root rot will determine whether your plant recovers or not. In this article, I’ll discuss the steps to fix root rot. I’ll also highlight the causes of root rot and how a seemingly harmless plant care routines can cause root rot in houseplants.
1. Identify Signs of Root Rot in Plants
Overwatering is the primary cause of root rot in houseplants. When your plant sits in soggy soil for an extended period, fungi and other harmful microbes proliferate in the soil and attack the roots, causing them to become mushy and rot.
In the ground, plant roots grow as they search for soluble oxygen, soil nutrients, and water. However, potted plants cannot grow beyond the confines of the pot. Instead, they rely on well-draining soil to access oxygen through the air pockets.
When you overwater houseplants, the air pockets become compressed, restricting oxygen accessibility. The water also suffocates the roots. They cannot transport nutrients and water to the rest of the plant. Soon, the plants will start showing signs of deprivation.
Some signs to identify root rot include the following:
- Curling or wilting leaves
- Yellowing leaves that eventually turn brown and die
- Falling leaves
- Powdery substances on the soil
- Growing mushrooms
- Unpleasant soil odor
- No new leaf growth
- Constantly wet soil and eventually fungus gnats
- Decaying roots
- Mushy crown
Unfortunately, you can easily mistake some of the signs for underwatering. I once made this mistake and made the situation worse.
Weeks after establishing a regular watering routine, there was barely any change. The curled leaves remained the same, but they also started falling off. That’s when I decided to check its roots, and yes, they were rotting.
Root rot will sometimes present itself differently, depending on the plant and the extent of the rot. In my case, the odor, a common sign of anaerobic bacteria growing in wet soil, was initially missing.
However, over time, the signs became more obvious. Fortunately, I acted before I completely killed the plant with more water.
2. Cut Off Mushy Roots
Once you notice signs of root rot, the next step is to examine the plant roots. This is more or less the confirmatory test because you can easily see the state of the roots. Be keen when checking the roots to ensure you eliminate all the affected sections.
Here are the steps to remove decaying roots:
Water the Day Before Treatment
You should water the soil lightly one day before the treatment. It will help make it easier to remove the plant from the soil.
Gently use a blunt blade or trowel to loosen the soil around the pot. Hold the plant at the crown as you slide it out of the pot.
Remove Soil as You Examine the Roots
You can gently rub the soil between your fingers or run water through the roots to get rid of the soil clinging to them. The dark potting soil can hide the extent of the damage.
Spot Soft, Mushy, or Discolored Roots
Rotting roots change color to brown or black, while healthy roots are whitish and firm. You can pinch the roots lightly to see if they are bouncy. If the root hasn’t changed color but isn’t firm, it may be in the early stages of root rot.
Remove Rotted or Dead Roots
Use sterilized pruning shears to cut rotted or dead roots. You can also use a pair of scissors.
It’s important to get to all the rotting roots, but if more than one-third of the roots are affected, there’s little chance for your plant to recover. If more than 1/3 of the roots are damaged, you may need to divide the plant (depending on the species and structure) or dispose of it entirely.
Cut Off Damaged Leaves and Stems
Pruning the roots warrants the removal of as many aboveground parts to balance the amount of plant matter the roots have to support while recovering.
Rinse Roots With Distileld Water
Finally, rinse the remaining roots with distilled water. Inspect them again thoroughly to ensure that you’ve removed all the rotten sections.
It’s best to leave the roots to dry for a few hours before you treat or repot the plant. This helps reduce root wetness, especially when replanting in damp soil, as required.
3. Dip the Remaining Roots in 1% H2O2 Solution
This step is optional, but hydrogen peroxide (H2O2) is a DIY root rot treatment worth exploring. However, you should avoid it if the plant is severely wilted. This treatment is primarily for the roots.
A badly damaged plant may have severe root rot and incorrect use of hydrogen peroxide may worsen the situation.
Sometimes cutting off rotting roots in houseplants is not enough. The fungi and bacteria may still cause problems if the soil conditions allow their growth.
The EPA and FDA have approved hydrogen peroxide as an antimicrobial agent. However, you should only use it when diluted.
Food-grade hydrogen peroxide products typically have a 35% concentration. At this level, it can be harmful to your plants. You can dilute it by mixing 1 part hydrogen peroxide with 11 parts distilled water, resulting in a 3% concentration.
I recommend further diluting the solution to 1% by mixing 1/2 cup (125 ml) of 3% hydrogen peroxide with 1 cup (250 ml) of distilled water. This amount is often enough for soaking one plant’s roots for 10 minutes.
If you need more liquid, you can increase the volume but keep in mind the following proportion: 1 part 3% H2O2 to 2 parts distilled water.
Hydrogen peroxide in low concentrations poses no risks to the plant. In higher concentrations, it may damage plant roots due to its corrosive properties.
After soaking your plant’s roots, rinse them with distilled water and place them on a clean towel to dry for about 30 minutes before replanting in moist and fresh potting soil.
When used correctly, hydrogen peroxide also has other benefits:
It Can Eliminate Fungi in the Soil
Ideally, you should discard the current potting soil because it may have spores that will, over time, lead to fungal diseases and root rot. But if you want to reuse the old potting soil, you can sterilize it using a higher concentration of hydrogen peroxide.
Multiple studies showed that hydrogen peroxide can kill numerous microbes at varying concentrations and durations of exposure and is, therefore, widely used in medical and laboratory settings.
However, it can lead to the death of beneficial microbes as well.
It Aids With Soil Aeration
When poured into soil rich in organic compounds, hydrogen peroxide quickly decomposes and releases water molecules and oxygen. This oxygen can then be introduced into the soil for your plant’s roots to absorb.
It’s an Excellent Disinfectant
As discussed, medical and laboratory professionals use hydrogen peroxide to disinfect laboratory apparatuses. It also works as a cleaning agent at home. You can also disinfect the old pot with hydrogen peroxide, especially if you intend to use the same pot in the future.
You can also spray or drench the soil with a 1% hydrogen peroxide solution over the next few weeks. However, you should be careful because hydrogen peroxide can sometimes weaken the plant, especially in high concentrations.
You can start by spraying the roots to see the plant’s response before drenching the soil with the solution or watering the plant over an extended period with hydrogen peroxide.
Using Hydrogen Peroxide Safely
When using the hydrogen peroxide treatment, you should take several precautions.
Wear Protective Clothing
Hydrogen peroxide poses little risk to plants, especially in low concentrations. However, it can cause skin and eye irritation if you don’t protect yourself when diluting a concentrated solution.
Avoid High Concentration Solutions
You should avoid using hydrogen peroxide in higher concentrations. 1% hydrogen peroxide is sufficient for houseplants. You may get away with hydrogen peroxide in higher concentrations when you treat fungal infections in outdoor garden soil, especially when drenching soil over a large area.
Only Use It on Plant Roots
Diluted hydrogen peroxide is beneficial when applied to the plant roots, but it can cause leaf damage when the concentration is over 1%. Unless you’re treating leaf problems like white mold, limit your application to the plant roots.
Don’t Use It on Very Damaged Plants
Avoid using hydrogen peroxide in case of extensive plant damage. In most cases, the plant will be unlikely to recover if the rot has spread to more than 30% of the plant.
If you’d like to explore more options than using hydrogen peroxide to disinfect root rot soil, check out my other article: How To Disinfect Root Rot Soil: Easy Guide
4. Repot the Houseplant in Fresh Soil
Since you’ll be removing the damaged roots, avoid transferring the plant into a pot that is too large because it will sit in wet soil, leading to root rot again. Depending on the amount of roots you remove, you may need to repot your plant in a smaller or similar-sized pot.
You can take several measures to ensure the rot doesn’t recur when repotting.
Use a Similar-Sized Pot
You should use a similar-sized pot if you removed less than 1/3 of the roots. However, if you divided the plant to save a small section with healthy roots and shoots, go for a smaller pot. Ensure that the new pot is only up to 2 inches (5 cm) wider than the diameter of the rootball.
Choose a Pot With Drainage Holes
Ensure the new pot has drainage holes as well. One reason plants suffer from root rot is when the pot lacks adequate drainage holes.
Get a Fresh, Sterile Soil Mix
Since the soil mix is sterile, the potting mix shouldn’t have fungi spores, which can eventually grow and cause root rot.
Select a Porous Pot
Use a breathable pot, such as unglazed terracotta. The new pot should be porous for better aeration and faster release of excess moisture.
Add Extra Pumice
Adding pumice will improve air circulation in the soil and boost the absorption of water, dissolved oxygen, and nutrients.
Avoid Adding Fertilizer When Repotting
You should instead wait a few weeks for the plant to recover before adding plant food. Alternatively, you can add organic matter that acts as a slow-release fertilizer, such as worm castings or compost. Both materials also help with drainage.
5. Water the Plant After the Soil Has Dried
Plants treated from root rot should be repotted in moist soil (watered a day before the transplant). It’s important to avoid watering the plant immediately after repotting. For cacti and succulents, you’ll need to wait 10-14 days before watering them.
On the other hand, you can deeply water moisture-loving plants when the top 1-2 inches (2.5-5 cm) of the new potting mix is dry. Allow the excess moisture to drain from the drainage holes before placing your pot back on its saucer.
You are probably hesitant about watering your plant, but your plant is safe now that you have treated root rot. Plus, the houseplant still needs water to recover. Remember, the root rot hindered water absorption, so the plant was thirsty.
After the first deep watering, avoid watering again until the soil surface is sufficiently dry, depending on your plant’s moisture requirement.
The plant care routine may change slightly after treating root rot. You may have to give the plant more time between waterings, but you should keep an eye on your plant for signs of thirst, such as shriveled or dry leaves.
If the soil dries out faster, water more frequently. If it takes longer to dry, you must wait a little more before watering. Factors such as humidity levels, weather conditions, and the plant’s location will determine how fast the soil dries out.
6. Find a Spot With Adequate Air Circulation
Poor air circulation is another cause of water retention in plants. Check the current spot for your houseplant, and see if it receives adequate air circulation.
Some areas you should avoid placing your houseplant include:
- An area with too many indoor plants, especially those with large foliage
- A spot too close to the walls
- Crowded areas, including places with too many books and photo frames (if you must use these spots, ensure the plant is on higher ground where the soil has adequate air circulation)
- Damp spots
Find an area with bright, indirect light and adequate air circulation for your houseplant. However, you must also keep your plant’s humidity requirements in minds. You can use a humidifier if the level is too low, especially for tropical plants.
If you have few options on where to place the plant, you can take the following measures to improve air circulation:
Find a Spot Close to a Window
If the outdoor temperatures are moderately warm and stable, open the window to allow fresh air. You can also move the plants close to the window for a little while to prevent damp build-up, especially if they don’t get sufficient air circulation.
Circulate Air With a Fan
You can also use a fan to circulate the air. Use a floor or oscillating fan to circulate air specifically around the indoor plants.
Rearrange the Plants
Rearrange the potted plants that are close together so that there is sufficient space between them, allowing for more air circulation.
Can a Houseplant Recover From Root Rot?
When you first notice a change in your plants, the period between correct diagnosis and treatment matters. Root rot can spread quickly, especially if your plant is in poor health to begin with. How well the plant recovers will depend on the extent of the root rot.
A houseplant can recover from root rot if it has healthy roots and if you cut off all the rot. Pythium, Phytophthora, and Fusarium fungi thrive in the soil and dying plant tissues, making plant recovery difficult. Fresh potting soil, the right pot size, and adequate air circulation will aid plant recovery.
You cannot reverse severe root rot. A plant that loses most of its roots will struggle to survive. Instead of discarding it, you can divide the roots or propagate the cuttings.
Signs a Plant Is Recovering
After treating root rot, houseplants don’t take long to bounce back. Some plants start showing signs of recovery within 1-2 weeks. However, if the damage to the roots is extensive, the recovery may take several weeks because the plant will need more root growth to heal.
Here are some of the signs your plant is recovering from root rot.
New Leaf Growth
When your plant gets new leaves, you can be confident that the root rot treatment worked. This is an obvious sign that the roots are healthy enough to nourish the entire plant.
More Green Leaves
Yellow leaves are a sign of stress in plants. When the plant is not nourished enough, some leaves turn yellow. As the plant recovers, the new foliage will be greener and healthier.
The Leaves Stop Falling Off
Since you can’t keep digging out the houseplant to see if the root rot is gone, you should observe the leaves. When they stop falling off, it is a sign that the plant is in recovery.
Most plants recover after root rot if you remove all the damaged tissues. If you accidentally leave some rot, it will spread, and your plant may never recover. So, you must be very keen when cutting off the affected roots.
Your houseplant care, such as watering when the plant needs more water and improving air circulation, will also determine how soon you will start seeing the plant bounce back after treating root rot.
How to Prevent Rotting Roots In Houseplants
Root rot can creep on anyone, including people touted to have a green thumb. The roots are hidden, and it takes some time before you notice signs of plant distress. Usually, by the time the plant “calls for help”, the damage to the roots is already extensive.
You’ll need to act fast to save your houseplant.
Fortunately, root rot is avoidable, and you can take steps to ensure your plant is not affected by it:
Check if It Needs More Water
You should use a moisture meter to check if the plant needs more water.
The finger test will help you decide if you should water the plant. However, it doesn’t consider the probability of wet soil at the bottom of the pot.
A moisture meter has a long probe that goes several inches (5+ cm) into the soil, giving a clearer picture of the moisture level. Regular readings will also guide you on the best watering schedule based on the changes in soil moisture levels.
Provide Adequate Light
Ensure you follow lighting requirements for your plants. Low light conditions limit water evaporation. So, a plant that requires low light should not be watered as often as one exposed to bright light.
Supplemental grow lights will aid plant growth, resulting in healthy root systems.
Only Use Pots With Drainage Holes
Drainage holes give you a little leeway should you overwater your plants. At least, the excess water will drain out, and your plant will only utilize the water it needs. However, you must be cautious because drainage holes are only helpful if you follow the right watering routine.
Get the Right Pot Size
Planters that are too big for the plant retain wet soil for longer, leading to root rot. The ideal pot should be at least an inch (2.5 cm) wider than the roots of slow-growing plants. Plants that grow quickly need a pot that is at least 2 inches (5 cm) wider.
Go for Unglazed Planters
Unglazed planters will help to suck moisture out of the soil, reducing the risk of root rot.
Use Well-Aerated Soil Substrate
If you have doubts about the soil mix, add pumice or perlite to improve aeration. Alternatively, you can choose specialty soil mixes for specific houseplants, such as succulent and cacti potting mixes.
Water Houseplants Correctly
Overwatering can take the form of using little water too frequently or using too much water after the soil gets too dry. Both cases can lead to the plant roots sitting in wet soil, resulting in root rot.
Understand your plant’s moisture requirement and the quality of your potting mix to establish a good watering practice.
Here is a video offering tips on preventing root rot in houseplants.
Root rot is a challenge that anyone with houseplants encounters at some point. You should analyze the causes and point to the mistakes that may have led to this. However, the priority is getting to the roots and checking if some can be saved.
Once you fix the root rot, figure out the cause and how to keep it from happening again.
To prevent root rot, you need to observe the right plant care routine and understand the impact of the environment on the plant and its vulnerability to root rot.