Calathea Root Rot (Signs, Causes, and Treatment)

Last Updated on June 10, 2022 by Admin

Calathea root rot is a frustrating problem because it can destroy an otherwise very beautiful plant.

What’s worse is that calathea are best propagated via division which makes it hard to save the plant in case the situation becomes dire.

Unfortunately, if you do wake up one day and suspect there’s even a possibility of root rot attacking your calathea, immediately check the root system.

Don’t take chances.

Calathea root rot is a result of overwatering. This results in yellow leaves and wilting. The soil will also be wet and mucky.

If you notice these signs, unpot the plant and check its roots. Any brown or dark roots that smell bad and look mushy mean there is root rot.

This requires pruning the damaged roots and treating the remaining healthy roots with fungicide.

Once that’s done, repot the plant in fresh, dry soil.

Table of Contents

Calathea Root Rot Symptoms

Knowing calathea root rot symptoms is crucial in order to save your plant. Before you begin any kind of treatment, the first step will always need to be diagnosing the problem.

And you will rely on the plant’s symptoms to be able to identify the issue.

Below, I’ll break down the signs of calathea root rot into the early symptoms, advance symptoms and when to know the chances of saving the plant is unlikely.

Early Signs of Calathea Root Rot

If in case there is root rot, this is the best time to catch it. Finding out the problem here likely means that only a smaller part or minor section of the root system has root rot.

This gives you a very good chance of saving your calathea.

Stunted Growth

Slow growth that will later stunt is a common symptom.

This happens as the plant will struggle due to the reduced amount of water and nutrients that are absorbed by the roots.

As such, if you notice the plant is not producing new leaves at the rate it normally does or the other leaves are not developing as they should, it usually means something is happening.

Yellow Leaves

Yellow leaves are another common sign of overwatering.

However, just because your calathea is developing yellow leaves does not mean it has root rot. That’s because yellow leaves can be a sign of other problems as well.

But if you suspect that there is overwatering which is what is causing the yellowing, check he soil.

Wet, soggy soil is a dead giveaway that the plant is being overwatered.

If this is the case, I like to play it safe and check the roots to see if there is root rot or not. Better to be safe than sorry, right?

Drooping Leaves and Stems

Again, wilting and drooping can be caused by a number of things.

So, it is not a definitive symptom that will allow you to say that there is calathea root rot. Instead, you want to check for other potential symptoms like yellow leaves and wet soil.

That said, when the plant has root rot, your calathea will droop and wilt.

Advanced Signs of Calathea Root Rot

The advanced signs of calathea root rot are more dangerous.

Unlike the early stages where the signs are more general and can mean other problems, the advanced signs of calathea root rot are definitive.

Once you see them, you can confirm there is root rot.

However, it also means that the damage is further down the road. Thus more serious.

At this point, once you confirm calathea root rot, it is important to take immediate action in hopes to try to save the plant.

Black or Brown Spots on Leaves

Black and brown spots signify damage to the laves due to lack of water, oxygen and nutrients.

This is caused by the reduces absorption of these by fewer healthy roots.

The longer the root rot persists, the more spots you’ll see on leaves.

Brown Leaves

Brown leaves are a later symptom of calathea root rot.

By this time, you already have yellow leaves due to overwatering. And next comes the browning of the leaves.

This happens because rotten roots don’t function anymore.

So, the more roots that have rotted, the less water and nutrients the plant is able to absorb from the soil.

The lack of moisture means that water does not reach the leaves causing them to turn brown.

As such, you’ll see a combination of yellow and brown leaves on your calathea.

Foul Smell Coming from the Roots

A foul odor or stench will be noticeable when you take a whiff of near the surface of the soil.

That stink is coming from the roots that have rotted.

And once you unpot the plant and get closer to the root system, the smell will become even more obvious.

Brown or Black, Mushy Roots

This is the ultimate confirmation.

Healthy roots are white in color. They are firm to the touch but very flexible and pliable.

On the other hand, rotten roots are soft, mushy and easily break. They are brown or black in color and have a bad smell to them.

If you see any rotten roots, even if it is just a few, tit immediately confirm the presence of calathea root rot.

Always remember that root rot spreads quickly. So, you need to take immediate action.

Signs that Calathea Root Rot is Beyond Saving

These are fatal signs. They are very dangerous and tell you that your calathea is in very imminent danger of possibly dying.

At this time, not only is the calathea root rot severe, it is now spreading.

Mushy, Swollen Stem

This is a sign that the root rot is now making its way up to the stem.

The stem of your calathea is usually strong and firm allowing it to hold up large leaves. Now, they’ve become soft, mushy and swollen.

Majority or All Roots are Black

Healthy roots are what will allow a calathea with root rot to survive and recover.

However, if all of the roots or almost all of the roots have rotted, no matter what you do, the remaining roots will not be able to support the plant since they won’t be able to absorb enough water or nutrients to keep the plant healthy.

How to Save Calathea from Root Rot

Once you’ve confirmed the calathea root rot, the next step is to begin formulating a plant to save the plant.

Keep in mind that calathea root rot can be fatal.

So, it is very important to treat the plant as early as possible in hopes that the damage has not gotten severe yet.

Stop Watering

In almost all cases, the cause of calathea root rot is overwatering. This is what puts the roots at risk.

Therefore, it is important to cut off the water supply at least temporarily as you try to save the plant.

By this time, your calathea has been in an overwatered state for a while. So, by not adding more water and allowing the soil to dry, you give it some reprieve.

Prune Rotten Roots

The next step is to prune the rotten roots. Root rot spreads. And it does so at a fast rate.

Therefore, this is one way to stop the damage and rotting from spreading.

If you leave root rot to run its course, you’ll see it spread and soon take over the entire root system. It will also spread upwards to the stems causing stem rot.

Therefore, trimming off the rotten roots will help stop this spread.

Healthy roots are white in color and flexible. They are firm to the touch as well. On the other hand, rotten roots are dark brown to black, have a foul smell and mushy texture.

Make sure to sterilize your cutting tool before you make any cut.

And avoid cutting off any healthy roots. Your calathea will need each one of these to try to survive and recover from the root rot.

Prune Damaged Leaves and Stems

In addition to pruning the rotten roots, you also want to remove all the damaged leaves and stems.

These including the yellow, brown or blackened leaves. Any leaves with unusual markings like brown and black spots are also to be trimmed off.

And if you see any infected or rotten stems, cut them off as well.

Keep in mind that root rot spreads to other parts. Additionally, the symptoms also affect the plant above the ground.

Since these damaged parts will not recover and become healthy again, it is best to remove them as soon as possible.

This way, your calathea is able to focus all of its energy on maintaining healthy leaves and pushing out new shoots and leaves later on after recovery.

One other thing to note is that if you pruned more than a third of the roots system in the previous step, it is also a good idea to trim off the corresponding amount of leaves on top.

This will reduce the workload of the smaller root system in order to save the plant and support it later on.

Also, make sure to sterilize the blade again before you prune the leaves and stems. The cutting tool was just used on rotten roots. So, you do not want any of the pathogens from there to get passed to the other parts of the plant.

Also, be careful in discarding any of these dead, decaying or infected parts of your calathea.

Treat the Healthy Roots with Fungicide

While overwatering is the main cause of calathea root rot, what makes root rot usually comes down to one of two things, suffocation or fungal disease.

Excess water puts the roots in a precarious situation.

The more water there is that fills the soil, the less air will be available.

So, at a certain point, you’ll see the roots start to suffocate as they’re deprived of oxygen due to too much moisture.

If this persists, the roots will eventually suffocate to death then rot.

On the other hand, if the roots do not suffocate, the wet conditions make the environment conducive for fungal development.

Certain fungi eat through the roots and destroy them.

As a result, root rot sets in as well. And it will continue to spread through the entire root system if you do not intervene.

In case the latter is what caused calathea root rot, it is important to treat the root system with fungicide or hydrogen peroxide.

This will kill any remnants of the pathogens in the remaining healthy roots.

In doing so, it eradicates the fungal infection and prevents any possible future resurfacing after you’ve repotted and saved the plant.

You can use a fungicide solution or a hydrogen peroxide solution and soak the root system in it.

After that, lay the calathea over a several newspapers to allow it to dry.

Disinfect the Pot & Throw the Soil Away

While you wait for your calathea’s roots to dry, the next thing to do is to disinfect the pot as well.

This can harbor some of the fungal pathogens on it.

Therefore, it is a good idea to sterilize the container.

You can use the hydrogen peroxide solution or a light bleach solution to do this. You can either scrub the pot with soap and water then apply the solution. Or you can just soak the entire pot in the solution.

I prefer the latter because it is more convenient and requires less effort.

Leave the pot in the solution for about 5-10 minutes. Then place it outside under the sun to dry.

Additionally, it is also important to carefully discard the soil used for your calathea.

Like the roots and the pot, the soil will have pathogens as well that can cause future root rot. So, you do not want to use it again.

Carefully throw the soil away.

Both the soil and pot are infected. And if you use them on other plants in the future, the fungal root rot will likely resurface.

So, disinfecting the pot is the best way to avoid this. And throwing away the soil lets you avoid future problems.

Repot the Calathea

When the calathea’s roots have dried, it is time to repot the plant.

Here, select a new pot that’s just right for the plant.

Avoid a container that is too large or too small. Instead, pick one that is 2 to 3 inches wider than the entire root system.

This will give the roots enough room to grow. But not too much that you increase the risk of overwatering.

Next, fill the container with well-draining soil up to about a third of the way.

Then place your calathea in the soil before filling in the remainder of the space in the pot with the potting mix.

Don’t Water Temporarily After Repotting

Since your calathea’s root rot was caused by overwatering, don’t water the plant just yet.

Let the soil stay dry for at least a few days to a week or so.

This will let the plant recover faster.

After that, you can start watering the plant again with an adjusted watering routine.

Adjust Its Watering Schedule

To avoid future cases of overwatering, it is very important to modify your watering schedule.

Here, you want to emphasize on two things.

Allowing the soil to dry between waterings
Watering consistently.

Calathea like moist soil. But they cannot stand wet, soggy soil.

Therefore, watering too often is a no-no.

Instead, only water the plant once the top 2 inches of soil has completely dried. You can stick your index finger into the soil up to the second knuckle.

If the soil at that level feels dry, it is time to water.

However, if the soil feels moist or wet, don’t water. Wait a 3-4 days before you check the soil for moisture again.

Provide Proper Care & Living Conditions

In addition to proper watering, other care and living conditions will also help keep the plant healthy.

Giving your calathea these things will allow it to recover from root rot.

Note that root rot recovery is a long road for any plant. And you can expect it to take months before the plant even starts showing signs of new growth.

So, be patient.

In the meantime, it is very important to give it an ideal living environment to keep it on its path to recovery.

Give in bright, indirect light. Also, place the calathea in moderate to warm temperatures. Avoid any cold areas in your home.

High humidity is often best. But as long as you keep humidity at 40% and above, it will be fine.

Of course, avoid overwatering the plant.

Don’t Feed the Plant for a While

During this time, you also want to avoid giving your calathea fertilizer.

It won’t be doing any growing during the next few months. Instead, it will battle to survive and try to recover from root rot.

As such, it won’t need plant food.

Giving it fertilizer will make the plant redirect its energy from saving itself to trying to grow new shoots or leaves.

You won’t get much from the latter.

And the loss of focus will also make recovery harder.

Plus, any overfertilizing will add more stress to an already stressed out calathea.

Propagate Your Calathea If It Cannot Be Saved

Unfortunately, not all calathea with root rot can be saved.

If you unpot your plant and notice that almost all of the roots or all the roots are rotten, then the likelihood of saving the plant is low.

In this case, propagating your calathea is your best bet.

Propagation will allow you to start a new plant or plants that will eventually grow into clones of your mother plant.

Since the odds of saving the mother plant from root rot is low, you want to have a backup plan so that in case you lose the plant, you still have new calathea that will eventually grow into mature ones later on.