Why Are the Roots of My Potted House Plants Turning Black? [How to treat]

Due to the global accessibility to the internet and social media plants, any trend that begins at some place spreads like wildfire.

One trend that seems to be gaining popularity every year is investing in and caring for potted house plants.

Millennials, being the most active on various social media platforms, like to be referred to as house plant parents and will go as far as to call these indoor plants the new pets of the modern era.

Interestingly, they are not all that wrong. While a potted house plant does not move or bark like a pet dog, its appearance and the way they grow to depend on how one treats them, how and when they are watered, and what environment they grow in.

Unlike outdoor plants that are significantly more resilient, potted house plants are far more vulnerable to unfavorable conditions, and hence, the chances of them dying prematurely due to poor care are very high.

One common complaint most plant parents repeatedly have is that their potted house plant has black roots right before it dies.

However, few understand what black plant root means and what causes its color to change.

Continue reading to learn about why the healthy roots of a potted house plant are so important, what happens when the roots get damaged, what causes their color to turn black, and how you can treat such a potted house plant.

Let’s get started!

Why Are the Roots of a Potted House Plant So Important?

People who have only recently developed an interest in caring for potted house plants usually analyze and deduce how well their plant is doing by the state of its leaves, stem, and flower.

However, these people do not know that the leaves and stems usually show signs of sickness and distress once the problem has already begun.

The roots of a plant are usually the first to get affected by an extreme change in external surroundings.

Since the roots are well hidden in the soil of a potted house plant, it is hard to know when they are being affected by an external change.

Usually, the signs and symptoms of a dying house plant are noticed only after the roots are completely damaged and can no longer be revived.

Hence, it is safe to say that the roots of a plant are one of its most vital organs to stay healthy and alive.

However, what do the roots do that makes them so important?

As we all know, all potted house plants require water and sunlight to carry out photosynthesis to make plant food. This plant food allows the potted indoor plant to have the energy to carry out its functions, fight diseases, and remain upright.

However, if the plant cannot get its required amount of water, photosynthesis slows down, and no more plant food is produced. As a result, the plant loses its energy to stay upright and eventually dies.

This is exactly what makes the roots so vital, as, without healthy and functional roots, the potted house plant will not be able to fulfill its water requirements and will thus die.

How Do the Roots of a Plant Absorb Water?

Water cannot simply move up the stem of a potted house plant against the pull of gravity. Instead, it is sucked up in a similar way to how you would drink water through a straw. This is how it happens:

  • The tiny holes present on the surface of a potted house plant allow some water molecules to transpire out of the plant and evaporate into the atmosphere.
  • As the water molecules leave the leaf’s cells, a vacuum is formed. This vacuum creates a suction force across the plant’s body.
  • As a result, the water in the house plant’s soil is absorbed by the root’s cells, slowly moving up the plant’s body against gravity.
    • Moreover, even if there is insufficient water in the plant’s soil, the roots can grow and move toward whatever amount of water is available to ensure the plant does not get dehydrated.

What Happens When the Roots of a Potted House Plant Are Damaged?

No green plants that need to photosynthesize to create their food can survive too long without water.

Although some hardy indoor house plants need to be watered every other week, they can still die of dehydration if no water is provided to them for extended periods.

Since water can only move into a potted house plant through its root cells, the health and wellness of the roots are essential for the plant’s life.

If the roots are damaged and turn black, the following will happen to the potted house plant:

  • Since no water will be sucked up through the dead roots, the potted house plant will no longer have the water molecules to photosynthesize and create the energy it requires to survive.
    • As a result, all the activities and vital functions going inside the plant will slow down and eventually stop.
    • If this is continued for an extended period, the plant’s leaves will start to turn brown and fall off, its stem will no longer have the strength to remain upright, and hence, the plant will die prematurely.
  • Water moves up a plant through thin tube-like structures called xylem. When no water is pulled upwards despite the growing suction force, the xylem tubes will crush inward, causing the plant’s stem to collapse.
  • When the external weather is too hot, the plant attempts to bring its body temperature down by transpiring water molecules from its leaves.
    • As the transpired-out water evaporates off the leaf’s surface, the cooling effect allows the potted house plant to cool down.
    • However, if no water is transpired out, the plant will not be able to regulate its body’s temperature. As a result, it will die due to overheating.

Hence, the roots of a plant must remain healthy if you want to see your potted planter grow and thrive. Continue reading to learn what causes the roots of a house plant to turn black in the first place.

What Causes the Roots of a Potted House Plant to Turn Black?

Most potted house plant species are generally more sensitive than outdoor plants. This makes it extremely challenging to save a potted house plant once all of its roots have turned black.

Hence, it is important to understand what causes the plant’s roots to darken. Some reasons that may contribute to the potted house plant’s roots turning black are as follows:


People devastated by the loss of a potted house plant due to underwatering usually begin to overwater their house plants to prevent another premature plant death.

However, this is where they go wrong. While some indoor plant species do need regular watering, most need to be watered less frequently to survive.

If such a potted house plant that thrives on lesser water is overwatered, excess water accumulates inside the pot.

This is because the plant cells have a limit to how much water they can absorb. Once they have reached this limit, they will not permit more water molecules to pass through the cell walls.

If the accumulated water is not removed from the pot, fungus can begin to grow inside the soil. This is because fungal spores thrive in moist soils where they can feast on plant matter.

Eventually, the fungus can grow all the way to the plant’s roots, causing them to rot and turn black.

Poor Ventilation

Even if there is only a little moisture in the air, poor ventilation will cause it to dampen a potted house plant’s soil.

Moreover, this becomes an even greater problem when you live close to the sea or in a region where it rains frequently and the air remains humid.

If the moisture in the soil is enough to support fungal growth, the roots will begin to rot and turn black.  

Gloomy and Dark Conditions

Although indoor plants are meant to stay inside a home, most potted house plant species need sunlight exposure.

If such plant species are kept in gloomy and dark conditions and are deprived of any sun, not only will photosynthesis get affected, but the excess water in the plant’s soil will also not get the chance to evaporate.

As a result, the plant’s soil will remain wet for prolonged periods, and the growing fungus will harm the plant’s roots.

How to Treat a Potted House Plant with Black Roots

Treating a potted house plant’s darkened roots is a highly time-sensitive matter. Usually, you can only treat them and save the plant if some part of the root is still alive and healthy.

However, regardless of how the roots are doing, you can still try to save them. Some tips for treating the blackened roots of a potted house plant are as follows:

1. Gently Remove the Potted House Plant from the Soil

Usually, it is hard to know when the roots of your potted house plant have started to rot and change color.

However, you can still try to inspect the root’s health by probing through the pot’s soil. Use a stick and move the dirt around to look for any signs of fungal growth.

If you find fungus growing only on the top layer of the soil, adding fungicides and drying the soil will be enough to kill the fungus.

However, if you notice that the fungus has grown to the plant’s roots, a simple fungicide will not do the trick.

Instead, you will have to gently shovel the infested soil from around the house plant’s roots to completely remove the plant from the soil.

2. Remove the Soil and Fungus from the Roots Under Running Water

Once the potted house plant and its roots are out of the soil, you need to examine the damage.

For this, you need to place the roots under running water at low pressure. Use your fingers or a soft brush to gently remove the soil particles and the fungus from the root’s surface – as much as you can without damaging the roots.

3. Cut off the Root Tips that Are Completely Black and Dead

Once the roots are clean, you will have a better idea of whether the potted house plant can still be saved.

Start cutting off all the root tips and pieces that are entirely black and rotten, and leave only those that still show signs of health.

4. Pat Dry the Roots

Take a soft paper towel and gently pat the roots to dry them completely. If you are worried about your plant dehydrating, you can use a spray bottle to dampen the roots while preparing its pot.

5. Throw Out the Infested Soil and Wash the Pot

The fungal-infested soil the potted house plant has previously grown into is no longer usable and needs to be discarded. Hence, throw it out and wash the pot thoroughly.

Be sure to get into every nook and cranny so that no fungus remains.

6. Replant the Potted House Plant in Fresh Soil

Finally, add some new and fresh soil to the clean pot and replant the roots into the soil. Use the spray bottle again to add just the right amount of moisture to the soil, and voila, just like that, your plant will have a chance at life once again.

Why Are the Roots of My Potted House Plants Turning Black
Why Are the Roots of My Potted House Plants Turning Black

Final Thoughts

Being a dedicated house plant parent is about realizing that your plants are living beings, and you are responsible for ensuring they get the nourishment, care, and timely treatment they need.

Although you cannot directly keep an eye on a potted house plant’s roots as they are submerged in the soil, the state of the plant’s soil, leaves, flower, and stem will indicate how well the roots are doing.

Hence, always inspect your potted house plants closely and begin treatment as soon as you notice dried, darkened, and curled-up leaves. Moreover, always take the time to learn some basic information about your potted house plant’s unique needs and watering requirements so you can ensure the health and wellness of its roots.

You may like the following houseplant articles: