Mold in Pothos Soil: 4 Types & How to Control Them

Pothos (Epipremnum aureum) is an elegant tropical vine that has become popular in any indoor space – homes, offices, lobbies, and restaurants. It has the reputation of being a resilient, easy-care plant that is tolerant of indoor conditions.

But sometimes, when there is too much water and humidity, or not enough light and air circulation, your plant and its soil can develop problems, and one of those is mold.

The Short Answer: Mold in Pothos Soil

Effectively manage mold in pothos soil with these steps: Carefully remove visible mold, position your plant in a well-ventilated area, and adjust watering routines to let soil dry between waterings. Use a well-draining soil mix to reduce moisture retention, apply cinnamon as a natural fungicide, or replace the soil entirely in severe cases. Regularly monitor your pothos for progress and healthier growth.

What Is Mold?

Molds are everywhere. They are a type of fungus, and their spores are spread by air currents or splashing water outside in the garden and inside on your plants and in the potting soil. They can remain dormant for years, but they will start to grow under the right conditions and can attack your plant.

Molds on your houseplants and in their soil can also trigger allergies and problems for people with asthma, so it’s crucial to prevent them from growing and treat them if they arise.

There are many species of molds, but here are four of the most common types of mold that you might see on your Pothos.

Types of Mold in Pothos Soil & How to Control Them

White mold

White mold is a fuzzy growth on the surface of the soil that is a harmless saprophytic fungus. It feeds on decaying organic matter, such as dead leaves and other organic material in the soil, but it can compete with your Pothos for nutrients and should be removed.

How to Control White Mold

You can start by gently scraping off the top layer of soil, removing all of the mold. Next, add fresh soil, then sprinkle the surface with cinnamon (yes, cinnamon!), which contains cinnamaldehyde, a natural fungicide, to prevent reinfection.

Alternatively, you can water the fresh soil with 1 part 3% hydrogen peroxide to 3 parts water. It oxygenates the soil, which the plants love, and will kill any remaining mold.

A commercial fungicide with copper as an ingredient is also a good choice, as is a solution of potassium bicarbonate and water, a natural fungicide.

If you have a thick growth of mold, discard the potting mix, wash the pot and the plant thoroughly and treat them with fungicide before repotting with fresh soil.

Sooty Mold

Sooty mold is a dark gray to black growth that appears on the honeydew secretions of insect pests such as aphids, whiteflies, soft scale, and mealybugs on the leaves. If the growth is too thick, it can inhibit photosynthesis by blocking light from the leaves and stunting the plant.

How to Control Sooty Mold

In this case, if you can control the pests, you can eliminate the mold. First, gently run water over your plant to knock off as many pests as possible. Then spray with horticultural soap and/or Neem oil to kill the remaining ones. Once your Pothos is free of pests, wipe down the leaves with soap and water to get rid of the mold.

Gray mold (Botrytis blight)

Gray mold, AKA Botrytis blight, is a grayish-tan fuzzy growth covering the leaves and stems. Like most other molds, its spores are airborne and can be spread by air currents or splashing water. 

This mold moves quickly through a plant and causes the collapse of its tissues, shriveling leaves and stems, and eventual death of the plant.

How to Control Gray Mold

Cut out the dead parts of the plant, making sure to wash your hands and scissors or shears so that you don’t spread any spores to other surfaces or plants. Then, put your Pothos in quarantine away from your other plants with low humidity.

If it’s warm outside, you can take your Pothos out and put it in a bright location out of the direct sun, like a porch or patio with plenty of air circulation around the plant. Then, spray it with a fungicide or Neem oil and allow the soil to dry out before bringing it back inside.

Root rot (Phytophthora, Pythium)

healthy pothos roots
Healthy pothos roots

The dreaded root rot of houseplants is generally one of two molds, Phytophthora or Pythium. They live in the soil and will attack and rot the roots of plants and can cause droopy, yellow foliage, and death of the plant.

How to Control Root Rot

Since root rot symptoms are only visible above the soil, you’ll need to look at the roots to identify the mold and control it.

Tip the pot on its side and gently remove the root ball. Shake off the soil so that you can get a good look at the roots. If they are black, mushy, and smell bad, your pothos has a case of root rot.

Cut away the infected roots with clean scissors or shears and dispose of them away from your other plants. Then, treat the remaining roots with Neem oil or a commercial fungicide and plant them in fresh soil in a clean pot. Be sure to discard the old, infected soil – never reuse it.

What Causes Mold to Grow?

Several factors can work together to create a perfect environment for mold to grow:

  • Overwatering your plant
  • High humidity coupled with poor air circulation around the plant
  • Poor drainage causing a buildup of water in the soil
  • Warm temperatures
  • Low light
  • A buildup of dead leaves on the soil’s surface

How to Prevent Mold from Growing

Overly moist soil and stagnant air around the plant create a breeding ground for mold, along with the other conditions mentioned above.

So, to keep your Pothos healthy and mold-free, you’ll need to give it the conditions it needs: the right amount of water, suitable soil and drainage, humidity with adequate air circulation, the right temperature, enough light, and the soil’s surface free of debris.

Watering correctly

pothos plant with water and sunlight to help it grow faster.

Watering correctly is perhaps the most important thing you can do to keep your Pothos from developing mold. The mantra of houseplant care is “Don’t overwater!”

It would be best if you allowed the soil some time to dry out and the Pothos some time to absorb the water already in the soil. When you do this, the amount of water will stay balanced with the other growth conditions, and your plant will remain healthy and mold-free.

The best time to water pothos is in the morning when the soil will have all day to be absorbed and dry out to minimize the chance for mold growth. You will need to water more frequently in the spring and summer when your Pothos is actively growing than in the winter when its growth slows.

When the soil is dry, 1” to 2” down from the top, it’s time to water. Water thoroughly so that it runs through the soil and out the drainage holes in the pot. Let it drain, then empty any remaining water in the dish or tray underneath the pot.

It’s best not to have a watering schedule. Instead, monitor the soil moisture and water again only when the soil is partially dry. A moisture meter can help you determine when it’s time to water.

Humidity

This is a tricky one. Pothos plants love humidity, but too much humidity with stagnant air around the plant will invite mold growth. Households average about 30-40 percent humidity, especially in the winter when the heat is on, but it’s healthiest for your Pothos to have humidity levels at about 50-60 percent.

This can be achieved with a pebble tray, water, or humidifier. Just be sure there is enough air circulation around the plant to discourage dampness and mold problems while boosting the humidity levels. An oscillating fan set away from the plant can help.

Soil, Drainage, and Your Pot

girl repotting a pothos plant into a pot with no drainage holes

Growing Pothos in the right kind of pot and houseplant soil is also essential to its care. Your potting soil provides the structure for your Pothos to sit in and absorb oxygen, water, and nutrients. Above all else, it must be loose and well-draining to physically maintain air spaces for the roots to stay healthy and disease-free.

You can use a good commercial potting mix that you amend with perlite, coco coir, orchid bark, sand, or peat moss. This will allow water to drain through the soil and let the roots “breathe.” Molds will not grow when there is plenty of air within the soil.

Unfortunately, all potting soil will have mold spores and often have fungus gnats eggs. Unless you see mold contamination in the bagged soil, it should be all right unless it becomes too wet.

To prevent any future problems arising from the soil, you can spread it out on a tarp to dry in the sun. An alternative is treating the soil with 1 part 3% hydrogen peroxide to 3 parts water, killing mold spores and fungus gnat eggs.

The pot you use can affect your plant’s growth, too. Terracotta pots breathe and dry out quicker than plastic, ceramic, or composite pots, but whatever kind you choose, ensure that it has at least one drainage hole at the bottom

This is essential to keep the roots and soil from developing molds.

Temperature

Pothos are tropical plants that do well in warm temperatures of 65 to 75 or 80 degrees, which are also hospitable for mold growth.

But before you adjust your thermostat downward for your Pothos, remember that potting soil dries out quicker in the warmth, which is healthier for the plant. And if you keep the other growth conditions in balance, the temperature should not be a problem.

Be careful at both ends of the thermometer. In the summer, especially outdoors, keep your Pothos in the bright shade or a cool area when temperatures soar to 90 degrees and above. And in the fall, bring your plant in when temperatures are predicted to dip below 50 degrees.

Light

pothos with light shining on a wood table.

They are understory plants in tropical rainforests that run along the ground and climb trees. Pothos never see direct sunlight in their native habitat, so they do best with similar bright, indirect light as houseplants.

This is important because harsh, direct sunlight will burn their leaves, but low light will slow down the plant’s growth and keep it from absorbing water at a healthy rate, inviting mold to grow.

An east- or south-facing window is perfect if the plant isn’t in the direct sun. If your Pothos is outdoors for the summer, ensure it’s in a shaded area that still gets bright light.

Keep Your Soil’s Surface Clean

A buildup of dead leaves and organic debris on the soil’s surface can invite molds to grow, so it’s good to regularly clean off the top of the soil to prevent this from happening. Also, you will see more organic buildup if your Pothos is outside in the summer when breezes can deposit foreign materials in your pot.

When conditions are in balance, especially water, and humidity, with enough air circulation and light, you should be able to maintain a healthy and mold-free Pothos for years to come.

Author & Editor | + posts

Nancy has been a plant person from an early age. That interest blossomed into a bachelor’s in biology from Elmira College and a master’s degree in horticulture and communications from the University of Kentucky. Nancy worked in plant taxonomy at the University of Florida and the L. H. Bailey Hortorium at Cornell University, and wrote and edited gardening books at Rodale Press in Emmaus, PA. Her interests are plant identification, gardening, hiking, and reading.