Mold is a type of fungus commonly found in warm humid areas. When it grows in houseplant soil, mold can cause the plant to wilt and eventually die. The fungus can also release spores into the air which can be harmful to people with mold allergies or asthma.
Mold in potting soil can appear in various forms, but some common signs include the following:
- Discoloration: The soil may look grey or black, or it may have yellow, or green patches. The mold may also appear as tiny white bugs in the houseplant soil.
- Slimy texture: The mold may appear as a white fuzzy or slimy coating on top of the soil or mixed throughout it.
- Musty odor: Mold produces microbial volatile organic compounds and this may make the soil have a musty or damp smell.
- Root rot: Mold may also damage the roots of the plant resulting in stunted growth, wilting, and even death of the plant. The roots of a cactus plant in particular may appear brown and mushy instead of white and firm.
It’s important to note that mold can sometimes be hard to spot when growing beneath the surface of the soil. A thorough inspection of the soil may be needed to help uncover the problem.
Mold in houseplant soil Causes
There are several factors that can lead to the growth of mold in houseplant soil:
- Over-watering: Constantly waterlogged soil can encourage the growth of mold. Excess water in the soil may also kill the plant due to poor air supply around the roots.
- Poor drainage: If the soil does not drain properly, then the accumulation of water leads to mold growth. A pot without functional drainage holes can also cause mold problems in the soil.
- High humidity: Mold thrives in warm, humid environments. If the area where the plant is located is particularly humid, it can increase the likelihood of mold growth.
- Poor air circulation: Places with poor air circulation tend to remain damp. Placing your plants in such areas may result in the growth of mold in the potting media.
- Contaminated soil: If the soil has been contaminated with mold spores, it can lead to mold growth in your plants as well.
- Unsterilized container: Reusing unsterilized containers when growing or repotting your plant may the source of mold in your houseplants.
How to get rid of mold in plant soil
Mold produces spores or toxins which can be harmful to humans and animals if inhaled or ingested. When getting rid of mold in houseplants, it is important to take safety precautions to protect yourself and others.
Wear gloves to protect your skin from coming into contact with the mold. Additionally, put on a mask to protect your lungs from inhaling mold spores. Work in a well-ventilated area and dispose of any moldy plant material and soil in a sealed plastic bag to prevent the spread of spores.
To get rid of mold in plant soil, follow these steps:
- Carefully remove the affected soil from the plant pot and discard it safely in a plastic bag for disposal.
- Clean the pot thoroughly with warm, soapy water and a scrub brush.
- Allow the pot to dry completely before adding new soil and sterilize by soaking it in a solution of one part bleach to 10 parts water. You may also use a new pot instead.
- Fill the pot with the soil with fresh, sterile soil. Be sure to use the well-draining soil recommended for your plant.
- Repot the plant in your new soil and water as needed.
- Place the plant in a well-ventilated lit area and avoid over-watering.
It’s also important to note that mold can grow in houseplant soil as a result of high humidity or poor airflow in your home. So, you may want to address these issues in order to prevent mold from returning.
Tips for preventing mold in houseplant soil
Preventing mold growth is a better option than controlling it, as it is less expensive, less disruptive, and better for your health. Mold in houseplant soil can be prevented through the following tips:
- Use well-draining soil: Make sure the soil you use for your houseplants has good drainage abilities to prevent water from sitting in the soil for too long after watering the plants.
- Avoid over-watering: Always water your houseplants when the top inch of the soil feels dry to the touch. Over-watering can lead to mold growth, discoloration, stunted growth, and death of the plant.
- Increase air circulation: Place your plants near an open window where they can get plenty of air fresh air. You may also use a fan in damp areas to promote evaporation and reduce humidity.
- Keep humidity in check: Use a humidity gauge to monitor the humidity levels in your home, and reduce it if necessary by using a dehumidifier or air conditioner.
- Monitor soil moisture: It is also important to check the moisture level of the soil before watering your plants. You may use a moisture meter or by inserting a finger in the soil to check.
- Clean up debris regularly: Dead leaves, fallen flowers, and other debris can hold moisture and create a suitable medium for mold growth. Therefore, clean up the debris regularly to keep the area around your houseplants dry.
While mold naturally plays an important role in breaking down organic matter, it can also cause problems if it grows indoors. To prevent mold growth in houseplant soil, it’s important to ensure proper drainage, avoid over-watering, and keep the area where the plant is located well-ventilated.
If you suspect mold in your plant’s soil, it’s important to replace it with fresh, sterile soil and sterilize the pot before reusing it. Be sure to dispose of the moldy soil in a sealed plastic bag to prevent the spread of spores.
- “A Brief Guide to Mold, Moisture, and Your Home” by the US Environmental Protection Agency.
- “Caring for Houseplants” by the University of Missouri Extension.
My name is Diane M Lewik, and I am the founder of this website. I am a degree holder in plant biology from the University of California – Berkeley. Over years, I have cultivated a vast collection of succulents and I have learned a great deal about how to grow and care for these unique plants.