What House Plant Fungus Is Harmful and What Isn't: An Ultimate Guide

December, 2023
Darren Spalding

So you have a house plant? Great! Plants are great for your home as they can reduce stress and create a positive atmosphere inside. However, most people don't know that some plants also grow fungus. Yes, it's true: there is such thing as "houseplant fungus." This usually isn't what you want or expect to see on one of your healthy green friends (and it often has the opposite effect than what we just mentioned!). Luckily, this article will give you all the information you need about when to worry and when not to worry about whether or not your plant has grown an unwelcome guest in its soil.

How to prevent fungus

  1. Poor aeration or ventilation can exacerbate fungus growth. Make sure your plant is spaced properly to provide it with a good flow of air, and use an oscillating fan if necessary.
  2. It’s much easier for plants to dry out in the morning than at night. The fungi first pop up when moisture is present for a long time, so water early in the day, and not at night.
  3. A great rule of thumb to avoid overwatering plants is to touch the soil at least two inches below with your finger. If it’s moist, don’t water right now. Other watering tips are available in our essential guide!
  4. Make sure your planter has sufficient water drainage points so your plant does not have too much moisture. If you do not have a hole in your planter, keep the plant in an open nursery pot inside it to ensure that it receives ample watering.
  5. One helpful way to deter fungus from taking over your plants is baking soda. To make the homemade solution, mix together a teaspoon of baking soda and 1 gallon of water. Dilute it thoroughly before applying to all plants in a small area and test out on one leaf first for any adverse effects.
  6. Remove any leaves or dead plant parts from around the living plants as soon as possible!
  7. It is important to consider the specific needs of your species of houseplant when placing it in your home. The better maintained it is during both watering and outside maintenance, the more resistant it will be to house plant fungus.

Sooty Mold

Sooty mould develops on the parts of your house plants that are covered by honeydew secretions from pests like whiteflies, aphids, and scale. Sooty moulds can stunt plant growth or cause leaf drop because they block sunlight and decrease the ability to photosynthesise.

How to deal with Sooty Mold

The first step is to identify which pest has caused your plant's sooty mould. Once you have done that, it will be easier for you and a professional to nip the problem in the bud before things get worse!

Your next option is to trim off any infected leaves with scissors or pruners if they are small enough. Make sure not to cut healthy parts as well when taking care of this fungus-ridden houseplant!

One easy way to get rid of sooty mould is by wiping the plant with a damp cloth.

To make your own natural disinfectant, mix together some water and lemon juice in a spray bottle - then spritz it all over the plant's surface! Allow for five minutes before rinsing off any visible residue or spots.

If you're having trouble getting this fungus under control, talk to a professional gardener about what they recommend. They will be familiar enough with various species' requirements that they'll know how best to take care of them while also tackling fungi problems at the same time!


Mushrooms growing on the surface of houseplant soil are often harmless but can be a problem if there are pets or small children in the household. If this is the case, remove them!

Mushrooms that are poking out from the top of your plant's soil can be a sign of overfertilization or too much watering. Try to reduce these things and see if they go away.

If you have pets or small children in the house, it is best not to touch mushrooms because they could harbor bacteria such as salmonella on their surface - so remove them!

An easy way to get rid of mushrooms growing near a stem is by using rubbing alcohol. Simply pour some onto the mushroom until it slides down towards the base where it roots and repeats for any other ones nearby!

To avoid fungi growth altogether, use the sterile potting mix when filling new containers with plants. It will help prevent fungus spores from growing.

Powdery Mildew

Powdery mildew is caused by airborne fungal spores and can look like a light dusting of flour or powdered sugar over the leaves. If left untreated, powdery mildew will multiply and spread to the rest of the plant, causing it to weaken and drop leaves.

How to deal with Powdery Mildew

There are two types of fungicides available for dealing with powdery mildew - systemic and contact. Systemic fungi can be applied to the soil or sprayed on the leaves, while contact fungicides should only be used on plants that have been watered in order to avoid runoff issues. If you need help choosing a type of fungicide, talk to a professional at your local garden centre!

In order to prevent fungus growth from taking over your houseplants, try using baking soda as an effective deterrent when mixed together with water. To make this homemade solution, mix together one teaspoon of baking soda and one gallon of water before applying it all around an open nursery pot full of lant. Dilute it thoroughly first before spraying it onto all

White Mold

White fungus growing on the surface of the soil is a harmless saprophytic organism, but it may be a sign that your plant's needs for light and ventilation are not being met. It will compete with your plant for nutrients and you don't want to breathe in this mould either!

How to deal with White Mold?

If your plant has white mould on the surface, you can break it up with a soil dibble or long-handled spoon. Be careful not to damage the roots!

White fungus growing near a stem is called bacterial rot and needs to be removed immediately before it causes any lasting harm. This means taking care of each individual spot as soon as possible so that bacteria doesn't spread further into the root system.

To prevent this type of mould from coming back, make sure that pots are draining well and have good air circulation - both things will help reduce humidity levels in most rooms too!

Grey Mold (Botrytis)

Gray Mold grows in large, greyish-tan areas on leaves, stems or flowers and is often found around soil that is a little too wet. The spores are dust-like and fuzzy with an orange hue and prefer damp conditions like those found near a broken leaf or stem. If you see any of these signs appearing at the plant's older parts when new growth starts to occur it is important to cut away the affected area ASAP.

How to deal with Grey Mold

Grey Mold is a fungus that needs to be managed quickly. If it has infiltrated the plant so deeply as to cause wilting or browning then it may need help from a professional. However, if you catch it early enough on healthy parts of your houseplant just cut away any affected leaves and stems before they spread further!

Nowadays there are fungicides available for dealing with Botrytis outbreaks - some of which can also be used in hydroponic systems such as those found in greenhouses too (talk to someone at your local garden centre). These will stop mold spores from growing new colonies by inhibiting their ability to produce fertile cells needed for reproduction.

It's important not only to take care of individual plants but an entire room in order to maintain healthy levels of humidity. Try using an air conditioner or dehumidifier if necessary!

Stem, Crown, and Root Rot

Stem, Crown and Root Rot is caused by fungal mycelia which live indefinitely in soil, coexisting with houseplants. If you overwater your houseplant and air circulation isn’t enough to dry it out, especially in a cool environment, the fungus can suddenly and quickly multiply and take hold of the plant. If you see rot above the soil, you may also have root rot; read our essential guide to watering to learn how you can deal with root rot and improve your watering habits.

How to deal with Stem, Crown & Root Rot

If your houseplant is suffering from any of these types of rot, you need to cut away the affected stems and roots as soon as possible. Fungicide can be applied on a regular basis after this initial clean up so that the plant never comes in contact again with disease-causing soil or water.

The best way to prevent stem, crown and root rot? Prevention! Make sure not to overwater plants - especially if they are situated where air circulation is poor (e.g., near curtains) and make sure new pots have drainage holes before planting them up into fresh potting mix too!

Fungal Leaf Spots and Rust

When spores in the air find a wet, warm leaf to stick to and form a small lump on that leaf, they eventually grow into larger lesions on leaves. Leaf spots are caused by fungi like mildews or rusts and can be yellow, tan, brown/reddish, or black with either a yellow rim around the spot or irregular borders. If you’re not treating this disease your plant could die entirely.

Rust is more common in outdoor gardens than houseplants, but it’s worth keeping an eye out for.

Rust spores will form red, bumpy spots on the surface of leaves and reddish-orange blisters on their undersides, as well as cause leaves to drop.

How to deal with Fungal Leaf Spots & Rust

If you want to treat your plant with a fungicide, make sure that the spot is less than a quarter of an inch in diameter. If it’s larger then wait until after leaf fall and apply the fungicide carefully (sparingly).

The best way to prevent Leaf Spots & Rust is not only by making sure your houseplant has enough air circulation but by avoiding watering when leaves are wet. It's also important to avoid overwatering as well - so keep an eye on soil levels!

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