Finding mold on the soil of houseplants can be a little alarming – after all, mold is usually a sign that something has gone past its best. On a houseplant, this isn’t necessarily a cause for concern, but you should take steps to keep your plant healthy and avoid the side effects that can occur with moldy soil.
Mold is something that can happen to all kinds of houseplants, even the best houseplants for beginners. Understanding why it happens to a houseplant is half the battle when it comes to both treating mold and preventing it from happening in the first place. There are simple steps you can take to remove mold from plants, but if the problem persists, you may want to take more serious action.
Ignore the symptoms and it could be the death knell for your houseplant, so learn how to treat mold on houseplant soil with our guide from the indoor gardening experts.
How to Get Rid of Mold on Indoor Plant Soil
Mold on houseplant soil doesn’t mean your plant is dying – it’s largely related to the amount of moisture in the soil. Here’s a hint: it’s too humid.
“If you notice mold on your houseplant’s soil, it’s not the end of the world,” says Naomi Robinson of Houseplant Authority (opens in a new tab). “It usually appears due to the potting soil being kept too moist, either due to overwatering, poor drainage, or a combination of the two.”
Get advice on how often to water houseplants. Additionally, organic matter, such as decaying dead leaves, can also create the perfect environment for mold to thrive.
1. Move it to a new location
Take action when you first notice mold on a houseplant’s soil to ensure your plant stays in top condition. Before you consider repotting the plant, first see if a change in location would help.
“If the mold isn’t too bad, you can try putting the plant in the sun,” suggests Matt Eddleston, founder of Gardening Vibe. (opens in a new tab). “It helps the soil dry out and kills mold at the same time. Removing rotting leaves and the top layer of soil with mold also helps get rid of the problem.
2. Change the floor
“If not, remove as much moldy soil as you can,” says Brody Hall of Indoor Nursery. (opens in a new tab). “Indoor gardeners can do this by gently scraping the soil off the roots using their fingers, a small paintbrush, or an old toothbrush.”
“Clean your plant’s container when you do, ideally with bleach, to make sure you don’t accidentally pass contamination on to new soil,” adds Naomi Robinson of Houseplant Authority.
3. Check the rest of the plant for mold
“You should also check your plant’s roots for rot when changing soil, so that any affected parts can be cut off to prevent them from spreading,” says Naomi Robinson.
Check that the mold has not spread to the stem or leaves of the plant. “If the mold has already spread to the plant itself, you may need to cut off the affected leaves or stems,” says Stephen Webb of Garden’s Whisper. (opens in a new tab).
4. Treat the floor against mold
Changing the floor should solve the problem, especially if you take steps to prevent the mold from reappearing as shown below, but if the mold persists despite your best efforts, you can also try a treatment to kill the mold.
“If the infestation persists, a commercial fungus spray will do the trick,” says Brody Hall. “Or, if you want to stick with a natural product, use a pinch of cinnamon.” It may sound strange, but cinnamon has natural antifungal properties that are an effective solution against mold.
Will mold on the floor harm my houseplant?
By itself, mold on your houseplant’s soil is not a direct health risk, however, it is a sign that your plant is experiencing less than ideal conditions.
“In most cases, however, mold on your houseplant’s soil isn’t the worst problem that can happen to an overwatered plant, although it’s a sign that you need to make some adjustments,” says Naomi Robinson. “It’s mostly to prevent the situation from developing into full-blown root rot, which can kill your plant.”
Mold can also be the source of another common problem with houseplants: gnats. “If you have soggy moldy soil from standing water in your pots, you’re creating the perfect midge attractant,” says Angelia Daugirda of Organic Plant Magic. (opens in a new tab). Mold is the perfect habitat for the nests of these annoying household pests.
How to prevent mold from reappearing on the soil of houseplants?
“To avoid mildew (and all that can go with it), review your watering schedule to make sure you’re only watering your houseplant when needed,” suggests Naomi Robinson of Houseplant Authority. “You can also check that the soil you are using is sufficiently well drained.”
“To avoid overwatering which will cause mold to reappear, make sure the top 1-2 inches of soil dry out completely between each watering,” suggests Ayelet Faerman of houseplant delivery brand VerdantLyfe. (opens in a new tab).
You can also try the cinnamon trick when repotting your plant to ward off mildew. “Sprinkle a natural antifungal such as cinnamon or baking soda on the soil or add them to your potting mix,” suggests Matt Eddleston.
Keep the soil airy and drier by also moving your plant to an optimal location. “Once you’ve removed all the moldy growth, keep the potting mix dry and well-ventilated to prevent mold from returning. This may mean watering your plant less often or moving it to a brighter spot,” suggests Stephen Webb.
Finally, to prevent mold in the soil of houseplants, it is essential to use a healthy, sterile commercial potting mix.