If you notice a white or yellow substance on the top of your houseplant soil, it may be that one of the many varieties of mold or fungus has found a home in your houseplants.
Mold and fungii are spread by spores. By the time you see the mold or fungus on the surface of the soil, millions of spores have already been produced.
When a houseplant has fungus growing on the soil, it should be separated from the other houseplants. The spores are very tiny. It only takes a small disturbance to send the spores airborne where they will move to the other houseplants nearby.
While many molds and fungii are actually beneficial to plants, they may be toxic to people. Great care should be taken with mold. They may also cause reactions in people with allergies or sensitivities to molds. It is suggested that you should use latex gloves and a mask when dealing with mold and fungii.
Several things can be done to reduce or get rid of an infestation. These methods will need to be used if changing the plant’s growing environment do not control the fungus outbreak. Fungus likes darkness, heat, high humidity and stagnant air. Fungus may disappear if we move the houseplant to a brighter location, a cooler location, a drier location or a location where there is more air movement.
1. You can carefully remove the top 2 inches of soil where most of the spores would be located. You should move the plant outdoors, if possible, to do this. Remember, disturbing the soil will send the spores airborne and they will spread around the room. Then replace the soil with sterilized potting soil.
2. If the fungus returns or the infestation is extensive, you can repot the houseplant. This should be done outside, if possible, so that the spores will not be spread around the room.
Take the plant out of the pot and remove all of the soil from around the roots. The soil may be washed from around the roots taking care not to damage the roots. Before replanting, the pot should be washed with hot water and bleach to get rid of the mold and spores. Then replant in the pot with new sterilized potting soil.
3. Another method that works is to use a weak vinegar solution. The mold or fungus does not grow well in acidic soil, but be careful as your houseplant may not either.
Mix 1 part vinegar with 10 parts water and spray the affected area. Spray enough that the affected area is totally damp but not so much as to moisten the soil down more than an inch.
Spray once between waterings and don’t water for a day or two after watering to allow the vinegar to kill the fungus. This will need to be repeated as additional spores already in the soil start to grow.