What to do when mould appears in the substrate of your potted plants?

If you're one of those people who have always had plants at home and have taken care of them all the time, you've probably stumbled upon a white powdery mould on your plant's soil, especially on indoor plants that are potted in a pre-mixed soil.

And although it's normal to be alarmed by seeing this alteration in your plant, it's not necessarily harmful (depending on how far it has spread through the soil), that's why I invite you to keep reading this article so that you can learn how to act when mould appears on the soil of your potted plants.

what is the cause of white mould in the potting soil?

Before anything else, it's important to know that not every time you see a white layer on top of the soil of houseplants is due to mould. In some cases, a white layer can also form because the water used for irrigation has high levels of salts and calcium, and the plants absorb only the necessary nutrients and the rest remains on the surface, which is why a white layer forms on top of the soil. When this happens to your plant, you should remove the top few centimeters of soil and thus solve this issue.

white layer

Now, if the white layer is moist, it's white mould on the plant soil. It's not very difficult to identify by the way it spreads, if it colonizes the entire soil or even the plant, then it's definitely mould.

ideal environment for mould

The common cause of mould appearing in soil is when the soil mixture with nutrients becomes an environment that favors its growth and development. It will appear in the soil when the temperature and humidity conditions are high, which combined with the soil nutrients will promote mould growth.

saprophytic moulds

There may also be saprophytic moulds present, this type of mould only feeds on dead plant material, so it doesn't pose any danger to the plants or people. In the worst case, it can cover a large area and thick layer of this mould on the soil, making it difficult for water to pass through and be absorbed when watering the plant, in this case, it's necessary to remove the layer of mould.

how to eliminate white mould from your plant soil?

If you don't know what type of mould is appearing on your plant's soil and it's spreading too much or causing bad odors, the best thing you can do is to remove it completely. Many times, these moulds in the soil can be harmful and even attack the plants.

mould in the pot

If the mould is found in the pot itself, a thorough cleaning is necessary. In this case, you should start by removing the soil crust and shaking it to remove as much soil as possible from the roots. If they are severely affected by mold, it's also recommended to prune them. After finishing this, you'll need to use new soil and a new pot or thoroughly disinfect the infected pot.

mould on surface

On the other hand, we may have the case where the mould is not evenly distributed throughout the soil (on the surface), and for this, it's recommended to use a fungicide. Eco-friendly fungicides work very well. For example, you can prepare a mixture of milk and water in a 1:9 ratio, and spray it on the soil or affected area daily until the mold disappears.

During treatment, it is important that the pot is moved to a well-ventilated area, as the less humidity there is, the simpler it will be to remove mould from the substrate.

how to prevent white mould in plant substrate?

Preventing the appearance of mould on plant substrates is as simple as providing conditions that mould cannot tolerate, such as: ventilation and low humidity. It is clear that the idea is not to stop watering plants, but to wait until the substrate has dried slightly before watering again will be of great help.

Regarding plant ventilation, it is sufficient to leave the plant in a location where there is natural air circulation. However, this practice is not tolerated by all plants, in case your plant does not tolerate air currents, it is recommended to manually remove the top layer of the substrate without damaging the roots, so that the substrate can be aerated in this way.

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