Plant soil is organic matter and is susceptible to white mould growth. This mould is not harmful to plants and disappears on its own once it completes its life cycle.
White mould growing on plant soil surfaces is known as saprophytic mould. This type of mould is common around woody plants. While saprophytic mould is harmless to plants, it is often unsightly.
Saprophytic mould causes a white mouldy growth on the surface of plant soil. This mould often resembles melted marshmallows and has a thick consistency.
Saprophytic moulds on plant soil will disappear on their own. However, it is easily removed from plant soil by scraping it off and discarding it. Chemical controls are not required for saprophytic mould.