The mold that is visible in your soil is likely a saprophyte -- a harmless mold -- and soil rich in organic matter often contains it, though it is usually not seen. While the mold may not harm your plants, it indicates that the environment around your plants is most likely susceptible to disease, such as root rot. Remove the mold to improve the aesthetic quality of the soil, and make some cultural changes to improve the growing conditions for your plants.
1. Scrape off surface mold and discard it. Use a spoon or knife for a houseplant. Outdoors, use a trowel or shovel to carefully scrape the mold off.
2.Till the soil in large areas with a tiller, spade or garden fork. If the mold is growing near plants, carefully use a small, hand-held garden fork that you have more control over so you do not harm the roots. For potted plants, repotting may be necessary, using fresh, high-quality potting soil. Turning the soil aerates it and relieves compaction, which may cause drainage problems.
3. Allow the soil to dry out between waterings. For plants that require moist soil to thrive, wait until the surface is dry, then water. For plants that can tolerate some dry soil, wait until the soil dries out 2 or 3 inches deep before watering. When you do water, water deeply so you do not need to water as often. In the garden, apply 1 inch of water. For potted plants, water until the water drips out the drainage holes.
4. Keep the area on top of the soil clean and free of debris. Rotting leaves and plant parts may be a haven for fungal growth. Trim nearby shrubs and trees to increase sunlight exposure, which will help keep the soil from staying too wet.
By Melissa Lewis, December 14, 2018