If you find what looks like white or gray mold inside a newly opened bag of organic soil, don’t be alarmed. It’s actually a good thing! It proves there is life in the soil. Much of the success of your plants depends on the health of the microbial community in the soil they’re planted. During the composting process, we encourage the growth of some beneficial microbial species in our soils. Some of these species are fungi, they help your plants by eating any decaying organic matter and making the nutrients in it available for plants.
The white or gray “mold” is a Saprophyte, which is what is naturally found on the forest floor. They play an important part in the ongoing process of decomposition of organic matter – just like in the forest. The presence of saprophytes is an indication of plenty of nutrients which help aid in pest and disease resistance and healthy plant growth. When the moisture content inside a bag of soil becomes higher than normal – perhaps due to a few days of rain – these fungi will gather around the inside layer of the bag. It is not harmful to humans or plants. Once the bag is opened and the soil contents are exposed to sun and air, the saprophytes will disappear.