Proof of Life: There May Be Mold In Our Soils

If you find white mold in a bag of our potting soil, don’t think it’s spoiled like moldy bread. Consider this white webby material the ultimate proof of life. It is an undeniable sign that our potting soils are perfectly blended to create a bio-active root environment. Even while that bag sat at the garden center, a great deal of activity was going on in our living soils, and the mold proves it. This is a rare opportunity to actually see one of the invisible organisms that contribute so much to organic plant health. Such tiny living things are literally a web of life key to all fertile soils.

Molds appear only when the bag is warm and moist inside. Such conditions actually make the mold grow on the surface of the soil because it thinks it’s underground. Once the bag is opened, sunlight and drier air forces them back to their invisible subterranean status.

This mold is a saprophyte, one of many that are naturally present in forests and bogs. When we harvest the bark and peat for our soil mixes, the molds living inside the organic matter come too. Their role is key to the ongoing decomposition of organic matter in the wild that continues within our soil mixes. These organisms also feed on the organic fertilizers added to our soil products making them more available to plants. Their interaction with fertilizers is directly related to why organic plant foods take more time to reach optimal levels than synthetic ones. In fact, patches of mold can be thickest around pockets of organic fertilizer.

Saprophytic molds act much like beneficial insects do in your garden. When aphids attack in the organic garden, bio-control is provided by hungry ladybugs that feed on them. If you use chemicals to control the aphids, you lose these beneficial predators too, leaving the door open for future infestation. This is why we do not sterilize our soils. Sterilization may yield a disease free environment, but in a short time the disease organisms will return without the saprophytes for natural control. Naturally occurring beneficial microbes in our potting soils carry this complex yet natural balance into every container you plant.

Be aware that not all potting soils will foster saprophytic molds. Insufficient nutrient content and low amounts of fine organic matter in poor quality soils cannot support them. Plants grown in such mediums will lack the many layered benefits provided by a diverse population of soil microorganisms.

Today’s backyard gardener will find that our saprophytic rich soils are the most optimal growing medium available. As the molds do their job over time, you can be sure that this soil is just growing richer in the process.