Why is my ChipDrop moldy? Did I get old wood chips?

As wood chips sit in a large pile, they will naturally heat up and start to decompose. As this happens, mushroom mycelium will start to grow on the wood chips and break them down. This may look like a white or green mold growing on the wood chips. There may also be a powdery substance that floats in the air when you disturb the pile. This is all normal wood chip behavior, and is actually very beneficial to your soil and garden. However, it can be very bad to breathe in this dust. We recommend that you wear a dust mask while spreading wood chip mulch to avoid breathing in too much of the dust.

If you have asthma, any breathing related medical issue, or any known allergies to wood or plant material, you should not spread wood chips in your yard. Please have someone spread the wood chips for you. After the chips are spread, wait about 2-ish weeks before you walk on them.

Read more about the benefits of mycelium and fungi in the garden.