What is the yellow stuff in mulch?

Answer by  JBP0430 (7)

If is often referred to as "slime mold". If your mulch is 3 inches or thicker in depth it will often time create a fungus that appears to be yellow.

Answer by  fordguy777 (346)

This yellow substance is called "slime mold" and is very common with yard work especially in the warmer months of the year. Typically when it gets warm out the fungus can bloom within the mulch and cause these ugly yellow patches. If there is more than 2 inches of mulch on the ground this can be caused.

Answer by  cwalker0 (190)

This could be a number of things but it is probably a fungus that is esential to the breaking down of the waste.

Answer by  champaign9497 (11977)

It could be alot of things if you look on the bag you bought the mulch in there should be a phone number call it ask them.

Answer by  scyllatwo (226)

The yellow substance that sometimes appears in mulch, no matter type it is, is actually a fungus that grows on any wood in the mulch. Mulch is made from bark of a tree, not the wood. So if wood gets into the mulch mixture, a fungas can, and does, form.