Sour or toxic mulch smells horrible, usually with an aroma of vinegar, ammonia, silage or rotten eggs. This is caused by a lack of oxygen in manufacture or storage, leading to the buildup of hydrogen sulfide, methanol or acetic acid during decomposition.

How do I stop my bark from smelling?

Give it a few good soakings with a hose, and let the sun/rain dissipate the smell. The first few weeks as your kids play in the area the smell will come up again with their disturbance, but not nearly as strong. It will still smell if you sniff a handful a month or two later, but within the year it will gone.

Does bark chipping smell?

Sour mulch can smell like vinegar, ammonia, sulfur, or silage, whereas good mulch smells like freshly cut wood or earthy like soil. This mulch may also feel very hot to the touch. Sour mulch occurs when the materials used to make mulch are stored in piles that are too large.