QuestionsHow to growTrees and ShrubsFeedingMulch Smell 0 Vote Up Vote Down ross tobin asked 15 years ago I put mulch out and the smell is quite powerful – i think it has gone sour as was bought from DIY chain store – how long will the smell stay and any tips to get rid of the smell? 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 6 years ago That should not happen … It must not have been prepared properly, take it back or leave and the smell will soon disappear.