Pugh's Earthworks Mulching Provides Numerous Benefits Why is mulching important? Increased amounts of organic matter will improve soil tilth and drainage, increase soil moisture retention, reduce soil compaction, and attract earthworms. Because organic mulches decompose, they need to be replaced. Depending on the type of mulch used, replacement intervals vary from one to four years. If your business is ready for a new round of mulch please give us a call so we can get you on our schedule.