Should you remove old mulch annually?
Written by
Michael Sullivan
Reviewed by
Prof. Charles Hartman, Ph.D.When the mulch is completely removed, it destroys the amenity for soil microorganisms and disrupts nutrient cycles in soil ecosystems. Instead, replenish decomposed layers periodically throughout the year, while allowing healthy and active material to remain in place. This method maintains soil structure and encourages the growth of earthworms, which in turn build organic matter and aerate the soil.
Seasonal Replenishment
- Add 1-2 inches of fresh material over existing layers
- Mix lightly with existing decomposed mulch
- Focus on bare spots showing soil exposure
- Time applications with spring/fall garden preparation
Safe Removal Exceptions
- Remove moldy or slime-covered sections immediately
- Extract herbicide-contaminated mulch entirely
- Clear areas before switching mulch types
- Eliminate rodent-infested sections carefully
Soil Protection
- Never disturb established earthworm colonies
- Maintain fungal networks by minimizing disruption
- Preserve moisture-retaining decomposed layers
- Avoid compaction during maintenance
Healthy decomposition manifests as a dark, crumbly material that mixes with the soil surface, forming a rich, organic layer. This important humus nourishes plants and increases drainage. I lightly rake fresh mulch over those areas, without disturbing any decomposing material underneath. Over the next several weeks, earthworms will incorporate the new material in due time.
Mold conditions call for deliberate handling. Utilize a garden fork to scrape off the slimy patches without disturbing the surrounding soil; you want to scrape, not excavate. Discard contaminated material in a bag rather than composting. I then clean my tools with a vinegar solution to stop any incidental spreading of spores to healthy areas.
When switching from plastic mulch to organic mulch, remove only half of the plastic sheeting before laying down straw or leaves. This prevents soil from being exposed to the elements while still allowing it to integrate. If you are switching from one type of organic mulch to another, put the new material over the old material after roughing the surface.
Take advantage of these sustainable approaches for maintaining soil health while managing mulch. Your garden will sustain fertility with much less effort from season to season. Instead of obliterating mulch this season, just top off thin spots.
Read the full article: Mulching Vegetable Gardens: Ultimate Guide for Success
