Disadvantages
- Unlike organic mulch, rubber mulch does not enrich soil or increase soil biodiversity through decomposition
- Some recycled varieties may leach chemicals (some toxic) which are harmful to plants
- Rubber mulch, like some organic mulch, is a hazard if ignited.
Although rubber mulch is generally safe, recycled tire rubber leachates do contain certain minerals and compounds which may cause concern in high concentrations. Recycled tire mulch can contain trace amounts of various minerals from the tire manufacturing process and other chemicals that may have been picked up during the tire's service life.
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