Rubber mulch is a type of mulch used in gardens and sustainable landscaping that is made from 100% recycled rubber.
Rubber mulch generally consists of either waste tire buffings or nuggets of rubber from tires that are ground up whole, after having their steel bands removed. Almost any tire can be used to make rubber mulch, including passenger vehicle tires and large truck and trailer tires. Buffings are produced from recycled truck tire tread when the remainder of the worn-down tread is removed from the tire prior to retreading. Buffings are generally thin slivers of rubber. Nuggets range in size from 10 mm to 32 mm, or 3/8 inch to 11⁄4 inch.
Rubber mulch provides several advantages over plant material based mulches. For landscaping and gardening purposes, both nuggets and buffings insulate soil from heat, allowing a 2 or 3 degrees F higher soil temperature difference over wood mulches. Rubber mulch is beneficial for soil moisture, as rubber is non-porous and does not absorb water on its way through to the soil. It also reduces fungus growth and plant growth, and becomes a weed barrier, as weed seeds dehydrate in the mulch before reaching the soil. Neither nuggets nor buffings provide any humus to compacted soil types.