Nowadays, you can buy a landscape mulch from just about anywhere. But do you know if it will add construction materials, toxic or hazardous debris. “Focus on Organic Mulch” by the Department of Ecology, State of Washington, provides information on landscape mulch for homeowners and gardeners.
Organic mulch should have the following qualities:
Pleasant, “earthy” or “woody” smell.
Uniform shape.
Particle size between 1⁄2 and 3 inches.
Quality organic mulch should not contain large amounts of:
Stones, metals, glass, plastics or other solid waste. • Chemical contaminants like petroleum residues.
Heavy metals like cadmium or lead.
Viable weed seeds.
Pesticide and herbicide residues.
Plant, animal and human pathogens.
What questions should I ask to help me identify a high-quality organic mulch?
If the product label or information sheet does not give enough information or if you cannot inspect the mulch, here are some questions you may ask to help identify a quality mulch:
What materials were used to produce the mulch and where did they come from? Diseased trees, pressure treated-wood, composite wood or painted pallets may add unwanted diseases and chemicals to your soil.
Does the bagged mulch have large amounts of physical contaminants such as glass, metals or plastics? Mulch containing these materials could damage your plants.
Does it have an unpleasant pungent, sour or oily smell? “Sour or acid” smell may indicate mulch with toxic substances that are produced under anaerobic conditions. Oily smells may indicate petroleum residues. If a mulch product smells bad, it may damage your plants
If you’re looking for mulch for your next landscaping project, there are a variety to choose from. From organic mulch in a variety of sizes, to inorganic such as river rock, granite, and marble chips. Each one can make a significant impact on not only the landscape’s appearance, but also the quality of your soil.
