When inspecting your garden beds, do you notice any exposed soil? If so, it’s time to consider adding mulch. Mulch forms a protective layer over the soil, maintaining moisture, suppressing weeds, and regulating soil temperature around plants, including uncultivated areas. However, improper use can harm your garden.
The Right Mulch Selection
People use various materials for mulching, including gravel, plastic sheeting, and shredded tires, as well as organic options like compost, pine needles, shredded bark, hay, straw, and wood chips. Each type offers different benefits.
Gravel and stones help reduce weeds and retain moisture but can impact plants differently than organic mulch. Stones absorb heat, potentially scorching plants and roots. While gravel removal is tough, it’s recommended in fire-prone areas as organic mulch burns easily.
Shredded tires should be avoided. Crumb rubber contains volatile organic compounds, lead, and heavy metals, leaving behind chemicals in the soil long-term, unless you replace the affected soil layers.
Plastic sheeting might offer benefits, but its eventual disposal in landfills contributes to microplastic contamination. Natural materials like shredded bark, wood chips, straw, and pine needles are preferable as they enrich the soil while decomposing.
Arborist wood chips, produced by tree pruning crews, are an excellent mulch choice. They allow you to see their makeup and transform into rich humus over time, nourishing plants. Wood chips hold moisture longer than other mulches.
Shredded bark mulch is also useful, performing similar functions as wood chips. However, it absorbs less moisture and might wash away during heavy rain.
Avoid Dyed Mulches
Dyed mulches are unadvisable. While high-quality dyes in black, brown, or red mulches are usually nontoxic, the base material often comes from recycled wood of questionable origin, possibly containing arsenic.
Cheaper dyed mulches may utilize harmful pigments, presenting more risks than savings. If you choose dyed mulch, keep it away from food crops. Mulch should be 3 to 4 inches deep around plants, ensuring it does not touch trunks or stems to allow air circulation, preventing trapped moisture and rot.
The practice of ‘volcano mulching,’ where mulch is heaped against tree trunks, suffocates trees, leading to decay and death. Proper mulching exposes and maintains the trunk base.
Best Timing for Mulching
Apply mulch after frost danger has passed but before weeds appear. Early mulching traps cool temperatures, slowing plant growth. Delaying risks soil erosion, weed growth, and moisture loss. Mulch also adds a tidy appearance to your garden.
For advice on effective gardening, Jessica Damiano offers regular columns with The Associated Press and publishes the Weekly Dirt Newsletter. Subscribe for tips and insights.