Mother Nature has been mulching and composting for billions of years. By recycling organic material, she has provided a healthy environment and a food supply for every living thing. To successfully manage our own little piece of the Earth, we can all benefit from her example

Mulching Basics

Mulch is a material spread on top of the ground to benefit soil and plant health, and make landscape maintenance easier. Wood chips, leaves, grass clippings, wood shavings, and compost all make good mulches.

Mulching Benefits

  •   -Prevents soil compaction and erosion
  •   -Suppresses weeds
  •   -Captures and retains soil moisture
  •   -Protects plant roots and crowns from extreme heat and cold
  •   -Protects and stimulates microbial activity in the soil
  •   -Adds nutrients to the soil as they break down

Mulching Guidelines: Make the Best Use of Mulch Covers

  • -Mulch all areas that are not in grass or thick ground cover.
  • -Trees and shrubs benefit from mulch spread at least as far as their outermost branches (the “dripline”). To prevent root strangulation, diseases, and pest infestation, avoid piling mulch against tree trunks.
  • -Use a layer of coarse mulch 3 or more inches in depth for weed control.
  • -When converting grassy areas to mulch, smother the grass with a thick layer of cardboard or newspapers rather than kill it with chemicals. Some hardy grasses must be rooted out for successful removal.
  • -Blanket perennials with several inches of shredded leaves, pine needles, or other fine mulch material to protect them from winter cold.
  • -Use long-lasting mulches (wood chips, shavings, evergreen needles) for trees and shrubs.
  • -Spread mulches under annuals after they are well established (4 to 6 inches tall).
  • -Water the ground thoroughly before and after applying a mulch cover.
  • -Never rely on a rainstorm to water in your mulches. In many cases, the rain will fall too heavily and quickly, and some of your mulch may run off into the storm drain and local creeks.
  • -Never mulch with diseased or insect-infested yard trimmings.

Mulch Application Guide

Mulch UseMaterialThicknessNotes
Top Dressing for Lawns Compost 1/4 to 1/2 inch Sifted through 3/8"-inch mesh or finer screen; apply especially after aerating or re-seeding, then water in.
For Annuals and Perennials Grass clippings 1/2 to 1 inch Do not mulch with herbicide-treated clippings or hay that has been treated with the persistent herbicide picloram. Can use unshredded leaves on perennial beds in autumn.
Shredded leaves and stalks 1 to 1-1/2 inches
Compost 1 to 2 inches
Old straw 1 to 2 inches
For Shrubs and Trees Wood or bark chips 2 to 6 inches 2 to 3 inches for fine chips; up to 6 inches for large chips (more than 1 inch in length). Coarse shavings only. Sawdust can bind up soil nitrogen. Coarse compost is best.
Wood shavings 1 to 2 inches
Compost 1 to 3 inches
For Erosion Control Wood chips or coarse compost 2 to 4 inches 2 to 4 inches over any area without cover; 3 to 4 inches on slopes.

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