Proper Mulch Depth

• The recommended mulching depth for organic mulches is 2 to 2.5 inches. At this depth, most mulches will accommodate the primary objectives of weed control, soil moisture conservation and temperature modification.
• Mulching depths less than 2 inches may not be effective in weed control; however, mulch applied 3 to 6 inches or more can lead to serious problems for landscape plants. A mulch that is too thick may severely reduce or eliminate drying and lead to water-logged soil, particularly during wet seasons.
• Excess mulch applied right against the trunk of trees in the landscape leads to constantly wet bark and conditions favorable for disease development which can potentially damage the tree.
• When reapplying mulch over an existing layer of mulch, bring the total depth up to 2 to 2.5 inches.
• Do not apply 2 inches of mulch with each application or soon a depth greater than 3 inches will accumulate. Some mulches break down at a much slower rate. Keep this in mind for future applications of mulch.