Organic mulch helps conserve soil moisture. A 2-4 inch layer of organic mulch reduces soil moisture loss from evaporation, moderates soil temperature extremes, reduces competition from grass and weeds, improves soil aeration and structure, adds organic material to the soil, and will help prevent lawnmower and weed whip damage to the trunk. Apply organic mulch within the dripline, to a depth of no more than 4 inches.
A layer of mulch deeper than 4 inches may cause problems with gas exchange. Leave a 3-4 inch space between the mulch and trunk of trees. If the mulch comes in contact with the tree trunk, decay causing fungi and insect pests may cause serious damage to the tree. Mulch materials may include wood chips, bark, leaves and evergreen needles.
