How to Edge Tree Rings

Tie garden twine loosely around the tree. Trim off the untied end between 36 and 72 feet based on the size of the ring around the tree with garden shears.

Hold onto the untied end of the twine and walk around the tree, while holding the string taut, as you spray a line along the ground with spray paint. The string will guide your hand to spray a circle around the tree at an equal distance from the trunk. Clip the twine off with the shears once you have sprayed the circle.

Dig a 4- to 6-inch deep trench around the outside of the spray-painted circle with a shovel. Make the trench 8 to 12 inches wide. Lay the dirt along the inside edge of the trench.

Fill the bottom 2 inches of the trench with sand. Tamp the base of the trench firmly by striking it in an up and down motion with a tamper.

Place the edgers at the base of the trench, end to end around the tree. The outside edge of the edgers should be flush with the outside edge of the trench.

Lay a level across the top of each edger. Tap the edgers with a rubber mallet to adjust them to sit level. Fill the inside edge of the edgers with the dirt that you removed from the trench with a trowel. Gently pack the dirt by hand.

Fill in the edged tree ring around the tree trunk with a layer of mulch. The mulch should sit approximately 1/2-inch below the top of the edgers.