Preventing Moss in a Shady Lawn
Q: Parts of my lawn can be extremely soft when wet, and when I cut my grass recently I left deep ruts across the softer parts. This didn't tear up the turf or anything, but the ruts are un-sightly. What can I do to repair this damage?
— Chuck, Cordova, TN
A: Roger Cook replies: First, let's talk about preventing further damage. The obvious advice — don't mow when your lawn is wet — will not only prevent the rut problem but will give you a better cut too. If the lawn is wet so often that this regularly interferes with your mowing schedule, have a landscape contractor take a look. You probably have a drainage problem that needs attending to.
Now on to fixing the ruts. A lot of people tackle this the wrong way: by filling the ruts in with dirt and then seeding the area. But filling doesn't relieve the compaction, and the new grass never quite blends with the surrounding turf.
The best way to fix ruts is to loosen the soil. For shallow ruts no more than a few inches deep, take a spade fork and sink it into the ground alongside the rut at a 45-degree angle. With the fork's tines buried under the bottom of the rut, gently push down on the handle and lever the sod up about 1 or 2 inches above the surrounding area. Then remove the fork and let the sod settle over time to a level that's even with the neighboring lawn.
Ruts more than 4 inches deep have to be treated differently. Using a lawn edger or a spade, make a lengthwise cut through the grass at the bottom of the rut, and use a fork to fold back the sod on each side of the cut. Now, loosen the soil in the rut by turning it over with a spade, leaving it an inch or two higher than the undisturbed soil. Add more soil if necessary. Then flip back the grass, pat it down lightly, and water the area. If you do this right, no one will ever know the ruts were there.
One caution: Even if the ruts aren't deep, proceed carefully if you have an underground irrigation system. One misplaced fork tine or shovel blade could put it out of commission.