Q: We live in an area with lots of trees, so my problem is moss growing in the lawn. When we tear it out, it always comes back. How do I get rid of it for good?
—Mike Leibensperger, Jim Thorpe, Pa.
A: Roger Cook replies: How much do you love your trees? Your yard is telling you that there's too much shade for grass to compete successfully against moss. If you really want a lawn there, either cut down some trees or prune them aggressively to let in more light.
Also, test your soil. Moss loves acid soil, so you may need to add lime to "sweeten" it. That will encourage grass and discourage moss.
Here's another approach, if you can live with less lawn: In those areas where the moss is thickest, plant a shade garden, using shrubs, perennials, and ground covers that tolerate the existing conditions. In that setting, your moss might actually be a nice ground cover. You could also add some large rocks and maybe even a bench where you could sit and cool off after mowing the healthy part of your lawn.