In order to obtain effective control of moss, you must consider the reasons why it began to grow in the lawn in the first place. Attempts to eradicate moss are rarely effective unless there is actively-growing turf to take its place.
Moss in lawns is usually the result of conditions that are not beneficial to good growth in turf. Moss is usually associated with shallow soils, poor soil fertility, low soil pH (acid soils), heavy shade, and excessive moisture. If any of these conditions are inhibiting turf growth, moss can and will invade the lawn and establish itself.
You should get a soil test done and determine the acidity of your growing area. I can almost guarantee that your soil is on the acidic side and will need to be treated with a good application of lime to "sweeten" it up (I prefer calpril lime.. not as messy and faster acting). You more than likely have a soil compaction problem as well and need to do a "core aeration" in the spring. Pruning back and removing any tree branches or shrubs that are shading the lawn to allow more sunlight in will also help to stop moss from growing (moss doesn't like sunlight). Good mowing practices need to be on the menu as well. Mowing a turf too low will help moss get established. Most "cool" season turf grasses should be mowed at a height of around 2 1/2 - 3". Hope this has answered some of your concerns about ridding your lawn of moss. Good luck!..
...$Billy Ray$ 24yrs...landscape profession
2yrs...turf specialist
2yrs...greenskeeper (championship golf course)
2yrs...tree & shrub technician
DPR licensed applicator (current)