Why is moss present?
Although not quite a weed in the broadleaf/grassy sense, moss can be a nuisance in a lawn and people often want to know how to get rid of it. However, before you control your moss, you must understand why it is present.
Moss loves shade, moisture, and poorly drained or compacted soils. It will tend to fill in areas where grass has weakened and cannot grow. Moss is simply filling a void.
How do I kill it?
There are plenty of products available for killing moss. Some fertilizers contain moss killing agents and products containing ferrous sulfate and ferrous ammonium sulfate will work. Algae and moss killing soaps are also available under various brand names.
My favorite moss killer is simple Ultra Dawn dish soap mixed with water. It's safe, cheap, and it might already be in your house. A couple of applications of the soapy-water solution will have the moss drying up, turning orange and dying.
How do I keep moss from coming back?
Like most weeds, the presence of moss is usually an indicator of a larger problem. Unless the underlying issue is addressed, the presence of moss will likely be a recurring headache.
Examine the yard to ensure preventive measures have been taken to reduce the conditions favorable to moss. Have your soil tested and adjust the pH if necessary. Selectively prune trees to increase airflow and sunlight. Improve drainage where necessary with core aeration, and repair the area the same way you would repair a bare patch in the lawn.
What else can I do?
If all this moss control seems like a little too much trouble there is an alternative. Embrace the moss. It's not easy or even recommended to try and grow grass where it just does not want to grow.
Moss makes an excellent ground cover. It's look and feel are intriguing and pleasing to the eye, and it's a nice alternative to grass. Conditions might suggest that it would be easier to encourage the moss and take measures to discourage the turf instead.