There are several reasons moss may begin to grow in your lawn. You may not have enough direct sunlight, your soil may remain wet for long periods of time or you may not have applied any fertilizer to your lawn. Whatever the reason, you will need to kill the moss and remove it. You can then plant fresh seeds to take the place of the moss that you took away.
Choose an herbicide that contains the active ingredient ferrous ammonium sulfate. This is the ingredient needed to kill the moss.
Mix the herbicide as directed on the package. Most herbicides are concentrates that need to be mixed with water. The amount may also depend on how big of a patch of moss you need to kill.
Spray the herbicide directly on the moss. As the moss begins to die, you will notice it turn brown or black in color.
Use a rake to rip the moss up and out of your lawn. This will not be hard to do after the moss is dead.
Reseed the area where the moss was with new grass seed. Water the area so that the seeds can begin to germinate and grow new grass.