Moss is a common lawn issue that is caused by moist weather conditions and poor lawn maintenance practices. Although lawn moss is not a dangerous lawn disease, as it does not kill grass, it does ruin any uniform look you may be trying for by growing in to patchy areas. Lawn moss can be killed by using chemical products and lawn fertilizers with lawn control, says Washington State University, but moss is easy to kill using proper lawn maintenance.
Break up lawn moss by running a rake over exposed areas where the moss is growing. Washington State University recommends raking out dead moss as well, so that exposed areas are clear of old moss that may inhibit new grass growth.
Aerate the lawn using a core aerator hand tool or mechanical tool. This removes plugs of dirt from the soil, eases compacted soil and improves water drainage. Wet soil that does not drain well contributes to the growth of moss, says Oregon State University.
Test the soil of your lawn using a store bought pH test. Grass grows best between a pH level of 6.0 and 6.5. If the grass pH is too low, it is acidic and will need an application of lime to raise the pH. If the pH is too high, it is alkaline and requires sulfur to lower the pH.
Fertilize the lawn using a nitrogen rich fertilizer after the lawn is aerated to increase grass growth and improve density. Use a fertilizer that is high in nitrogen, with a 3-1-2 ratio.
Spread a winter grass seed over the lawn in the fall, between September and October to increase grass density in the spring. Rye grass and fescue are common winter seeding grasses.
Prune branches from trees around the mossy area to increase light and air flow to the infected area to prevent moss growth and kill moss living in the area. Moss likes cool, wet areas to grow.