Moss in is lawns often caused by poor drainage, soil compaction, excessive shade or mowing too close. Poor drainage and soil compaction can be improved by piercing the entire area with the tines of a garden fork. This can be done at any time from autumn to spring, but choose a dry day while the soil is moist but not waterlogged. Afterwards brush in a sandy top dressing to loosely fill the holes. Ready made dressings can be bought from most garden centres.
The next step is to spread a moss killer across the area. Wait until the grass begins to grow again in mid spring. The dead moss can be removed with a spring tine rake about 2 weeks later. Collect it up and compost it. If moss persists, another application can be undertaken in mid-summer so long as the ground isn’t too dry.
It is worth feeding your lawn after the moss has been removed as this will speed its recovery. Large bare patches can always be reseeded. Finally, mow the grass a little higher than usual. Moss can rarely compete with well established, healthy grass. It is well worth establishing an annual lawn care regime as this will help reduce the problem in future.