Extreme moss growth in my back yard

Asked May 3, 2018, 12:49 AM EDT

Over the past 2 years my back yard has been overwhelmed with the moss growth (roughly 50%). I have applied a moss killing chemicals to suppress this, but it just keeps coming back. I have done the soil test and have sufficient amounts of phosphorus, not enough potassium and too much magnesium. I was told that I need to make sure the PH is 7, but it already almost is. It gets the same amount of water and sun for the past 10 years, but the moss was not there until about 2 years ago. What do I need to do to prevent it from growing?

Washtenaw County Michigan

1 Response

Your soil test shows the soil is neutral and healthy for growth of grass. Yes soil test says your site needs potassium but most lawns do and this can easily be addressed by use of a lawn fertilizer such as a 20-0-10 or something similar. Apply this fertilizer 2 to 3 times per year to encourage grass to grow in densely. Has the grass in this area been fertilized regularly? It is important for grass especially in shaded areas to be mowed high so there is more plant surface to absorb light. Mowing at three inches will help. For moss to be doing this well there has to be a site consideration keeping grass from growing well. First the sunlight issue. If there is less than four hours of full sunlight than it is not unusual for moss to grow in where grass is in too much shade. Use of a shade mix with fine fescue would be recommended for lower light conditions. If shade becomes too dense as trees grow there is a point where grass will not work and another ground cover may be needed. One other site consideration is water. If this area stays wet for long periods or it is watered too frequently it could be thinning the grass allowing moss to take over. If too wet and shaded it becomes hard to maintain our common lawn grasses. There are a lot of variables that can lead to moss; shade, wet sites, areas that died out due to other problems and acid soils (your soil is neutral and not a problem). If you like to discuss this more in depth please contact me at 517 7884292 and select my name from the menu. Thanks Bob Bricault