The best way to effectively and permanently control moss in the lawn and garden is to correct the conditions that are favoring moss growth.  Moss grows better than most types of grass in areas with heavy shade, poor drainage, and compact soils (Douglas, 2000).

• Mosses are often found in cool, shaded areas of the lawn where they are more competitive than grasses. The following physical control methods can help prevent and control moss growth in shady areas.
• Trim shrub and tree limbs that create shady areas on the lawn.
  
• Complete removal of shrubs or trees may be needed in areas that receive less than 3-4 hours of direct sunlight or 6-8 hours of filtered sunlight. This is the amount of sunlight that is required for most grasses to grow well (Douglas, 2000).
  
• Mow at the top of the recommended mowing height for each grass species. In general, no more than 1/3 of the top growth should be removed when mowing. This will encourage deep rooting and maximum leaf surface area, which will allow the grass to absorb more sunlight (Scott and McCarty, 2000). 
  
• A shade-tolerant grass, such as St. Augustine grass or fescue, can be planted in partially shaded areas (Everest, 2000).
  
• Instead of grass, shade tolerant ground covers can be planted in shady areas in the lawn. Two examples include pachysandra and myrtle (Vinca minor) (Douglas, 2000; Scott and McCarty, 2000). Do not use invasive species, such as English ivy.
  

Excessively wet soils can promote moss growth because mosses grow better than grass in wet, poorly drained soils. Some physical control methods that target excessive moisture include:

• Watering the lawn only when it is needed. Regularly scheduled watering and automatic watering systems will often over-water the lawn, especially in shaded areas (Scott and McCarty, 2000). 
  
• Adding sand or soil to localized low-lying areas. This will increase the elevation. This will allow more sunlight and wind to dry the area out (Everest, 2000).
  
• Contouring or trenching wet area, which will allow excess water to be drained.
  
• Installing french drains or subsurface drainage tiles in large areas of water build-up (Scott and McCarty, 2000). 
  
• Removing thatch (dead organic matter) from the lawn, which will increase grass vigor and decrease water retention on the surface. Thatch can be removed by hand raking or with a vertical mower (Newfoundland & Labrador Agriculture, 2000).
  
• Moss growth in the lawn and garden can also be encouraged by heavy or compacted soils. Compacted soils have a decreased amount of air, water and nutrient movement, thus causing stress to the grass and allowing mosses to move in. Furthermore, the decrease in water movement can prevent water drainage in the compacted soils, thus favoring moss growth. Controlling mosses by increasing the aeration of the soil can be done in several ways.
  
• Core aeration or aerification is a process that removes cores of soil from the lawn. It can be done with a manual sod-coring tool or a power-driven core aerator and should be done every year (Scott and McCarty, 2000). 
  
• Incorporating several inches of organic matter into the compacted soil will improve the texture and draining in the soil (Douglas, 2000).

Physically controlling mosses is often used along with chemical control to increase the chance of completely eliminating mosses from the lawn and garden. Physical control methods can also be used as an effective, chemical-free alternative to chemical control. Most physical control methods are inexpensive and take only a short amount of time to implement.

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