Do you have as much moss in your yard as grass? More? Here are a few tips for getting rid of
the fuzzy green stuff...
First you should know that moss likes damp and highly acidic soil. It thrives in the shade (but it can do well in the sun, too, with enough moisture). In climates like the Pacific Northwest (where it rains a lot), it's not uncommon to have a layer of moss hiding in and suffocating the grass like a spongy carpet.
Iron sulfate is sold often as a means of getting rid of moss, however, it doesn't do anything to help your grass. If the grass doesn't get a good foothold, the moss will soon return.
The key to long-term moss control is to improve the conditions for your lawn.
Here are some ways to do that:
Shade--If your lawn is hit by shade most of the day, try to think of ways to increase air circulation and sun (maybe trim back tree branches).
Drainage--Moss likes moisture and a yard remains moist for many reasons such as compacted soil, low spots, frequent rain, or sprinklers left on too long. Try to correct the problems that are leading to too much moisture in your yard.
Soil pH--Moss likes a very low pH (whereas grasses do not). Check the pH of your soil, and if it's lower than 6.0 raise it by applying lime.
Lawn Care--Taking care of your lawn and keeping the grass healthy will go a long way in preventing moss from getting a foothold. Apply fertilizer and aerate your lawn regularly. Don't cut your grass too low when you mow (you should only remove the top third of the blade). If you get a lot of shade in your yard, plant with a shade-tolerant grass mix. However realize that some yards are just too shady for grass to do well. Instead, try digging up that grass (or whatever moss-grass combination you have growing now) and planting shade-thriving groundcovers or perennials instead of a lawn. A water garden can add a park like feel to shady yards.
Source: "Getting Rid of Moss" from Better Homes and Gardens Special Interest Publications: Garden, Deck and Landscape (Spring 2005).