In Harmony Sustainable landscapes, Lawn Care, Moss

Moss in the lawn can be managed if you address the underlying causes.

Are you fighting moss in your lawn? Moss invades lawns when the grass does not have the right conditions to be healthy.

If the lawn is healthy and in a location that favors grass, it can outcompete moss. Still, western Washington provides an ideal growing environment for moss, so you may not be able to banish it entirely.

In Harmony’s lawn care services will improve the health of your lawn. But if your lawn has underlying problems or it is in the wrong location, moss will grow better than grass will. You need to address the root causes.

Your lawn may have one or more of these problems: 

  • Infertile
  • Low in calcium and/or high in acidity
  • Wet
  • Compacted
  • Shady


Your lawn needs nutrients to grow more thickly so it can compete with moss and weeds. May is a great time to fertilize your lawn. Choose an organic fertilizer with at least 50% nitrogen. It will feed your lawn slowly over time and is less likely to run off into nearby streams. Be sure to read the package and apply the right amount. Mulch mowing can supply a quarter to half of your lawn’s nitrogen needs.


Many soils in western Washington are acidic and/or low in calcium. Lawns don’t grow well in these conditions. You can apply lime to remedy these problems. It won’t kill the moss, but it will help your lawn grow more thickly. Choose Dolopril lime, which contains both calcium and magnesium.


If you have a problem with drainage, you will also have problems with moss. Is a down spout draining onto your lawn? Is the lawn lower than your driveway or sidewalk? Do you have low spots in the lawn that tend to be wet? And are you overwatering your lawn? Lawns do better with deep, infrequent watering.


If your soil is compacted, it’s tough for grass to grow. Aeration will help your lawn roots get the air and water they need. It improves the uptake of water and fertilizer. And it reduces water runoff and puddles. Overseeding fills in any thin spots to help your lawn compete with moss.


Grass needs regular sunlight to grow well. It doesn’t tolerate heavy shade. If a tree is shading part of your lawn, you could prune it to thin out branches and allow more sunlight and air circulation. Another option is to replace the lawn in the shade with shade-tolerant groundcovers or other plants.

How In Harmony Can Help

We are currently aerating and overseeding lawns for our clients. Call us if you would like us to do yours. We recommend aeration and overseeding once a year.

We can apply a moss control treatment to your lawn. Iron is used to burn the moss, turning it black. Iron will dehydrate moss but will not kill it. You will need to remove the moss with a thatching rake once it turns black. If it’s not raked out, it will come back more strongly. And if you don’t correct the conditions that favor moss, it will be a recurring problem.

We can renovate your lawn to correct drainage problems and improve fertility. In addition to removing moss, we would likely aerate, overseed and fertilize. If needed, we could alter the slope or fill in low spots and reseed.

We can prune your trees to allow more sunlight to reach shady spots and to improve air circulation. We can also work with you to create a shade garden to replace the lawn in areas where it is difficult to grow a healthy lawn.

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