Garden Myths - Learn the truth about gardening

Why does Moss Grow in Lawns?

The most common response to this question is that the lawn receives too much shade and that the soil is acidic. The common advice is that grass will grow better if you limb up the trees and add lime to the soil to make it less acidic. Or you can spread a moss killer for lawns.

What about moss that is growing in a sunny area? What about moss growing is soil that is alkaline? There is much more to the moss story.

How to get rid of moss in lawn

Mossy alkaline bolder at Aspen Grove Gardens

Moss in Lawn is Not a Sign of Acidic Soil.

Moss does prefer to grow in acidic soil, but it will grow just fine in alkaline soil. Part of my lawn is shady, wet and has a pH of 7.4. Moss grows much better than grass in that area. The picture above is a 4 foot high limestone  bolder that is covered in moss – it is certainly not acidic.

The common advice of liming the soil will make it less acidic is done properly, but it will not get rid of moss. Liming can actually make the situation worse. Unless you know for sure that your soil is too acidic for growing grass, do not add lime.

Moss is one of those plants that can grow in spots that are inhospitable to other plants, including:

  • Too much shade
  • Too wet
  • Compacted soil (ie lack of air in the soil)
  • Low fertility

When you have moss in your lawn, the moss is not the problem. The real problem is that you are trying to grow grass in a spot where it will not grow well. If the grass is not growing well, moss takes advantage of the situation and moves in. Moss will not invade a healthy growing lawn.

Moss Killer

You can spread lawn moss killer, which usually contains some form of iron sulphate (ferrous sulphate or ferrous ammonium sulphate). This will kill moss since moss does not grow well with high levels of iron in the soil. You can also rake out the moss and physically remove it from the lawn.

The problem with either if these options is that they do not work long term. Unless you fix the real problem ie grass not growing well, the moss will soon return to the lawn. There are really only two options. Leave things alone and embrace the moss as a natural ground cover, or fix the problem so that the grass grows better.

How to Get Rid of Moss in a Lawn?

In order to fix the problem, you need to first identify the problem, but any or all of the following will improve the growing conditions for the lawn.

–          Reseed with shade tolerant varieties of grass – if the area is shady

–          Aerate the soil – reduces compaction

–          Add organic matter to the soil

–          Fertilize more if there is a nitrogen deficiency

–          Reduce the amount of shade ie thin or limb up the trees

–          Water less if it is a wet area, water more if it is a dry area

–          Cut grass higher to encourage stronger grass roots

 Moss Grows in Full Sun

It is a myth that moss grows only in shady wet areas. There are many kinds of moss and some of them like to grow in dry sunny areas, even desserts. Sun loving moss will invade a sunny lawn.

Moss is Not Always Moss

There are some garden plants that look like moss and some that even have ‘moss’ in their name. The following are not true mosses

  1. Spanish Moss (is an epiphyte)
  2. Caribou Moss (is a lichen)
  3. Iris Moss (is a vascular plant)
  4. Scotch Moss (is a vascular plant)
Robert Pavlis
Editor of GardenMyths.com
I live in southern Ontario, Canada, zone 5 and have been gardening a long time. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

I hope you find Garden Myths an educational site that helps you understand your garden better.

7 Responses to 'Why does Moss Grow in Lawns?'

  1. Crystal Ezell says:

    I have moss going in one part of my yard it’s shaded by woods how can I kill it and what kind of grass could I plant there that would grow.

    • Don’t bother killing the moss. As my post described, you get rid of moss by growing better grass. Check with local horticulture societies, or Master Gardener groups to see which grass grows best in your area.

  2. John says:

    great info, thanks! a year ago we moved into this beautiful house and love that we are surrounded by trees, mostly hardwood. Our lawn is very small, and almost all of it has moss (or what we think to be moss), is typically shaded and wet. The previous owners did nothing, and that may be our ultimate decision as well. Is there a good way to identify those moss imposters?

  3. KL Eckhardt says:

    I think your comments were exactly “on point” for the information I was trying to find. I work for a sod company & have a customer whose yard is very shady and he has a great deal of moss. His land has not been taken care of for several decades (previous homeowners gave up on it). We have a good-for-shade fine fescue blend that we think will grow well for him. But while talking w/ him, he asked if we thought he needed lime to get rid of the moss. I’ve been taught a lot about the grasses we grow, but I wasn’t sure if moss indicated acidic or alkaline soil. I quickly typed in the question and your comments came up, among others. Your comment went immediately to the problem; I even read a sentence or two to our customer and gave him your URL. Now, I’m going to do more research to find out about “when moss isn’t moss” — thanks very much for your post.

    • Robert Pavlis says:

      I am glad you found this bog useful.

      • Warren says:

        This was very helpful! I built my home 8 years ago…I have a large yard which I’ve taken care of myself. 3 years ago I hired a local company to maintain my property and subsequently many issues became apparent, moss being one of them! I switched to a national service company and things got worse, so after a year I let them go! With your advice here I’m going to take on the task myself! Thanks again!

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