Moss is an increasing problem in many home lawns. Even lawns that have been under our care for years are being affected. We find that many of our properties that are surrounded by forest, or even just a section of taller trees, are being more affected by moss. The trees keep getting bigger and the shade slowly increases over the years. In many instances, a lawn that was mostly sunny a few years back has become shadier. Also, the increased use (and abuse!) of irrigation systems is a factor. These conditions are less favorable for grasses. Consequently, moss has an opportunity to become established.
What is Moss?
Mosses are non-vascular plants. All species of moss possess rhizoids instead of roots. This means moss is a rootless species, and doesn’t grow wood or flowers either. Instead of producing seeds for reproduction, which is common of many plant species, they produce spores. It’s part of a plant family that is millions of years old and therefore has proven to be adapatable to different climates.
Where is it commonly found?
Moss is a very opportunistic plant. It will grow where grass won’t. It doesn’t need to establish roots in the soil, but just germinates and becomes established at the surface. Moss will thrive in moist areas, such as:
shady areas
moist/poorly drained areas
poor soils
areas with excessive irrigation
low soil pH
How can we control it?
Since moss is usually a result of environmental conditions, we should concentrate on making those conditions less favorable for it and more favorable for grass. Grass needs more light and better drained soils than moss does. Grass roots need one amount of air to be successful. Soils that are constantly wet, or moist, will not contain enough air space for successful root development. Here’s what can be done:
Reduce the amount of shade by tree trimming and/or removal. This not only increases the amount of light, but also increases air flow, which will keep soils a little drier.
Avoid excessive irrigation in shadier areas. If you’re irrigating the shady areas as much as the sunny areas, you’re probably irrigating too much.
Monitor soil pH periodically. This doesn’t change rapidly, so checking every other year is appropriate.
Improve soil composition by adding quality topsoil.
Reduce compaction by periodic core aeration.
Commercially available moss killers may kill the existing moss, but it will return if the above conditions are not improved. That is why we don’t use them.