By first understanding why moss is growing, we can also understand the correlation of what is happening in the health of the lawn that it is allowing the moss to grow at all.
Moss thrives and grows in soil conditions that are usually moist and wet and heavily shaded. While in contrast, lawns will not tolerate growing under those same conditions of excessive moisture and combined shade. So with this in mind, if we have moss in our lawn, then we have optimal growing conditions for that moss to thrive, while also having the same conditions which causes lawns to deteriorate in health and to die off while living under those same environmental conditions.
So by removing the problematic conditions that cause moss to grow, we simultaneously improve the conditions in which lawns will grow and thrive. The purpose of this article then will be to improve environmental conditions to most greatly favor the lawn, while becoming the most hostile in which moss can grow, thereby removing the moss problem altogether and improving lawn health.
The number one environmental condition that favors moss and weakens lawns is when there is too much shade covering any lawn area. Therefore removing excessive shade is our highest priority to tackle the problem of moss in lawns.
Prune back all excessive growth from trees and shrubs to increase the amount of direct sunlight to the affected lawn area as much as possible. The more direct sunlight we can bring onto the lawn, the better. Moss will not grow in direct sun, and lawns love direct sunlight.
Continue to remove all other environmental conditions in the yard which may be causing excessive shade onto the lawn. This may be any type of shelter, fencing, shed, or other structure that can be moved to another place in the yard. Whatever object that can be moved away from the lawn, which is causing shade to the lawn, should be moved.
In areas where there is shade caused by objects which cannot be moved, like permanent fencing, a fixed shed or even the side of the house itself, then it may be a better option to remove the lawn altogether in that area and plant a shade tolerant garden bed, or to add paving, or outdoor storage or similar to that area, and to remove the lawn permanently.
The other major factor which encourages the growth of moss in lawns, as well as the deterioration of lawns, is the presence of large amounts of moisture that stay present in the soil for extended periods of time. So by removing this excessive moisture in these lawn areas that may be affected by moss, we then create a much more hostile growing environment for that moss to ever take hold.
This involves adjusting our lawn watering schedules if necessary, as well as making soil improvements if the soil itself is retaining too much water in its profile for too long.
We cannot cover all the factors involved in correct lawn watering in this article, as that is a long article in itself. Suffice to say that the homeowner should monitor the watering schedule at their property to determine if these can be reduced. This is an important factor, and any reduction to the water being applied to any lawn area affected by moss, is very important.
Next, we want to treat the soil itself in the affected area where moss is growing.
First dig out and dispose of the moss from the area.
Then we want to dig into the soil to determine its condition. Is the soil heavily compacted? Then we will need to heavily aerate and break up that soil. If the soil is very wet, then adjustments will need to be made to the soil so that water is more able to freely flow away. This is most often the case with clay or very silty soils, whereby we would then want to remove some of that soil and replace it with a coarse sand. The coarse sand is then mixed in with existing soil so that the area becomes more free draining of water.
If this type of soil improvement is undertaken, then we would want to treat the soil at a depth of up to a foot deep, turning over the soil and mixing in plenty of coarse sand, before finally levelling off and compacting the soil again.
For clay based soils, there are many different types of clay breaker products available to help treat clay soils, such as Gypsum type products. These should be strongly considered for use on clay soils where drainage is an issue for lawns.
After these soil repairs, we can then choose one of several options to repair the lawn itself, dependent on what type of lawn we have growing. Those choices will be to install new sod, or to re-seed the lawn area, or to allow the lawn to spread over the repaired soil area on its own – if the lawn is a runner type grass.