Mosses are ancient plants and part of the division Bryophyta. Unlike flowering plants, Bryophytes do not have a vascular system to transport water and food. Mosses tend to favour conditions that are shaded, damp and compacted and can out-compete grass when these conditions present.
In lawns we tend to find a few different types of mosses due to varying conditions, which can be categorised as follows:
Cushion Forming: Can be seen as a result of repeated close mowing.
Trailing: This can be found in areas of shade with poor drainage and has a more feathered appearance.
Upright: Can be found in dry acidic soils.
How do you treat moss?
We routinely manage moss from autumn onwards and throughout the winter as part of our programme by way of a liquid treatment. This treatment draws the moisture out of the plant which can be seen by a blackening appearance. Afterwards, the dead moss can either be raked out or left in situ, soon to disappear as grass takes hold.
Heavier infestations may require scarification and over-seeding.
Can anything be done to prevent moss?
Whilst moss is an ongoing potential issue for any lawn, there are cultural treatments that can be carried out to improve the environment. The management of moss is a by-product of various activities to alter conditions including:
Compaction – Aeration performed annually will improve the compaction suited to moss, allowing water, air and nutrients into the grass root zone.
Moisture – Thatch is the organic layer that sits just below the surface and can hold the moisture levels so suited to moss. Scarification is the process by which this thatch layer is removed from the lawn. This also allows air and water to travel to where it is needed in the root zone, creating healthier, stronger grass.
Thicken Up Grass - Over-seeding a lawn in the autumn will provide an ideal time for early germination, and will thicken up a lawn heading into the winter months when moss is most prevalent.
Shade – If possible remove of reduce the causes of shade on the lawn.
Mowing - Raising the height of the cut to avoiding scalping the lawn.
Balanced Fertiliser Programme – providing the lawn with the correct balance of nutrients will lead to healthier grass, deeper roots and a density that can out-compete other species.