Moss is a familiar enemy to most turf care professionals in the UK, appearing on lawns, golf courses, bowling greens and other areas of sports and amenity turf.
The unfortunate truth is that our climate is perfect for it. Dark, wet winters allow moss to flourish; dominating any turfgrass species that are attempting to make it through the season.
What is moss?
Mosses are ancient plants that evolved 200 million years before the appearance of flowering plants such as grass. Mosses do not have roots; preferring to take all their water and nutrients directly through the leaf.
They also have the unusual ability that allows them to rehydrate after drying out, a useful trait to have if you want to survive the summer!
Why does moss grow so well in some turf?
Moss grows very well in damp, shady conditions which is why we often struggle to avoid moss growth in the winter months. Moss does not actually harm the grass plants but it will outcompete the grass if conditions are right.
It is often said that the presence of moss is an indicator of poor turf health, this is true because if the grass is not healthy then it will not be able to compete with the moss.
Typical factors encouraging moss over grass may be one or more of the following:
Waterlogged or very wet soil
Lack of adequate nutrients
Leaves not swept away
Increased stress levels (e.g. fertiliser scorch, herbicide applications, severe mowing)
What treatments are available for moss?
Iron sulphate has been used for many years as an economic and effective treatment against moss growth. It also has the added benefit of greening up the lawn making it highly popular as a winter treatment.
Iron sulphate can be applied in granular or liquid form, there are benefits to both methods but a liquid application will give the fastest results due to the direct action on the leaf. 6% Liquid Fairway Iron is based on iron sulphate and provides an economical and fast acting measure against moss. Black and Green is a granular fertiliser that allows high levels of iron to be applied and a longer lasting blackening/green-up effect to be seen.
Other granular moss-treatment products have recently become popular that do not contain iron sulphate. These products often have high potassium content and require application at rates of 1,000 kgs per hectare (100g per square metre) or more. Beneficial bacteria and fungi are also added to speed up the natural decomposition of dead moss, reducing the need for scarification. The success of these products is varied and trials carried out by our customers in the autumn were not conclusive. Further trials will be carried out in the spring.
Physical treatments for moss
Scarification is an excellent way to remove moss from lawns as well as removing thatch. It also plays an important role in maintaining lawn health year after year. The physical removal of moss will not prevent it from growing back but does allow the grass a chance to take hold.
Scarification must be done in the spring or early autumn to allow the lawn sufficient time to recover otherwise the moss will just grow back.
If an area of turf struggles with moss every winter then addressing the underlying cause is the only way to prevent further problems.
Improve turf health. Apply adequate fertiliser to the lawn throughout the year to enable strong, disease-resistant growth.
Scarify. Remove thatch buildup from the lawn to reduce the chance of fungal diseases and allow better access of air to the soil and roots. A high nitrogen fertiliser such as 14-3-6 will encourage the lawn to thicken rapidly after scarification.
Aerate. This has numerous other benefits for lawn health but it will also relieve soil compaction and facilitate better drainage, creating a dryer soil surface to suppress moss growth.
Mow correctly. Mowing at a very low height or cutting too much in one go will affect lawn health. It is also important to make sure mowing blades are sharpened regularly.
General maintenance. Fallen leaves, large trampolines and over-hanging trees all affect lawn health. Ensure leaves are swept regularly, move trampolines and other garden furniture once a week and cut back or prune any overhanging trees or shrubs.
Velvit is a wholesale fertiliser supplier to the professional turf care industry. Contact us to find out more about our products or how to find your local distributor.