Pro Lawn Help

Slime Mould

What is it?

Lawn mould is usually referred to as Slime Mould, a non-serious lawn condition that occurs more commonly within the summer/autumn months after periods of heavy rain.


How it develops

Slime Mould are primitive organisms called saprophytes. These organisms are responsible for breaking down dead or decaying matter.  The most common saprophyte disease is called Dollar Spot. The organisms obtain their nourishment from live grass blades.
In the case of Slime Mould, they only use the grass blade as a structure on which to grow spores.  The organisms produce small fruiting bodies on the outside of the leaf surface.  The fruiting bodies are about the size of a pin head but grow larger the more spores they produce.  The fruiting bodies range in colour from dark blue, to purple, to grey, and can grow from a few inches across, to several feet in diameter.
When seen on a lawn, many home-owners may try to just kick them off, in which a small puff of powdery substance will arise from the area as they release their spores from the Slime Mould. Finding a patch or two of Slime Mould should not be a cause for concern.  In a way, it’s actually a good thing as it may indicate that your lawn has plenty of microbial activity.


How to treat it

If you find a patch of Slime Mould you can either let nature take its course as the spores will fall away on their own, or you can use a broom to brush them off.  Alternatively, they can be hosed off with water.  Mowing will also dislodge the spores.  One thing to keep in mind - the spores that fall will remain in the soil or thatch and will re-grow again when the weather conditions are right.