There can be no mistaking Slime Mould on Lawns. Slime is exactly what it says! However, it does have some variants, and the term slime mould covers four or five different fungi that are sometimes found on lawns.
Fortunately slime is not a general problem on lawns. However, it will appear in damp places such as under the drip canopy of trees where the lawn is often permanently damp. You don't get dry slime! Slime can also appear on thinly populated grass areas which have been compacted.
It can either be green - as is most common - or even grey, pink or yellow in colour. Slime Mould itself does not do any harm to the soil since it is not a parasitic disease. It is the cause of slime which is the problem and should be dealt with.
Slime can be hosed off a lawn area. But the problem will still persist unless the underlying cause is dealt with..
It can also be brushed off in drier conditions.
The areas affected, should be aerated by spiking and also top-dressed in the autumn. Use a sandy mixture after spiking in order to improve drainage and ease compaction which is another cause of lawn slime.
Other than that, there is rarely any need for concerted action, and certainly no need to treat it with any chemical spray. Basically, it need the grass blades as a home to do its reproduction - without any parasitic action that affects the grass. As soon as it has done its business, it will disappear - normally after a couple of weeks..
Slime moulds are generally made up from a collection of single cell beings - half plant/half fungi! Singularly, the individual spores are invisible the the human eye, but tend to congregate in masses giving them the well deserved name of slime. The slime can either stay put for a few days, or can gradually spread across lawns - feeding on dead organic matter as it goes.
It can either be small patches, or larger patches that are sometimes mistakenly identified as something the cat or dog threw up!
The image shows a typical slime mould outburst.
They can sometimes be orange, yellow or brown in colour.. It can be found on any of the grasses or mixtures used in most lawns, and is not always seen a a gelatinous mass, but rather as thin strands - normally grey in colour.
As with so many other lawn problems, slime mould is happier in a slightly neglected lawn, and is not generally to be seen on a well cared for and nourished lawn. As stated above, it does not feed on grass, but relies an a supply of dead organic matter to feed. A well kept lawn will not have such matter in abundance!